FIELD OF THE INVENTION
[0001] This invention relates to a method for making piles and to apparatus for practising
the method of the invention. A preferred embodiment of the invention provides a method
and apparatus for making piles to support the foundation of a structure, such as a
building.
BACKGROUND OF THE INVENTION
[0002] Piles are used to support structures, such as buildings, when the soil underlying
the structure is too weak to support the structure. There are many techniques that
may be used to place a pile. One technique is to cast the pile in place. In this technique,
a hole is excavated in the place where the pile is needed and the hole is filled with
cement. A problem with this technique is that in weak soils the hole tends to collapse.
Therefore, expensive shoring is required. If the hole is more than about 4 to 5 feet
deep then safety regulations typically require expensive shoring and other safety
precautions to prevent workers from being trapped in the hole.
[0003] Turzillo, United States Patent No. 3,962,879 is a modification of this technique.
In the Turzillo system a helical auger is used to drill a cylindrical cavity in the
earth. The upper end of the auger is held fixed while the auger is rotated about its
axis to remove all of the earth from the cylindrical cavity. After the earth has been
removed fluid cement water is pumped through the shaft of the auger until the hole
is filled with cement. The auger is left in place. Turzillo, United States Patent
No. 3,354,657 shows a similar system.
[0004] Langenbach Jr., United States Patent No. 4,678,373 discloses a method for supporting
a structure in which a piling bearing a footing structure is driven down into the
ground by pressing from above with a large hydraulic ram anchored to the structure.
The void cleared by the footing structure may optionally be filled by pumping concrete
into the void through a channel inside the pile. The ram used to insert the Langenbach
Jr. piling is large, heavy and expensive.
[0005] Another approach to placing piles is to insert a hollow form in the ground with the
piles desired and then to fill the hollow form with fluid cement. Hollow forms may
be driven into the ground by impact or screwed into the ground. This approach is cumbersome
because the hollow forms are unwieldy and expensive. Examples of this approach are
described in U.S. Patent Nos. 2,326,872 and 2,926,500.
[0006] Helical pier systems, such as the CHANCE™ helical pier system available from the
A.B. Chance Company of Centralia MO U.S.A., provide an attractive alternative to the
systems described above. As described in more detail below, the
CHANCE helical pier system includes one or more helical screws mounted at the end of a shaft.
The helical screw comprises a section of metal plate having its inner edge welded
to the shaft. The area around the inner edge is the root region of the screw. The
plate is bent so that its outer edge generally follows a helix. The shaft is turned
to draw the helical screw downwardly into a body of soil. The screw is screwed downwardly
until the screw is seated in a region of soil sufficiently strong to support the weight
which will be placed on the pier.
[0007] Brackets may be mounted on the upper end of the pier to support the foundation of
a building. Helical pier systems have the advantages that they are relatively inexpensive
to use and are relatively easy to install in tight quarters. Helical pier systems
have two primary disadvantages. Firstly, they rely upon the surrounding soil to support
the shaft and to prevent the shaft from bending. In situation where the surrounding
soil is very weak or the pier is required to support very large loads the surrounding
soil cannot provide the necessary support. Consequently, helical piers can bend in
such situations. A second disadvantage of helical piers is that the metal components
of the piers are in direct contact with the surrounding soil. Consequently, if the
shaft passes through regions in the soil which are highly chemically active then the
shaft may be eroded, thereby weakening the pier. A third disadvantage of helical piers
exists in piers which comprise large diameter helices which bear large loads. Such
helices can buckle and cause the pier to fail. Because their load bearing capacity
is limited, helical pier systems have not been able to replace more conventional piles
in many applications.
[0008] Raaf, United States Patent No. 5,575,593, discloses a method and apparatus for installing
an anchor used to improve the ability of soil to support structures and to provide
a tie-back anchoring force. The anchor includes a helical member which is hollow and
includes multiple perforated holes along its length. The helical member is rotated
into the ground and pressurized grout is injected through the hollow helical member
and out through the perforated holes. The grout fills any voids along the sides of
the anchor and stiffens the surrounding soil, such that it may be used to support
structures and to provide tie-back anchoring.
[0009] Vickars, United States Patent No. 5,707,180, provides a method for making piles and
an apparatus for practising the method. The method involves drawing a soil displacing
member on a shaft down through a body of soil by turning a screw at the lower end
of the shaft. The soil displacing member forces soil out of a cylindrical region surrounding
the shaft and then the cylindrical region is filled with grout to encapsulate and
strengthen the shaft. The grout may be fed by gravity into the cylindrical region
from a bath of grout surrounding the shaft. The soil displacing member may be a disk
extending in a plane perpendicular to the shaft.
[0010] There is a need for a relatively inexpensive method for forming piles without the
use of heavy expensive equipment which overcomes at least some of the above-noted
disadvantages of helical piers.
SUMMARY OF THE INVENTION
[0011] This invention provides methods for forming piles which use a screw to pull a soil
displacing member through soil. One aspect of the invention provides methods to protect
the screw with a hardenable substance after the screw has been inserted into the ground.
A preferred embodiment comprises encasing at least a root portion of the screw in
solidified grout. This protects the root portion of the screw from corrosive soils
and reinforces the screw. In the preferred embodiment the method includes the steps
of removing soil from a volume surrounding at least a root portion of the screw by
holding the shaft against longitudinal motion, turning the screw in a first sense
and forcing a fluid grout under pressure into the volume; and, allowing the grout
in the volume to harden, thereby encasing surfaces of the screw in a protective layer
of solidified grout. Preferably the fluid grout is forced under pressure into the
volume while the screw is rotating. Most preferably the fluid grout is forced under
pressure into the volume by forcing the fluid grout under pressure through a longitudinal
channel within the shaft and directing the grout into the volume through apertures
in a wall of the shaft.
[0012] Another preferred embodiment of the invention provides a method adapted to create
a stepped pile. In this method, the screw pier comprises a plurality of additional
soil displacing members having diameters larger than a diameter of the first soil
displacing member, the additional soil displacing members at spaced apart locations
on the portion of the shaft between the second end and the first soil displacing member.
The additional soil displacing members toward the second end have diameters larger
than diameters of the additional soil displacing members toward the first soil displacing
member. The method includes drawing the additional soil displacing members through
the soil to stepwise increase a diameter of the cylindrical region.
[0013] A further aspect of the invention provides a screw pier for making a grout encased
pile. The screw pier comprises: a lead section comprising a screw, a head and a soil
displacement member between the screw and the head; an elongated shaft having a first
end coupled to the lead section head; an elongated drive tool having a socket in driving
engagement with the lead section head, the elongated shaft extending through a central
bore in the drive tool; and a fastener at a second end of the elongated shaft, the
fastener holding the drive tool socket engaged with the lead section head. After placement
of the screw pier the drive tool may be removed and re-used. In a preferred embodiment,
the drive tool comprises two or more sections connected by one or more joints and
each joint comprises a head end of one drive tool section received in a socket on
one end of another drive tool section. the socket is movable longitudinally relative
to the head end between first and second positions. When the socket is in its first
position, an edge of the socket projects past an abutment on the head end to provide
a recess facing the screw. The recess is capable of receiving tab portions of sectors
of a soil displacing member. When the socket is in its second position, the edge of
the socket is retracted, thereby releasing the tab portions of the sectors.
[0014] The invention also provides a drive tool for installing a grout encased screw pier.
The drive tool comprises an elongated shaft penetrated by a central bore. The shaft
comprises two or more sections connected by one or more joints. The drive tool has
a socket for drivingly coupling to a screw pier lead section at one end of the shaft.
Each of the joints comprises a head end of one shaft section slidably received in
a socket on one end of another shaft section. The socket is movable longitudinally
relative to the head end between first and second positions. When the socket is in
its first position, an edge of the socket projects past an abutment on the head end
to define a recess facing toward the first end of the shaft. When the socket is in
its second position, the edge of the socket does not project past the abutment.
[0015] Other embodiments and aspects of the invention are set out in the following drawings
description and claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] In drawings which illustrate preferred embodiments of the invention, but which should
not be construed as restricting the spirit or scope of the invention in any way:
Figure 1 is an elevational view a prior art helical pier installed in a body of soil
and supporting a building foundation;
Figure 2 is a side elevational view of apparatus for practising this invention;
Figure 3 is a top plan view of a plate for use with the invention;
Figures 4A, 4B, 4C and 4D are schematic views of steps in practising the method of
the invention;
Figure 5 is a top plan view of an alternative disk for practising the invention;
Figure 6 is a perspective view of a pile made according to the invention reinforced
with additional length of reinforcing material;
Figure 7 illustrates the method of the invention being used to manufacture a cased
pile;
Figures 8A and 8B are respectively a top plan view and a side elevational view of
a plate for use with the method of the invention for making a cased pile;
Figure 9 is a section through an alternative embodiment of the apparatus for practising
the invention wherein grout may be introduced through a channel in a central shaft;
Figure 10 is a top plan view of a fenestrated disk for use with the invention;
Figure 11 illustrates the method of the invention being used to make a stepped pile;
Figure 12 is an elevational view of apparatus according to an embodiment of the invention
which permits a screw to be encased in a layer of grout;
Figure 13 shows a soil displacement member equipped with paddles;
Figure 14 is a flow chart illustrating steps in a method according to one embodiment
of the invention;
Figure 15 is a schematic elevational view of apparatus according to an alternative
embodiment of the invention;
Figure 16 is a partial elevational section through a joint thereof in a first position;
Figure 17 is a partial elevational section through a joint thereof in a second position;
Figure 18 is a transverse section on the line 18-18 of Figure 16; and,
Figure 19 is a transverse section along the line 19-19 of Figure 16.
DETAILED DESCRIPTION
Prior Art
[0017] Figure 1 shows a prior art helical pier
20 supporting the foundation
22 of a building
24. Helical pier
20 has a lead section
30 which comprises a shaft
32 and a screw
34 mounted to shaft
32. Usually shaft
32 comprises a number of extension sections
36 which are coupled together at joints
37. Each extension section
36 comprises a shaft section
39 and a socket
38. Shaft sections
39 are typically square in section but may, of course, have other shapes. Sockets 38
comprise a square recess which fits over the top end of lead section
30 or the top end of the shaft section
39 of a previous one of extension sections
36. Bolts
40 are then used to secure extension sections
36 together. Lead sections are typically available in lengths in the range of 3 feet
to 10 feet. Lead section
30 shown in Figure 1 has a helical screw
34 comprising two helical segments attached to it. Screw
34 may comprise one or more helical segments. Additionally, some of extension sections
36 may also be equipped with screws
34.
[0018] Helical pier
20 is installed in the body of soil underlying foundation
22 by screwing lead section
30 into the earth adjacent foundation
22 and continuing to turn lead section
30 so that helical screw
34 draws lead section
30 downwardly. As lead section
30 is drawn downwardly extension sections
36 are added as needed. The installation is complete when helical screw
34 has been screwed down into a layer of soil capable of supporting the weight which
will be placed on pier
20. In the example of Figure 1, helical screw
34 has been screwed down through two weaker layers of soil
46 and
48 and into a layer
50.
[0019] A bracket
54 at the top of helical pier
20 supports foundation
22. Bracket 54 may be equipped with lifting means, as described, for example, in U.S.
patent Nos. 5,120,163; 5,011,336; 5, 139,368; 5,171,107 or 5,213,448 for adjusting
the force on the underside of foundation
22.
[0020] A problem with the pier shown in Figure 1 is that the pier can bend, and may even
buckle, if the soil in regions
46 and/or
48 is not sufficiently strong to support shaft
32 against lateral motion. This tendency is exacerbated because sockets
38 are somewhat larger in diameter than shaft sections
39. Consequently, as sockets
38 are pulled down through the soil they disturb and further weaken a small cylindrical
volume
52 of soil immediately surrounding shaft
32. Furthermore, there is generally some clearance between the side faces of shaft sections
39 and the walls of the indentations in sockets
38. Shaft
32 is therefore freely able to bend slightly at each of joints
37. It can be readily appreciated that when shaft
32 is in compression, the forces tending to push shaft
32 laterally are increased as shaft
32 becomes bent.
[0021] A second problem with the pier shown in Figure 1 is that it is prone to corrosion.
Generally pier
20 will be installed so that screw
34 is in a layer of soil
50 which will not corrode screw
34. In many cases, however, shaft
32 passes through other layers of soil which are more chemically active. In the example
shown in Figure 1, shaft
32 is in direct contact with the soil of layer
48 which may be highly corrosive. In the example shown in Figure 1, even if screw
34 is imbedded in the layer of soil
50 which is chemically inert, the integrity of the entire pier
20 may be reduced if layer of soil
48 is highly chemically active and erodes those portions of shaft
32 which pass through layer of soil
48.
[0022] As an example of the problems which can occur in the use of prior art helical piers,
several
CHANCE™ SS150-1½" square shaft compression anchor were placed in alluvial soils in Delta,
British Columbia, Canada. The shafts were then loaded. It was found that the shafts
of the piers failed by buckling when the applied loads were in the range of about
11,000 kg (25,000 lbs.) to about 16,000 kg (35,000 lbs.). To provide a desired 2 to
1 safety factor it was necessary to limit the loading on each such pier to no more
than approximately 7,000 kg (15,000 Ibs.) per pier. This increased the number of piers
needed to support the structure in question.
This Invention
[0023] Figure 2 shows apparatus
51 for practising the method of the invention to make a pile
65 (see Figures 4C and 4D). Pile
65 may be used to support a structure, which, for clarity, is not shown. Apparatus
51 comprises a helical pier
20, which is preferably a helical pier of the general type described above as shown
in Figure 1 and available from the A.B. Chance Company of Centralia MO. Other types
of helical pier could also be used, as will be readily apparent to those skilled in
the art, after reading this specification. Helical pier
20 is modified for practising the invention by the addition of a soil displacing member
which preferably comprises a disk
60 on shaft
32, spaced above screw
34. Disk
60 projects in flange like fashion in a plane generally perpendicular to shaft
32. One or more additional soil displacing members which are preferably additional disks
62 are spaced apart along shaft
32 above disk
60.
[0024] Soil displacing members for use with the invention may have various forms without
departing from the invention. For example, instead of a disk
60 the soil displacing member may comprise a section of shaft
32 having an enlarged diameter. For example, as sockets
38 are manufactured, a portion of the material being used to form the socket may be
flared outwardly in a flange-like fashion. The outwardly flared material can function
as a soil displacement member without the necessity of separate parts. In some denser
soils, the sockets
38 on prior art helical piers, as described above, might be large enough for use in
practising the methods of the invention on a limited scale, although a larger diameter
soil displacing member is generally preferred. Generally the diameter of the soil
displacing member should be at least about twice the diameter of shaft
32. Soil displacing members should be sufficiently rigid that they will not be unduly
deformed by the forces acting on them during installation of a pile, as described
below.
[0025] Disk
60 may be rigidly held in place on shaft
32 but may also be slidably mounted on shaft
32. Where disk
60 is slidably mounted on shaft
32 it is blocked from moving very far upwardly along shaft
32 by a projection formed by, for example, the lowermost one of sockets
38. Preferably the apparatus includes one or more additional disks
62. Disks
62 are not necessarily all the same size and may be larger or smaller than disk
60 as is discussed in more detail below.
[0026] The preferred dimensions of disks
60,
62 and screw
34 depend upon the weight to be borne by pile, the properties of the soil in which pile
65 will be placed and the engineering requirements for pile
65. For example, in general: if the soil is very soft then larger disks may be used;
if the soil is highly chemically active then larger disks may also be used (to provide
a thicker layer of grout to protect the metal portions of the apparatus as described
below); and if the soil is harder then smaller disks may be used. Disks
62 are spaced apart from disk
60 along shaft
32.
[0027] All of disks
60 and
62 are typically smaller than screw
34. For example, screw
34 is typically in the range of 15 cm (6 inches) to 36 cm (14 inches) in diameter. Shaft
sections
39 are typically on the order of 3.8 cm (1.5 inches) to 5.1 cm (2 inches) in thickness
and disks
60, 62 are typically in the range of 10 cm (4 inches) to 41 cm (16 inches) in diameter.
The preferred size for disks
60 depends upon the weight that will be borne by the pile, the relative softness or
hardness of the soil where pile
65 will be placed and on the diameter of screw
34.
[0028] A disk suitable for use as disk
60,
62 is shown in Figure 3. Disk
60 may, for example, comprise a circular piece of steel plate thick enough to withstand
significant bending forces as it is used and most typically approximately 6.35 mm
(.25 inches) to 9.5 mm (3/8 inches) in thickness with a hole
64 at its centre. Preferably disks
60,
62 are galvanized although this is not necessary. Hole
64 is preferably shaped to conform with the cross sectional shape of shaft
32 so that disk
60 can be slid onto shaft sections
39. Hole
64 is smaller than joints
37. As will be readily appreciated from a full reading of this disclosure, disks
60 and
62 do not necessarily need to be flat but may be curved and/or dished. Flat disks
60,
62 are generally preferred because they can work well and are less expensive to make
than curved or dished disks.
[0029] Disk
60 displaces soil from a cylindrical region
74 around shaft
32 as it is pulled downwardly through the soil by screw
34. As described above, disk
60 may be replaced with an alternative soil displacing member which will clear cylindrical
region
74 of soil as it is pulled through the soil by screw
34. It will readily be apparent to those skilled in the art that various members of
different shapes or configurations may be attached to shaft
32 in place of disk
60 to displace soil from a generally cylindrical volume surrounding shaft
32 and that such members can therefore function as soil displacing members within the
broad scope of this invention.
[0030] The method provided by the invention for making and placing a pile
65 is illustrated in Figures 4A through 4D. First, shown in Figure 4A the lead section
30 of a helical pier is turned with a suitable tool
72 so that screw
34 is screwed into the soil at the point where a pile is desired. After screw
34 has screwed into the soil, disk
60 is slipped onto the shaft portion of lead section
30 and a tubular casing
66 is placed around the projecting shaft of lead section
30. The lower edge of tubular casing
66 is embedded in the surface of soil
46. Tubular casing
66 is then partially filled with fluid grout
70 and the level of grout
70 is marked.
[0031] Optionally, casing
66 may be placed first at the location where it is desired to place pile
65 and lead section
30 may be introduced downwardly through casing
66 and screwed into the soil inside casing
66 either before or after grout
70 has been introduced into casing
66. Where lead section
30 is started after grout
70 has been placed in casing
66 then grout
70 may lubricate screw
34 and thereby reduce the torque needed to start screw
34 into the soil beneath casing
66.
[0032] Tubular casing
66 typically and conveniently comprises a round cardboard form approximately 61 cm (24
inches) high and approximately 46 cm (18 inches) in diameter. However, casing
66 may be any form capable of holding a bath of fluid grout
70 and large enough to pass disks
62. It is not necessary that casing
66 be round although it is convenient and attractive to make casing
66 round.
[0033] In some cases, for example where a pile is being installed through a hole in a cement
foundation, it may be unnecessary to provide a separate casing
66 because a suitable bath of fluid grout
70 may be formed and kept in place by pouring fluid grout
70 directly into the hole or an excavation in the soil immediately under the hole.
[0034] Next, as shown in Figure 4B, an extension section
36 is attached to lead section
30 and a driving tool is attached to the top of extension section
36 to continue turning shaft
32 and screw
34. Shaft
32 slips through then centre of disk
60 until first joint
37 hits disk
60. Subsequently, screw
34 pulls disk
60 down through soil
46. Disk
60 compresses and displaces the soil below its lower surface as disk
60 is pulled downwardly. As this happens, grout flows downwardly under the action of
gravity from tubular casing
66 into a cylindrical region
74 which disk
60 has cleared of soil.
[0035] As disk
60 is pulled downwardly, grout
70 flows into cylindrical region
74 and the level of grout
70 in tubular casing
66 goes down. Tubular casing
66 is periodically refilled with grout. Preferably the amount of grout introduced into
tubular casing
66 is measured so that the total amount of grout which flows into cylindrical region
74 may be readily calculated. This information may be needed obtain an engineer's approval
of pile
65.
[0036] As shown in Figure 4C, additional disks
62 on additional extension sections
36 are added as screw
34 pulls disks
60 and
62 downwardly through soil
46 until, ultimately, screw
34 is embedded in a stable layer
50 of soil. Disks
62 maintain shaft
32 centered in cylindrical region
74 and may also help to keep soil from collapsing inwardly into cylindrical region
74. In some applications only one or two disks
60, 62 may be necessary. Tubular casing
66 is then removed and grout
70 is allowed to harden. Tubular casing
66 may also be left in place.
[0037] The end result, as shown in Figure 4D, is that extension sections
36 are encased in a hardened cylindrical column of grout
70. Hardened grout
70 prevents extension section
36 from moving relative to one another and reinforces the portions of shaft
32 above disk
60. Grout
70 also protects shaft
32 from corrosion. The diameter of the column of grout
70 surrounding shaft
32 depends upon the diameter of the soil displacement means (i.e. disk
60 in the embodiment shown in Figure 4) being used.
[0038] As disk
60 is drawn down through soil
46 disk
60 forces soil
46 outwardly and downwardly so that the soil surrounding cylindrical region
74 is somewhat compressed. This helps to retain grout
70 in cylindrical region
74 and also helps to make pile
65 resistant to lateral motion in soil
46 after grout
70 has solidified. The hydrostatic pressure of grout
70 in cylindrical region
74 also helps to keep soil from collapsing inwardly into cylindrical region
74 before grout
70 hardens.
[0039] Where disks
62 are solid, disks
62 may, in some soils, seal against the walls of cylindrical region
74 and isolate portions of cylindrical region
74 between disks
62. If this happened then the hydrostatic pressure of grout
70 in one or more of the isolated portions could be reduced if grout
70 leaked out of that portion into the surrounding soil. This could tend to allow the
surrounding soil to collapse into cylindrical region
74. As shown in Figure 10, disks
62 may be of a type
62B provided with fenestrations
73 so that the column of grout
70 in cylindrical region
74 is not interrupted by disks
62. This allows the full hydrostatic head of fluid grout
70 in cylindrical region
74 to press outwardly against the soil adjacent cylindrical region
74.
[0040] After grout
70 hardens, the hardened cylindrical column of grout
70 has a diameter similar to the diameter of disk
60, which is significantly larger than the diameter of shaft
32. It therefore takes a larger lateral force to displace pile
65 in soil of a given consistency than would be needed to displace the prior art helical
pier
20 shown in Figure 1. Therefore, pile
65 should have a significantly increased capacity for bearing compressive loads than
a prior art helical pier
20 with a similarly sized shaft
32 and screw
34.
[0041] Grout
70 is preferably an expandable grout such as the
MICROSIL™ anchor grout, available from Ocean Construction Supplies Ltd. of Vancouver British
Columbia Canada. This grout has the advantages that it tends to plug small holes and
rapidly acquires a high compressive strength during hardening. Another property of
this grout is that it resists mixing with water. Preferably grout
70 is fiber reinforced. For example, it has been found that the
MICROSIL grout referred to above can usefully be reinforced by mixing it with fibrillated
polypropylene fiber, such as the
PROMESH™ fibers available from Canada Concrete Inc. of Kitchener, Ontario, Canada according
to the fiber manufacturer's instructions. Typically approximately 0.7 kg (1.5 pounds)
of fibers are introduced per 0.76 cubic meters (cubic yard) of grout
70 although this amount may vary. Other soil specific additives may be mixed with the
grout as is known to those skilled in this art.
[0042] This invention could be practised in its broadest sense by using for grout
70 any suitable flowable material, such as, for example, cement or concrete, which will
firmly set around shaft
32 after it is introduced into cylindrical region
74. Preferably, after it sets, grout
70 seals materials which are embedded in it from contact with any corrosive fluids which
may be present in the surrounding soil.
[0043] Because shaft
32 is placed in tension as screw
34 pulls disks
60, 62 downwardly through soil
46, it is desirable to compress shaft
32 before grout
70 hardens. After each pile
65 has been placed, and before grout
70 hardens, the projecting end of shaft
32 atop pile
65 is hammered with a heavy hammer, for example, a 7-11 kg (16-25 pound) sledge. The
amount that pile 65 will collapse depends upon the amount of play in joints
37. Usually there is approximately 3.2 mm (1/8 inch) of play per joint
37 so that for a pile
65 which comprises 5 or 6 extension sections
36 one would expect shaft
32 to collapse by approximately 16-19 mm (5/8 to 3/4 inch) when it is compressed after
placement. The amount of collapse of shaft
32 is preferably measured to verify proper placement of pile
65.
[0044] After pile
65 has been placed then it may be attached to a foundation or other structure in a manner
similar to the way that prior art helical piers
20 are attached to foundations, as discussed above.
[0045] Stepped piles generally have greater load bearing capacities than piles having a
constant outer diameter. This invention provides a convenient and relatively inexpensive
way to create a stepped pile. As shown in Figure 11, a series of additional soil displacing
members, such as disks
62, may increase in diameter in steps along the length of shaft
32. Each larger diameter disk
62 increases the diameter of the portion of cylindrical region
74 that it is pulled through. After the pile has been formed, the largest diameter disks
62A are nearest the surface of the ground, the smallest diameter disks
62C are deepest in the ground and intermediate diameter discs
62B lie along shaft
32 between large discs
62A and smaller discs
62C. As shown in Figure 11, the result is a pile
130 having a stepped diameter. The largest diameter sections of pile
130 are in the softer layers of soil
46 and
48 nearest the surface. For example, disk
60 and those of disks
62 in the lowermost 3-6 m (10 to 20 feet) of a 12-15 m (40 to 50 foot) pile
130 could be in the range of about 15 cm (6 inches) to 20 cm (8 inches) in diameter,
the disks
62 in the next 3 m (10 feet) or so could be about 25 cm (10 inches) in diameter, the
disks
62 in the next 3 m (10 feet) or so could be about 36 cm (14 inches) in diameter and
the terminal 3 m (10 feet) or so of the pile could have disks
62 of about 46 cm (18 inches) in diameter.
[0046] In some cases a stepped pile
130 will be installed in a place where the topmost layers
46 of soil are very soft. In such cases, additional support may be provided for the
uppermost portions of pile
130 by making the uppermost disk or disks
62 significantly larger than disk
60. When screw
34 is in a deeper denser layer
50 of harder soil then it can pull a relatively large disk
62 downwardly through an overlying layer
46 of much softer soil. If surface layers
46 and/or
46 and
48 are extremely soft then one or more of disks
62 closest the surface may be even larger in diameter than screw
34. This is possible when screw
34 has enough purchase in denser layer
50 to pull a larger diameter disk
62 (or other soil displacing member) down through softer layer
46. In cases where the upper layers of soil are extremely soft it is often desirable
to have the uppermost sections of the pile encased in a sleeve made, for example,
from a section of steel pipe. This can be accomplished as described below with reference
to Figure 7.
[0047] In prior art driven piles can be difficult to predict where the pile will "bottom
out" and it is therefore complicated to design a pile so that the portion of the pile
in the topmost layers of soil is, for example, thicker than other portions of the
pile. With a pile
65 made according to this invention it is possible to reverse the direction of rotation
of screw
34 after screw
34 "bottoms out" to bring one or more of the topmost disks
62 to the surface. The removed disks can then be replaced with larger disks
62 and screw
34 can be screwed back into the ground to produce a pile
65 in which the surface portions of the pile have a large diameter. By contrast it is
very difficult to pull up a standard driven pile after the pile has been hammered
into the ground.
[0048] Many variations to the invention are possible without departing from the scope thereof.
For example, as described above, soil displacement means for use with the invention
may have many shapes, sizes and thicknesses. Screw
34 need not be a helical screw exactly as shown in the prior art but may have other
forms. What is particularly important is that screw
34 is capable of drawing a soil displacement member, for example a disk or flange on
shaft
32, through the soil as screw
34 is turned.
[0049] As shown in Figure 6, it is possible to reinforce a pile
65 created according to the invention with lengths of reinforcing material
75, such as steel reinforcing bar, which extend through cylindrical region
74. In many applications, reinforcing material
75 may conveniently be 10 to 15 millimeters in diameter although, for some jobs, it
may be larger or smaller. For use with lengths of reinforcing material
75 it is preferable that disks
60,
62 have apertures in them through which lengths of reinforcing material
75 can be passed.
[0050] Figure 5 shows an alternative disk
60A which has in it a number of apertures
77 for receiving the ends of length of reinforcing material
75. Lengths of reinforcing material
75 are inserted into apertures
77 as disks
60A are drawn down into cylindrical region
74. Each length of reinforcing material
75 extends through an aperture
77 in a disk
60A. Lengths of reinforcing material are made to overlap to meet applicable engineering
standards. Apertures
77 hold reinforcing material
75 in place. Lengths of reinforcing material
75 may optionally be welded to disks
60A or
60,
62. Lengths of wire and/or stirrup reinforcements may be used to tie reinforcing material
75 in place during placement and until grout
70 sets.
[0051] As shown in Figure 6, pile
65 may be further reinforced by wrapping one or more additional lengths of reinforcing
material
75 around shaft
32 in a spiral inside cylindrical region
74. This is conveniently be done while pile
65 is being installed. A length of reinforcing material
75 can simply be attached to the pile and allowed to wind around the pile as the pile
is turned and pulled down into the ground.
[0052] As shown in Figures 7 and 8, the method of the invention may also be used for making
a cased pile
79 which extends inside a tubular casing
78. Where it is desired to make a cased pile
79 it is preferable that disks
60B as shown in Figures 8A and 8B are used. Disks
60B have a flange
80 projecting around their perimeter. Flange
80 is slightly larger in diameter than the exterior diameter of casing
78. The other portions of disks
60B are slightly smaller in diameter than the inner diameter of casing
78. The end of a length of casing
78 is held in contact with flange
80 on disk
60B as disk
60B is pulled into the ground. Casing
78 is dropped into the ground behind disk
60B. Disk
60B keeps casing
78 centered around shaft
32. A separate length of casing
78 is preferably used for each extension section
36 of shaft
32. Casing
78 may comprise, for example, a section of pipe, such as PVC pipe. Casing
78 may be used, for example, where the soil has voids in it into which fluid grout
70 would otherwise escape.
[0053] While the methods described above have introduced fluid grout
70 into cylindrical region
74 by feeding grout
70 from a grout bath under the action of gravity, grout
70 may also be introduced into cylindrical region
74 in other ways. For example, as shown in Figure 9, shaft
32 may have a central tubular passage
90 and at least one, and preferably a number of, apertures
92 extending from tubular passage
90 into cylindrical region
74. Fluid grout
70 may then be pumped downwardly through tubular passage
90 and into cylindrical region
74 through apertures
92 either after screw
34 has been screwed to the desired depth or at a point during the installation of screw
34. In the further alternative, a pipe for pumping fluid grout into cylindrical region
74 may run alongside shaft
32 through suitable apertures in plates
62.
[0054] The methods described above can produce a pile which is encased in grout above the
level of disk
60. However, screw
34 may remain vulnerable to attack by corrosive agents in the soil in which it is embedded.
Over time such corrosion could reduce the capacity of the pile. The methods of this
invention may be extended to encase screw
34 a suitable grout or another suitable protective medium. The objective is to form
a protective ball of solidified grout around at least the root portion
104 of screw
34. The solidified grout both protects screw
34 from attack by corrosive soils and reinforces screw
34 against buckling under load.
[0055] As shown in Figure 12, shaft
132 has a central conduit
100 extending longitudinally through to one or more apertures
106 in the vicinity of root
104 of screw
34. Shaft
132 may be inserted into the ground as described above (Fig 14, step
206). After screw
34 has been screwed to its desired depth, as described above, grout or another suitable
medium may be forced through conduit
100 under high pressure (step
210B). The grout is delivered into a region
102 surrounding screw
34 through apertures
106 until it coats screw
34. It is generally not sufficient to simply pump pressurized grout into region
102 because it will generally not be possible to introduce grout into region
102 in a way such that the flowing grout will reliably displace corrosive soils from
contact with screw
34.
[0056] Screw
34 is operated to remove soil surrounding screw
34 from area
102 (step
210A) either during or just before the introduction of grout into region
102. This may be done, for example, by preventing shaft
132 from moving vertically while turning screw
34. Screw
34 then acts like an auger and displaces soil from region
102 either upwardly or downwardly depending upon the direction in which screw
34 is turned. Most preferably, screw
34 is turned in a sense which would move screw
34 deeper into the soil while shaft
132 is prevented from moving deeper. The soil in region
102 is thus displaced toward the lowermost soil displacing member (e.g. disk
60).
[0057] Shaft
132 may be prevented from moving deeper by coupling its upper end with a thrust bearing
to a large plate or the like lying on the surface of the ground. The plate is too
large to be pulled downwardly by screw
34. The thrust bearing allows shaft
32 to turn relative to the large plate.
[0058] Preferably, the soil in region
102 is loosened (step
208) before step
210 by repeatedly turning screw
34 through several turns in alternating directions of rotation.
[0059] As shown in Figure 12, during step
210 grout flows upwardly from apertures
106, as indicated by arrows
107 and helps to carry soil out of region
102. The flowing grout is deflected outwardly at disk
60. Preferably disk
60 is not more than about 20 cm (8 inches) above screw
34. Most preferably disk
60 is not more than about 10-15 cm (4-6 inches) above screw
34. Preferably disk
60 has paddles
110 oriented as shown in Figure 13 to drive soil and grout outwardly when disk
60 turns in the direction indicated by arrow
109. The result is that the root portion
104 of screw
34 and the lower portions of shaft
32 become encased in a ball of grout.
[0060] If screw
34 is embedded in a layer of non-cohesive soil, such as sand, then it may be possible
to perform step
210 in two separate steps, first turning screw
34 to remove soil from region
102 (step
210A) and subsequently pumping grout into region
102 (step
210B). Most preferably, however, grout is introduced through apertures
106 at the same time as screw
34 is turned. The turning screw
34 both removes soil from region
102 and distributes grout through region
102.
[0061] While it is not preferred, step
210 may be performed by turning screw
34 in a sense that would tend to cause screw
34 to move upwardly. Shaft
132 may be prevented from moving upwardly by bearing down on its upper end with a heavy
machine, such as a backhoe. Screw
34 then tends to push soil downwardly out of region
102. In this case, apertures
106 would be on shaft
132 near the upper end of screw
34.
[0062] Especially where screw
34 is a helix, screw
34 is preferably modified so that soil is cleared from a volume that is slightly larger
in diameter than the bearing surfaces of screw
34 during the steps described above. For example, short radially outwardly projecting
tabs
111 may be provided on the leading edge and/or leading and trailing edges of screw
34. During step
210 when screw
34 is operated to remove soil from region
102, tabs
111 loosen the soil in a cylindrical shell area around screw
34. When grout is pumped into region
102 the grout can flow into the cylindrical shell area and around the outside edges of
screw
34 through the cylindrical shell area. The grout can thereby form a protective ball
around the edge surfaces of screw
34. The outer edge of screw
34 may be serrated to achieve a similar effect.
[0063] Finally, (step
212) the grout is allowed to harden around screw
34 and shaft
32. The hardened grout around screw
34 both protects screw
34 from corrosion and reinforces screw
34 against buckling.
[0064] The torque which shaft
32 must transmit to screw
34 is increased if the soil through which screw
34 is being screwed is very hard or if a soil displacement member is being drawn through
a hard layer of soil. In some cases shaft
32 must be made significantly stronger than would be otherwise necessary to transmit
the necessary torque to screw
34. This could make inserting a pile according to the invention more expensive. Figures
15 through 19 illustrate an alternative system
300 according to the invention in which torque is transmitted to screw
34 through a removable driving tool
332. After screw
34 has been screwed to the desired depth then driving tool
332 may be removed and re-used.
[0065] System
300 has a screw
34 and a soil displacing member
60 mounted on a lead section
330. A shaft
333 extends upwardly from a head end
320 of lead section
330. Shaft
333 does not need to be strong enough to transmit the torque necessary to screw screw
34 to its desired location.
[0066] Driving tool
332 has a central bore
328. Driving tool
332 is placed over shaft
333 with shaft
333 passing through bore
328. A socket
340 on the lower end of driving tool
332 engages a head
341 on head end
320 of lead section
330. Head
341 and socket
340 may, for example, be square in section. A fastener
343 at the upper end of shaft
333 holds driving tool
332 in engagement with lead section
330. Rotating driving tool
332 about its axis turns lead section
330. The torque for turning screw
34 is delivered primarily through driving tool
332 and not through shaft
333. Shaft
333 could have a central bore connecting to a bore in lead section
330 to allow the methods described above with reference to Figure 12 to be used to encase
screw
34 in grout.
[0067] Driving tool
332 preferably comprises a lower section
331 having a socket
340 adapted to engage lead section
330 and a number of intermediate sections
336 that may be added to increase the overall length of driving tool
332 as screw
34 enters the ground. Each section
336 has a socket
340A at one end and a head
342 at its other end. The head
342 of the uppermost section may be engaged by a rotary tool to turn driving tool
332 about its axis and to thereby turn screw
34. Shaft
333 may conveniently comprise a series of screw-together sections
324 each a few feet long. Fastener
343 may be removed to permit the addition of more sections
324 and
336 and then replaced to continue the installation. Sockets
340A and heads
342 may be the same as or different from socket
340 and head
341 respectively.
[0068] After screw
34 has been installed at the correct depth then fastener
343 may be released and driving tool
332 may be removed from around shaft
333 while leaving shaft
333 in place. Driving tool
332 may then be rinsed to remove any fluid grout adhering to it and re-used.
[0069] Additional soil displacement members
362 may optionally be mounted to driving tool
332. Additional soil displacement members
362 should be attached to driving tool
332 in such a manner that they do not remain attached to driving tool
332 but fall away as driving tool
332 is withdrawn from around shaft
333. Figures 16 through 19 show one possible way to mount additional soil displacement
members
362 on driving tool
332.
[0070] As shown in Figure 16, each section
336 of driving tool
332 has a socket
370 which slidably receives the head end
372 of the next section of driving tool
332. Head end
372 comprises abutments
374 which project outwardly from an adjoining portion
373 of head end
372. The outer faces of abutments
374 engage with the inner faces of socket
370 so that head end
372 is prevented from turning in socket
370. Sockets
370 are coupled to head portions
372 by fastening members which, in the drawings, are illustrated as pins or bolts
380. Fastening members
380 permit socket
370 to slide relative to head portion
372 between a first position (as shown in Figure 16) and a second position (as shown
in Figure 17) without disengaging from head portion
372.
[0071] In the first position, as shown in Figure 16, socket
370 fully receives head end
372 and the lowermost edge
375 of socket
370 extends past abutments
374 to define a number of recesses
376 around the circumference of lowermost edge
375.
[0072] Soil displacement member
362 comprises a number of segments
363. Each segment
363 has an outwardly projecting portion
364 which serves to displace soil, as described above in respect of soil displacement
disks
62, and a tab
365 which is received in one of recesses
376. Projections
378, which extend from head end
372 retain segments
363 with their tabs
365 engaged in recesses
376. Segments
363 collectively provide substantially the same function of other soil displacement members,
such as the disks
62 which are described above. While screw
34 is being driven into the ground, fastener
343 holds each socket
370 in its first position. As screw
34 is being driven into the ground the forces on segments
363 tend to hold tabs
365 engaged in recesses
376.
[0073] When screw
34 has been installed to the correct depth then fastener
343 is removed and the upper end of driving tool
332 is pulled axially away from screw
34. As this happens then each of sockets
370 is pulled into its second position, as shown in Figure 17. In the second position,
lower edge
375 is even with, or above, abutments
374 and tabs
365 are no longer coupled to driving tool
332. Segments
363 can therefore fall away. Pins
380 prevent sockets
370 from separating from head portions
372 by bearing against an upper set of abutments
377 which project from head end
372. Shaft
333 remains connected to lead section
330.
[0074] Those skilled in the art will realize that sockets
370 could be coupled to head portions
372 in many ways which allows limited motion between a first position in which segments
363 are retained and a second position in which segments
363 are released.
[0075] As will be apparent to those skilled in the art in the light of the foregoing disclosure,
many alterations and modifications are possible in the practice of this invention.
Accordingly, the scope of the invention is to be construed in accordance with the
substance defined by the following claims.
1. A method for forming a pile, the method comprising:
providing a screw pier (300) having a lead section (330), the lead section (330) comprising
a screw (34) at one end thereof and a soil displacing member (60) spaced apart from
the screw (34);
placing the screw (34) in soil;
coupling a first end of an elongated shaft (132, 333) to the lead section (330), a
second end of the shaft (132, 333) extending away from the lead section (330);
rotating the screw (34) and thereby causing the screw (34) to move through the soil
and propel the soil displacing member (60) through the soil, thereby clearing soil
from a cylindrical region surrounding the shaft (132, 333);
filling the cylindrical region with a fluid grout, either during or after clearing
soil from the cylindrical region surrounding the drive tool (332); and,
allowing the fluid grout in the cylindrical region to solidify and encase the shaft
(132, 333) in a protective layer of solidified grout;
characterized by:
rotating the screw (34) comprises coupling a first end of an elongated drive tool
(332) to the lead section (330) with the shaft (132, 333) extending through an elongated
bore (328) in the drive tool (332) and the drive tool (332) extending through the
cylindrical region, and turning a second end of the drive tool (332) about the elongated
axis of the drive tool (332) so that the drive tool (332) transmits torque directly
to the lead section (330); and,
subsequently uncoupling the first end of the drive tool (332) from the lead section
(330) and withdrawing the drive tool (332) from the cylindrical region prior to allowing
the fluid grout in the cylindrical region to solidify.
2. The method of claim 1, wherein the lead section (330) comprises a lead section head
(341) on an end opposing the screw (34), the first end of the drive tool (332) comprises
a socket (340) and coupling the first end of the drive tool (332) to the lead section
(330) comprises receiving the lead section head (341) in the socket (340).
3. The method of claim 2, wherein the lead section head (341) and an interior of the
socket (340) are both square in cross-section.
4. The method of any one of claims 2 or 3, wherein the shaft (132, 333) comprises a plurality
of sections and the method comprises adding additional sections as the screw moves
through the soil.
5. The method of any one of claims 1, 2, 3 or 4 comprising coupling the second end of
the drive tool (332) to the second end of the shaft (132, 333) prior to turning the
second end of the drive tool (332) about the elongated axis of the drive tool (332).
6. The method of any of claims 1, 2, 3, 4 or 5, wherein rotating the screw (34) comprises
transmitting additional torque through the shaft (132, 333) to the lead section (330)
wherein an amount of torque transmitted through the drive tool (332) to the lead section
(330) is greater than an amount of additional torque transmitted through the shaft
(132, 333) to the lead section (330).
7. The method of any one of claims 1, 2, 3, 4, 5 or 6, comprising mounting one or more
additional soil displacing members (62, 362) at spaced apart locations along the drive
tool (332).
8. The method of claim 7 comprising detaching the one or more additional soil displacing
members (62, 362) from the drive tool (332) prior to or during withdrawing the drive
tool (332) from the cylindrical region.
9. The method of any one of claims 7 or 8, wherein the one or more additional soil displacing
members (62, 362) have diameters larger than a diameter of the soil displacing member
(60) and rotating the screw (34) comprises pulling the additional soil displacing
members (62, 362) through the soil to increase a diameter of the cylindrical region.
10. The method of any one of claims 1, 2, 3, 4, 5 or 6, comprising mounting a plurality
of additional soil displacing members (62, 362) at spaced apart locations along the
drive tool (332), the additional soil displacing members (62, 362) having diameters
larger than the diameter of the soil displacing member (60), the diameters of the
additional soil displacing members (62, 362) farther from the screw (34) being greater
than the diameters of the additional soil displacing members (62, 362) nearer to the
screw (34) and wherein rotating the screw (34) comprises pulling the additional soil
displacing members (62, 362) through the soil to increase a diameter of the cylindrical
region in a stepwise fashion.
11. The method of any one of claims 1,2,3,4, 5,6,7, 8, 9 or 10, comprising:
removing soil from a volume (102) surrounding the screw (34) by rotating the screw
(34) in a first angular direction while restraining the shaft (132, 333) from moving
along its elongated axis; and,
forcing fluid grout under pressure into the volume (102) and allowing the grout in
volume (102) to harden, thereby encasing surfaces of the screw (34) in a protective
layer of solidified grout.
12. The method of claim 11, wherein rotating the screw (34) in the first angular direction
while restraining the shaft (132, 333) comprises rotating the second end of the drive
tool (332) about the elongated axis of the drive tool (332) and thereby transmitting
torque through the drive tool (332) to the lead section (330).
13. The method of claim11, wherein rotating the screw (34) in the first angular direction
while restraining the shaft (132, 333) comprises rotating the second end of the shaft
(132,333) about the elongated axis of the shaft (132, 333) and thereby transmitting
torque through the shaft (132, 333) to the lead section (330).
14. The method of any one of claims 11, 12 or 13, wherein forcing fluid grout under pressure
into the volume (102) comprises rotating the screw (34) as the fluid grout is forced
into the volume (102).
15. The method of any one of claims 11, 12, 13 or 14, wherein forcing fluid grout under
pressure into the volume (102) comprises forcing the fluid grout under pressure through
a longitudinal channel (100) within the shaft (132, 333) and into a longitudinal channel
in the lead section (330) and directing the fluid grout into the volume (102) through
apertures (106) in a wall of the lead section (330).
16. The method of any one of claims 11,12, 13, 14 or 15 comprising, before removing soil
from the volume (102), loosening the soil in the volume (102) by repeatedly rotating
the screw (34) through one or more revolutions and then reversing a direction of rotation
of the screw (34).
17. The method of any one of claims 11,12, 13, 14, 15 or 16, wherein the screw (34) comprises
at least one tab (111) projecting radially outwardly from an outer edge of the screw
(34), the tab (111) loosening soil in a cylindrical shell around the screw (34) and
wherein forcing fluid grout under pressure into the volume (102) comprises allowing
the fluid grout to flow through the cylindrical shell around outer edges of the screw
(34).
18. The method any one of claims 11, 12, 13, 14, 15,16 or 17 wherein rotating the screw
(34) in the first angular direction while restraining the shaft (132, 333) tends to
displace soil from the volume (102) toward the soil displacing member (60).
19. The method of claim 18, wherein the soil displacing member (60) comprises at least
one angled paddle (110) and removing soil from the volume (102) surrounding the screw
(34) comprises rotating the soil displacing member (60) in the first angular direction,
such that rotation of the angled paddle (110) pushes the soil displaced toward the
soil displacing member (60) by the screw (34) radially outwardly.
20. The method of any one of claims 18 or 19, wherein the soil displacing member (60)
is located no more than about 20 cm from the screw (34).
21. A screw pier (300) for making a grout encased pile, the screw pier (300) comprising:
(a) a lead section (330) comprising a screw (34) and a soil displacement member (60)
connected to and spaced apart from the screw (34);
(b) an elongated shaft (132, 333) having a first end coupled to the lead section (330)
and a second end extending away from the lead section (330);
characterized by:
(c) an elongated tubular drive tool (332) having a bore (328), the drive tool having
a first end shaped to be drivingly engageable with and detachable from the lead section
(330) and a second end, the elongated shaft (132, 133) extending through the bore
(328), wherein when the first end of the drive tool (332) is drivingly engaged to
the lead section (330), torque may be transmitted from the second end of the drive
tool (332) directly to the lead section (330) by rotating the second end of drive
tool (332).
22. The screw pier of claim 21, wherein the lead section (330) comprises a lead section
head (341) on an end opposing the screw (34) and the first end of the drive tool (332)
comprises a socket (340), the lead section head (341) insertable into the socket (340)
to drivingly engage the first end of the drive tool (332) with the lead section (330).
23. The screw pier of claim 22, wherein a fit of the lead section head (341) into the
socket (340) is a loose fit, such that the first end of the drive tool (332) is detachable
from the lead section (330).
24. The screw pier of any one of claims 22 or 23, wherein an interior of the socket (340)
and the lead section head (341) are both square in cross-section.
25. The screw pier of any one of claims 21, 22, 23 or 24 comprising a detachable fastener
(343) which couples the second end of the shaft (132, 333) to the second end of the
drive tool (332).
26. The screw pier of any one of claims 21, 22, 23, 24 or 25 comprising a means (72) for
rotating the second end of the drive tool (332) to apply torque to the second end
of the drive tool (332).
27. The screw pier of any one of claims 21, 22, 23, 24, 25 or 26 comprising one or more
additional soil displacing members (62, 362) detachably mounted at spaced apart locations
along the drive tool (332).
28. The screw pier of claim 27, wherein the one or more additional soil displacement members
(62, 362) each comprise a plurality of segments (363), each segment (363) comprising
an outwardly projecting portion (364) and a tab portion (365).
29. The screw pier of claim 28, wherein the drive tool (332) comprises two or more sections
(331, 336) connected by one or more joints and each joint comprises a head end (342,
372) of one drive tool section (331, 336) received in a socket (340A, 370) at an end
of another drive tool section (331, 336), the socket (340A, 370) movable longitudinally
relative to the head end (342, 372) between first and second positions, wherein, when
the socket (340A, 370) is in the first position, an edge (375) of the socket (340A,
370) projects past an abutment (374) on the head end (342, 372) to provide a recess
(376), the recess (376) capable of receiving tab portions (365) of the segments (363)
and, when the socket (340A, 370) is in the second position, the edge (375) of the
socket (340A, 370) is retracted, thereby releasing the tab portions (365) of the segments
(363).
30. The screw pier of any one of claims 27, 28 or 29, wherein the soil displacement member
(60) has a diameter smaller than a diameter of the screw (34) and the one or more
additional soil displacing members (62, 362) have diameters larger than the soil displacing
member (60), the additional soil displacing members (62, 362) further from the screw
(34) having larger diameters than the additional soil displacing members (62, 362)
nearer to the screw (34).
31. The screw pier of any one of claims 21, 22, 23, 24, 25, 26, 27, 28, 29 or 30 comprising
a channel (100) extending through the shaft (132, 333) and into the lead section (330)
and one or more apertures (106) extending through a wall of the lead section (330),
the channel (100) in fluid communication with the apertures (106).
32. The screw pier of any one of claims 21, 22, 23, 24, 25, 26, 27, 28, 29, 30 or 31 wherein
the screw (34) comprises at least one tab (111) projecting radially outwardly from
the peripheral edge of the screw (34).
33. The screw pier of any one of claims 21, 22, 23, 24, 25, 26, 27, 28, 29, 30 or 31,
wherein the peripheral edge of the screw (34) is notched.
34. The screw pier of any one of claims 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32
or 33 wherein the shaft (132, 333) comprises a plurality of elongated sections (324)
coupled together.
35. The screw pier of claim 34, wherein the elongated sections (324) are coupled to one
another by screwing them together.
36. The screw pier of any one of claims 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32,
33, 34 or 35 wherein the drive tool (332) comprises a plurality of elongated sections
(331, 336) coupled together.
37. The screw pier of claim 36, wherein each elongated section (331, 336) of the drive
tool (332) comprises a head (342) at one end and a socket (340A) at an opposing end
thereof, and the elongated sections (331, 336) are coupled to one another by inserting
the head (342) of one section (331, 336) into the socket (340A) of an adjacent section
(336).
1. Verfahren zum Herstellen eines Pfahls bzw. Ortbetonpfahls, mit den folgenden Verfahrensschritten:
Bereitstellen einer Schraubensäule (300) mit einem Führungsabschnitt (330), wobei
der Führungsabschnitt (330) an einem Ende davon ein Schraubengewinde (34) und ein
Bodenverdrängungselement (60) in einem Abstand von dem Schraubengewinde (34) aufweist;
Einbringen des Schraubengewindes (34) in den Boden;
Ankuppeln eines ersten Endes einer verlängerten Welle (132, 333) an den Führungsabschnitt
(330), wobei ein zweites Ende der Welle (132, 333) sich von dem Führungsabschnitt
(330) weg erstreckt;
Drehen des Schraubengewindes (34) und dadurch Bewirken einer Bewegung des Schraubengewindes
(34) durch den Boden hindurch und eines Vorantreibens des Bodenverdrängungselements
(60) durch den Boden hindurch, wodurch Boden aus einem die Welle (132, 333) umgebenden
zylindrischen Bereich verdrängt wird;
Füllen des zylindrischen Bereichs mit einem flüssigen Mörtel entweder während oder
nach dem Verdrängen von Boden aus dem das Antriebswerkzeug (332) umgebenden zylindrischen
Bereich; und
Ermöglichen eines Verfestigens des flüssigen Mörtels in dem zylindrischen Bereich
und Ummantelns der Welle (132, 333) in einer Schutzschicht aus verfestigtem Mörtel;
dadurch gekennzeichnet, dass der Verfahrensschritt Drehen des Schraubengewindes (34) die folgenden Teilschritte
aufweist:
Ankuppeln eines ersten Endes eines länglichen Antriebswerkzeugs (332) an den Führungsabschnitt
(330), wobei die Welle (132, 333) sich durch eine längliche Bohrung (328) in dem Antriebswerkzeug
(332) hindurch erstreckt, und sich das Antriebswerkzeug (332) durch den zylindrischen
Bereich hindurch erstreckt, und
Drehen eines zweiten Endes des Antriebswerkzeug (332) um die verlängerte Achse des
Antriebswerkzeug (332), so dass das Antriebswerkzeug (332) ein Drehmoment direkt auf
den Führungsabschnitt (330) überträgt; und
danach Abkuppeln des ersten Endes des Antriebswerkzeugs (332) von dem Führungsabschnitt
(330) vor dem Ermöglichen eines Verfestigens des flüssigen Mörtels in dem zylindrischen
Bereich.
2. Verfahren nach Anspruch 1, wobei der Führungsabschnitt (330) einen Führungsabschnittskopf
(341) an einem dem Schraubengewinde (34) gegenüberliegenden Ende aufweist, wobei das
erste Ende des Antriebswerkzeugs (332) einen Sockel (340) aufweist und das erste Ende
des Antriebswerkzeugs (332) an den Führungsabschnitt (330) durch Aufnehmen des Führungsabschnittskopfes
(341) in den Sockel (340) ankuppelt.
3. Verfahren nach Anspruch 2, wobei der Führungsabschnitt (341) und ein Inneres des Sockels
(340) beide einen quadratischen Querschnitt aufweisen.
4. Verfahren nach einem der Ansprüche 2 oder 3, wobei die Welle (132, 333) eine Vielzahl
von Abschnitten aufweist und das Verfahren den Teilschritt Anfügen von zusätzlichen
Abschnitten bei Bewegung des Schraubengewindes durch den Boden aufweist.
5. Verfahren nach einem der Ansprüche 1, 2, 3 oder 4, mit dem Teilschritt Ankuppeln des
zweiten Endes des Antriebswerkzeugs (332) an das zweite Ende der Welle (132, 333)
vor dem Verfahrensschritt Drehen des zweiten Endes des Antriebswerkzeugs (332) um
die verlängerte Achse des Antriebswerkzeugs (332).
6. Verfahren nach einem der Ansprüche 1, 2, 3, 4 oder 5, wobei der Verfahrensschritt
Drehen des Schraubengewindes (34) Übertragen von zusätzlichem Drehmoment durch die
Welle (132, 333) auf den Führungsabschnitt (330) aufweist, wobei ein Betrag des durch
das Antriebswerkzeug (332) auf den Führungsabschnitt (330) übertragenen Drehmoments
größer ist als ein Betrag von durch die Welle (132, 333) auf den Führungsabschnitt
(330) übertragenen zusätzlichen Drehmoments.
7. Verfahren nach einem der Ansprüche 1, 2, 3, 4, 5 oder 6, mit dem Teilschritt Aufbringen
von einem oder mehreren zusätzlichen Bodenverdrängungselementen (62, 362) an mit Abständen
voneinander entfernt liegenden Stellen längs des Antriebswerkzeugs (332).
8. Verfahren nach Anspruch 7, mit dem Teilschritt Entfernen des einen oder der mehreren
Bodenverdrängungselemente (62, 362) von dem Antriebswerkzeugs (332) vor oder während
des Zurückziehens des Antriebswerkzeugs (332) aus dem zylindrischen Bereich.
9. Verfahren nach Anspruch 7 oder 8, wobei das eine oder die mehreren Bodenverdrängungselemente
(62, 362) Durchmesser aufweisen, welche größer sind als ein Durchmesser des Bodenverdrängungselements
(60), und wobei der Verfahrensschritt Drehen des Schraubengewindes (34) den Teilschritt
Ziehen der zusätzlichen Bodenverdrängungselemente (62, 362) durch den Boden hindurch
zur Vergrößerung eines Durchmesser des zylindrischen Bereichs aufweist.
10. Verfahren nach einem der Ansprüche 1, 2, 3, 4, 5 oder 6, mit dem Teilschritt Aufbringen
von einer Vielzahl von zusätzlichen Bodenverdrängungselementen (62, 362) an mit Abständen
voneinander entfernt liegenden Stellen längs des Antriebswerkzeugs (332), wobei die
zusätzlichen Bodenverdrängungselemente (62, 362) größere Durchmesser, als der Durchmesser
des Bodenverdrängungselements (60) beträgt, aufweisen, wobei die Durchmesser der zusätzlichen
Bodenverdrängungselemente (62, 362), welche weiter von dem Schraubengewinde (34) entfernt
sind, größer sind als die Durchmesser der zusätzlichen Bodenverdrängungselemente (62,
362), welche näher an dem Schraubengewinde (34) angeordnet sind, und wobei der Verfahrensschritt
Drehen des Schraubengewindes (34) den Teilschritt Ziehen der zusätzlichen Bodenverdrängungselemente
(62, 362) durch den Boden hindurch zur Vergrößerung eines Durchmesser des zylindrischen
Bereichs in einer stufenförmigen Art und Weise aufweist.
11. Verfahren nach einem der Ansprüche 1, 2, 3, 4, 5, 6, 7, 8, 9 oder 10, mit den V erfahrensschri
tten:
Entfernen von Boden aus einem das Schraubengewinde (34) umgebenden Volumen (102) durch
Drehen des Schraubengewindes (34) in einer ersten Winkelrichtung bei Zurückhalten
der Welle (132, 333) von der Bewegung entlang ihrer verlängerten Achse; und
Pressen von flüssigem Mörtel unter Druck in das Volumen (102) und Ermöglichen des
Verfestigens des Mörtels in dem Volumen (102), wodurch die Oberflächen des Schraubengewindes
(34) durch eine Schutzschicht aus verfestigtem Mörtel ummantelt werden.
12. Verfahren nach Anspruch 11, wobei der Verfahrensschritt Drehen des Schraubengewindes
(34) in einer ersten Winkelrichtung mit Zurückhalten der Welle (132, 333) den Teilschritt
Drehen des zweiten Endes des Antriebswerkzeugs (332) um die verlängerte Achse des
Antriebswerkzeugs (332) und dadurch Übertragen von Drehmoment durch das Antriebswerkzeugs
(332) auf den Führungsabschnitt (330) aufweist.
13. Verfahren nach Anspruch 11, wobei der Verfahrensschritt Drehen des Schraubengewindes
(34) in einer ersten Winkelrichtung mit Zurückhalten der Welle (132, 333) den Teilschritt
Drehen des zweiten Endes der Welle (132, 333) um die verlängerte Achse der Welle (132,
333) und dadurch Übertragen von Drehmoment durch die Welle (132, 333) auf den Führungsabschnitt
(330) aufweist.
14. Verfahren nach einem der Ansprüche 11, 12 oder 13, wobei der Verfahrensschritt Pressen
von flüssigem Mörtel unter Druck in das Volumen (102) den Teilschritt Drehen des Schraubengewindes
(34) aufweist, wenn der flüssige Mörtel in das Volumen (102) gepresst wird.
15. Verfahren nach einem der Ansprüche 11, 12, 13 oder 14, wobei der Verfahrensschritt
Pressen von flüssigem Mörtel unter Druck in das Volumen (102) den Teilschritt Pressen
von flüssigem Mörtel unter Druck durch einen länglichen Kanal (100) innerhalb der
Welle (132, 333) und in einen länglichen Kanal in dem Führungsabschnitt (330) und
Leiten des flüssigen Mörtels in das Volumen (102) durch Öffnungen (106) in einer Wand
des Führungsabschnitts (330) aufweist.
16. Verfahren nach einem der Ansprüche 11, 12, 13, 14 oder 15, welches vor dem Verfahrensschritt
Entfernen von Boden aus dem Volumen (102) den Teilschritt Lockern des Bodens in dem
Volumen (102) durch wiederholtes Drehen des Schraubengewindes (34) durch eine oder
mehrere Umdrehungen und dann Umkehren einer Drehrichtung des Schraubengewindes (34)
aufweist.
17. Verfahren nach einem der Ansprüche 11, 12, 13, 14, 15 oder 16, wobei das Schraubengewinde
(34) mindestens eine von einer äußeren Kante des Schraubengewindes (34) radial nach
außen gerichtet hervorstehende Nase (111) aufweist, wobei die Nase (111) Boden in
einer zylindrischen Hülle um das Schraubengewinde (34) herum lockert, und wobei der
Verfahrensschritt Pressen von flüssigem Mörtel unter Druck in das Volumen (102) den
Teilschritt Ermöglichen von Fließen des flüssigen Mörtels durch die zylindrische Hülle
um äußere Kanten des Schraubengewindes (34) herum aufweist.
18. Verfahren nach einem der Ansprüche 11, 12, 13, 14, 15, 16 oder 17, wobei der Verfahrensschritt
Drehen des Schraubengewindes (34) in einer ersten Winkelrichtung mit Zurückhalten
der Welle (132, 333) dazu tendiert, Boden aus dem Volumen (102) gegen das Bodenverdrängungselement
(60) zu verschieben.
19. Verfahren nach Anspruch 18, wobei das Bodenverdrängungselement (60) mindestens eine
winklige Schaufel (110) aufweist, und der Verfahrensschritt Entfernen von Boden aus
dem das Schraubengewinde (34) umgebenden Volumen (102) den Teilschritt Drehen des
Bodenverdrängungselements (60) in der ersten Winkelrichtung aufweist, so dass Drehen
der winkligen Schaufel (110) den von dem Schraubengewinde (34) gegen das Bodenverdrängungselement
(60) verschobenen Boden radial nach außen schiebt.
20. Verfahren nach einem der Ansprüche 18 oder 19, wobei das Bodenverdrängungselement
(60) nicht mehr als 20 cm von dem Schraubengewinde (34) entfernt angeordnet ist.
21. Schraubensäule (300) zur Erstellung eines mit Mörtel ummantelten Pfahls, wobei die
Schraubensäule (300) Folgendes aufweist:
a) einen Führungsabschnitt (330) mit einem Schraubengewinde (34) und einem Bodenverdrängungselement
(60), welche mit dem Schraubengewinde (34) verbunden und in einem Abstand von dieser
angeordnet ist;
b) eine verlängerte Welle (132, 333) mit einem ersten an den Führungsabschnitt (330)
angekuppelten Ende und mit einem zweiten sich von dem Führungsabschnitt (330) weg
erstreckenden Ende;
gekennzeichnet durch:
c) ein längliches röhrenförmiges Antriebswerkzeug (332) mit einer Bohrung (328), wobei
das Antriebswerkzeug ein erstes Ende aufweist, welches so ausgebildet ist, dass es
beim Antreiben mit dem Führungsabschnitt (330) in Eingriff steht und von diesem lösbar
ist, und ein zweites Ende aufweist, wobei die verlängerte Welle (132, 333) sich durch die Bohrung (328) hindurch erstreckt, wobei durch Drehen des zweiten Endes des Antriebswerkzeugs (332) Drehmoment von dem zweiten Ende
des Antriebswerkzeugs (332) direkt auf den Führungsabschnitt (330) übertragbar ist,
wenn das erste Ende des Antriebswerkzeugs (332) zum Antreiben mit dem Führungsabschnitt
in Eingriff ist.
22. Schraubensäule nach Anspruch 21, wobei der Führungsabschnitt (330) einen Führungsabschnittskopf
(341) an einem dem Schraubengewinde (34) gegenüberliegenden Ende aufweist, und das
erste Ende des Antriebswerkzeugs (332) einen Sockel (340) aufweist, wobei der Führungsabschnittskopf
(341) in den Sockel (340) einsetzbar ist, um das erste Ende des Antriebswerkzeugs
(332) mit dem Führungsabschnitt (330) zum Antrieb in Eingriff zu bringen.
23. Schraubensäule nach Anspruch 22, wobei der Sitz des Führungsabschnittskopfs (341)
ein loser Sitz ist, so dass das erste Ende des Antriebswerkzeugs (332) von dem Führungsabschnitt
(330) abnehmbar ausgebildet ist.
24. Schraubensäule nach einem der Ansprüche 22 oder 23, wobei ein Inneres des Sockels
(340) und der Führungsabschnittskopf (341) beide mit einem quadratischen Querschnitt
ausgebildet sind.
25. Schraubensäule nach einem der Ansprüche 21, 22, 23 oder 24, mit einem abnehmbaren
Verbindungselement (343), welches das zweite Ende der Welle (132, 333) an das zweite
Ende des Antriebswerkzeug (332) ankuppelt.
26. Schraubensäule nach einem der Ansprüche 21, 22, 23, 24 oder 25, mit einer Einrichtung
(72) zum Drehen des zweiten Endes des Antriebswerkzeugs (332) zum Aufbringen von Drehmoment
auf das zweite Ende des Antriebswerkzeugs (332).
27. Schraubensäule nach einem der Ansprüche 21, 22, 23, 24, 25 oder 26, mit einem oder
mit mehreren zusätzlichen Bodenverdrängungselementen (62, 362), welche abnehmbar in
Abständen zueinander längs des Antriebswerkzeugs (332) angeordnet sind.
28. Schraubensäule nach Anspruch 27, wobei das eine oder die mehreren zusätzlichen Bodenverdrängungselemente
(62, 362) jede eine Vielzahl von Segmenten (363) aufweist, wobei jedes Segment (363)
einen nach außen vorstehenden Abschnitt (364) und einen Laschenabschnitt (365) aufweist.
29. Schraubensäule nach Anspruch 28, wobei das Antriebswerkzeug (332) zwei oder mehr Abschnitte
(331, 336) aufweist, welche mit einer oder mit mehreren Verbindungen verbunden sind,
und jede Verbindung ein Kopfende (342, 372) eines Antriebswerkzeugabschnitts (331,
336) aufweist, welches in einem Sockel (340A, 370) an einem Ende eines weiteren Antriebswerkzeugabschnitts
(331, 336) aufgenommen ist, wobei der Sockel (340A, 370) längsbeweglich relativ zu
dem Kopfende (342, 372) zwischen ersten und zweiten Stellungen ausgebildet ist, wobei,
wenn der Sockel (340A, 370) sich in der ersten Stellung befindet, eine Kante (375)
des Sockels (340A, 370) an einem Widerlager (374) an dem Kopfende (342, 372) vorbei
hervorsteht, um eine Aussparung (376) zu bilden, wobei die Aussparung (376) geeignet
ist, die Laschenabschnitte (365) der Segmente (363) aufzunehmen, und wobei, wenn der
Sockel (340A 370) sich in der zweiten Stellung befindet, die Kante (375) des Sockels
(340A, 370) zurückgezogen ist, wodurch die Laschenabschnitte (365) der Segmente (363)
gelöst werden.
30. Schraubensäule nach einem der Ansprüche 27, 28 oder 29, wobei das Bodenverdrängungselement
(60) einen Durchmesser aufweist, welcher kleiner als der Durchmesser des Schraubengewindes
(34) ist, und das eine oder die mehreren zusätzlichen Bodenverdrängungselemente (62,
362) Durchmesser aufweisen, welche größer als die Bodenverdrängungselemente (60) sind,
wobei die weiter von dem Schraubengewinde (34) entfernten zusätzlichen Bodenverdrängungselemente
(62, 362) größere Durchmesser aufweisen als die an dem Schraubengewinde (34) näher
angeordneten zusätzlichen Bodenverdrängungselemente (62, 362).
31. Schraubensäule nach einem der Ansprüche 21, 22, 23, 24, 25, 26, 27, 28, 29 oder 30,
mit einem sich durch die Welle (123, 333) hindurch und in den Führungsabschnitt (330)
erstreckenden Kanal (100), und mit einer oder mit mehreren Öffnungen (106), welche
sich durch eine Wand des Führungsabschnitts (330) hindurch erstrecken, wobei der Kanal
(100) mit den Öffnungen (106) für flüssige Stoffe in Verbindung steht.
32. Schraubensäule nach einem der Ansprüche 21, 22, 23, 24, 25, 26, 27, 28, 29, 30 oder
31, wobei das Schraubengewinde (34) mindestens eine radial von dem peripheren Rand
nach außen vorstehende Nase (111) aufweist.
33. Schraubensäule nach einem der Ansprüche 21, 22, 23, 24, 25, 26, 27, 28, 29, 30 oder
31, wobei der periphere Rand des Schraubengewindes (34) eingekerbt ist.
34. Schraubensäule nach einem der Ansprüche 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31,
32 oder 33, wobei die Welle (123, 333) eine Vielzahl von miteinander gekuppelten länglichen
Abschnitten (324) aufweist.
35. Schraubensäule nach Anspruch 34, wobei die länglichen Abschnitte (324) aneinander
gekuppelt sind, indem sie zusammengeschraubt sind.
36. Schraubensäule nach einem der Ansprüche 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31,
32, 33, 34 oder 35, wobei das Antriebswerkzeug (332) eine Vielzahl von miteinander
gekuppelten länglichen Abschnitten (331, 336) aufweist.
37. Schraubensäule nach Anspruch 36, wobei jeder längliche Abschnitt (331, 336) des Antriebswerkzeugs
(332) einen Kopf (342) an einem Ende und einen Sockel (340A) an einem davon gegenüberliegenden
Ende aufweist, und wobei die länglichen Abschnitte (331, 336) durch Einsetzen des
Kopfes (342) eines Abschnitts (331, 336) in den Sockel (340A) eines angrenzenden Abschnitts
(336) miteinander gekuppelt sind.
1. Procédé de formation d'une pile, le procédé comprenant les étapes consistant à:
prévoir un pieu à vis (300) comportant une partie d'attaque (330), la partie d'attaque
(330) comprenant une vis (34) à une extrémité, et un élément chasse-sol (60) situé
à distance de la vis (34) ;
mettre en place la vis (34) dans le sol ;
accoupler une première extrémité d'une tige allongée (132, 333) à la partie d'attaque
(330), une seconde extrémité de la tige (132, 333) s'étendant dans le sens opposé
à la partie d'attaque (330) ;
mettre en rotation la vis (34) pour ainsi provoquer l'avancement de la vis (34) à
travers le sol et la propulsion de l'élément chasse-sol (60) à travers le sol, pour
ainsi évacuer le sol d'une zone cylindrique entourant la tige (132, 333) ;
remplir la zone cylindrique par un ciment fluide, soit pendant soit après l'évacuation
du sol hors de la zone cylindrique entourant l'outil de fonçage (332) ; et
permettre le ciment fluide, dans la zone cylindrique, de solidifier pour qu'il enrobe
la tige (132,333) d'une couche protectrice de ciment solidifié;
caractérisé en ce que :
la mise en rotation de la vis (34) comprend l'accouplement d'une première extrémité
d'un outil allongé de fonçage (332) à la partie d'attaque (330), par la tige (132,
333) qui passe dans un alésage allongé (328) ménagé dans l'outil de fonçage (332),
l'outil de fonçage (332) s'étendant dans la zone cylindrique, et la rotation d'une
seconde extrémité de l'outil de fonçage (332) autour de l'axe allongé de l'outil de
fonçage (332), de telle sorte que l'outil de fonçage (332) transmette directement
un couple à la partie d'attaque (330) ; et
la première extrémité de l'outil de fonçage (332) est ensuite désaccouplée par rapport
à la partie d'attaque (330), et extraire l'outil de fonçage (332) de la zone cylindrique
avant de laisser le ciment fluide se solidifier dans la zone cylindrique.
2. Procédé selon la revendication 1, dans lequel la partie d'attaque (330) comprend une
tête de partie d'attaque (341) située à une extrémité à l'opposé de la vis (34), la
première extrémité de l'outil de fonçage (332) comprenant un manchon (340), et dans
lequel l'accouplement de la première extrémité de l'outil de fonçage (332) à la partie
d'attaque (330) comprend le logement de la tête de partie d'attaque (341) dans le
manchon (340).
3. Procédé selon la revendication 2, dans lequel la tête de partie d'attaque (341) et
l'intérieur du manchon (340) ont tous les deux une section transversale carrée.
4. Procédé selon l'une des revendications 2 ou 3, dans lequel la tige (132, 333) comprend
une pluralité de tronçons, et dans lequel le procédé comprend l'ajout de tronçons
supplémentaires au fur et à mesure que la vis se déplace à travers le sol.
5. Procédé selon l'une quelconque des revendications 1, 2, 3 ou 4, comprenant l'accouplement
de la seconde extrémité de l'outil de fonçage (332) à la seconde extrémité de la tige
(132, 333) avant de faire tourner la seconde extrémité de l'outil de fonçage (332)
autour de l'axe allongé de l'outil de fonçage (332).
6. Procédé selon l'une quelconque des revendications 1, 2, 3, 4 ou 5, dans lequel la
mise en rotation de la vis (34) comprend la transmission d'un couple supplémentaire,
par l'intermédiaire de la tige (132, 333), à la partie d'attaque (330), et la grandeur
du couple transmis par l'intermédiaire de l'outil de fonçage (332) à la partie d'attaque
(330) étant supérieure à la grandeur du couple supplémentaire, transmis par l'intermédiaire
de la tige (132, 333) à la partie d'attaque (330).
7. Procédé selon l'une quelconque des revendications 1, 2, 3, 4, 5 ou 6, comprenant le
montage d'un seul ou de plusieurs éléments chasse-sol supplémentaires (62, 362) en
des emplacements mutuellement écartés, le long de l'outil de fonçage (332).
8. Procédé selon la revendication 7, comprenant le détachement de l'élément ou des éléments
chasse-sol supplémentaires (62, 362) de l'outil de fonçage (332) avant ou pendant
l'extraction de l'outil de fonçage (332) hors de la zone cylindrique.
9. Procédé selon la revendication 7 ou 8, dans lequel l'élément ou les éléments chasse-sol
supplémentaires (62, 362) présentent des diamètres supérieurs à un diamètre de l'élément
chasse-sol (60), et dans lequel la mise en rotation de la vis (34) comprend le tirage
des éléments chasse-sol supplémentaires (62, 362) à travers le sol afin d'augmenter
un diamètre de la zone cylindrique.
10. Procédé selon l'une quelconque des revendications 1, 2, 3, 4, 5 ou 6, comprenant le
montage d'une pluralité d'éléments chasse-sol supplémentaires (62, 362) en des emplacement
mutuellement écartés le long de l'outil de fonçage (332), ces éléments chasse-sol
supplémentaires (62, 362) ayant des diamètres supérieurs au diamètre de l'élément
chasse-sol (60), et les diamètres des éléments chasse-sol supplémentaires (62, 362),
qui sont plus éloignés par rapport à la vis (34), étant plus grands que les diamètres
des éléments chasse-sol supplémentaires (62, 362) plus proches de la vis (34), et
dans lequel la mise en rotation de la vis (34) comprend le tirage des éléments chasse-sol
supplémentaires (62, 362) à travers le sol afin d'augmenter un diamètre de la zone
cylindrique, d'une façon progressive.
11. Procédé selon l'une quelconque des revendications 1, 2, 3, 4, 5, 6, 7, 8, 9 ou 10,
comprenant :
l'enlèvement du sol à partir d'un espace (102) entourant la vis (34), par la mise
en rotation de la vis (34) dans un premier sens angulaire tout en empêchant la tige
(132, 333) de se déplacer le long de son axe allongé ; et
l'injection de ciment fluide sous pression dans l'espace (102) et le durcissement
du ciment dans cet espace (102), pour ainsi enrober des surfaces de la vis (34) par
une couche protectrice de ciment solidifié.
12. Procédé selon la revendication 11, dans lequel la mise en rotation de la vis (34)
dans le premier sens angulaire tout en retenant la tige (132, 333) comprend la mise
en rotation de la seconde extrémité de l'outil de fonçage (332) autour de l'axe allongé
de l'outil de fonçage (332), pour ainsi transmettre un couple par l'intermédiaire
de l'outil de fonçage (332) à la partie d'attaque (330).
13. Procédé selon la revendication 11, dans lequel la mise en rotation de la vis (34)
dans le premier sens angulaire tout en retenant la tige (132, 333) comprend la mise
en rotation de la seconde extrémité de la tige (132, 333) autour de l'axe allongé
de la tige (132, 333), pour ainsi transmettre un couple par l'intermédiaire de la
tige (132, 333) à la partie d'attaque (330).
14. Procédé selon l'une des revendications 11, 12 ou 13, dans lequel l'injection de ciment
fluide sous pression dans l'espace (102) comprend la mise en rotation de la vis (34)
lorsque le ciment fluide est injecté dans cet espace (102).
15. Procédé selon l'une quelconque des revendications 11, 12, 13 ou 14, dans lequel l'injection
de ciment fluide sous pression dans l'espace (102) comprend l'injection de ciment
fluide sous pression par l'intermédiaire d'un canal longitudinal (100) situé à l'intérieur
de la tige (132, 333) jusque dans un canal longitudinal situé dans la partie d'attaque
(330), et le guidage du ciment fluide vers l'espace (102), par l'intermédiaire d'orifices
(106) ménagés dans une paroi de la partie d'attaque (330).
16. Procédé selon l'une quelconque des revendications 11, 12, 13, 14 ou 15, comprenant,
avant l'enlèvement du sol à partir de l'espace (102), l'ameublissement du sol dans
l'espace (102), en faisant tourner de manière répétée la vis (34) sur un ou plusieurs
tours complets et en inversant ensuite le sens de rotation de la vis (34).
17. Procédé selon l'une quelconque des revendications 11, 12, 13, 14, 15 ou 16, dans lequel
la vis (34) comprend au moins une patte (111) faisant radialement saillie vers l'extérieur
à partir d'un bord extérieur de la vis (34), la patte (111) ameublissant le sol dans
une enveloppe cylindrique autour de la vis (34), et dans lequel l'injection de ciment
fluide sous pression dans l'espace (102) comprend l'écoulement du ciment fluide à
travers l'enveloppe cylindrique autour des bords extérieurs de la vis (34).
18. Procédé selon l'une quelconque des revendications 11, 12, 13, 14, 15, 16 ou 17, dans
lequel la mise en rotation de la vis (34) dans le premier sens angulaire, tout en
retenant la tige (132, 333) tend à déplacer le sol à partir de l'espace (102) en direction
de l'élément chasse-sol (60).
19. Procédé selon la revendication 18, dans lequel l'élément chasse-sol (60) comprend
au moins une palette inclinée (110), et dans lequel l'enlèvement du sol à partir de
l'espace (102) entourant la vis (34) comprend la mise en rotation de l'élément chasse-sol
(60) dans le premier sens angulaire, de telle sorte que la rotation de la palette
inclinée (110) pousse, radialement vers l'extérieur, le sol déplacé par la vis (34)
en direction de l'élément chasse-sol (60).
20. Procédé selon la revendication 18 ou 19, dans lequel l'élément chasse-sol (60) n'est
pas situé à plus d'environ 20 cm de la vis (34).
21. Pieu à vis (300), destiné à la fabrication d'une pile encaissée dans du ciment, le
pieu à vis (300) comprenant :
(a) une partie d'attaque (330), comportant une vis (34) et un élément chasse-sol (60)
relié à la vis (34) et situé à distance de celle-ci ;
(b) une tige allongée (132, 333), comprenant une première extrémité accouplée à la
partie d'attaque (330), et une seconde extrémité s'étendant dans le sens opposé à
la partie d'attaque (330) ;
caractérisé par :
(c) un outil de fonçage (332), tubulaire et allongé, comportant un alésage (328),
l'outil de fonçage présentant une première extrémité conformée de façon à pouvoir
venir en prise d'entraînement avec la partie d'attaque (330) et à pouvoir en être
séparée, et une seconde extrémité, la tige allongée (132, 333) s'étendant dans l'alésage
(328), et dans lequel, lorsque la première extrémité de l'outil de fonçage (332) est
en prise d'entraînement avec la partie d'attaque (330), un couple peut être transmis
depuis la seconde extrémité de l'outil de fonçage (332) directement à la partie d'attaque
(330), par la mise en rotation de la seconde extrémité de l'outil de fonçage (332).
22. Pieu à vis selon la revendication 21, dans lequel la partie d'attaque (330) comprend
une tête de partie d'attaque (341) située à une extrémité à l'opposé de la vis (34),
et dans lequel la première extrémité de l'outil de fonçage (332) comprend un manchon
(340), la tête de partie d'attaque (341) pouvant être insérée dans le manchon (340)
afin de mettre en prise d'entraînement la première extrémité de l'outil de fonçage
(332) avec la partie d'attaque (330).
23. Pieu à vis selon la revendication 22, dans lequel l'ajustement de la tête de partie
d'attaque (341) dans le manchon (340) est un ajustement libre, de telle sorte que
la première extrémité de l'outil de fonçage (332) puisse être détachée de la partie
d'attaque (330).
24. Pieu à vis selon la revendication 22 ou 23, dans lequel une partie intérieure du manchon
(340) et la tête de partie d'attaque (341) ont toutes les deux une section transversale
carrée.
25. Pieu à vis selon l'une quelconque des revendications 21, 22, 23 ou 24, comprenant
un élément de fixation (343) détachable, qui relie la seconde extrémité de la tige
(132, 333) à la seconde extrémité de l'outil de fonçage (332).
26. Pieu à vis selon l'une quelconque des revendications 21, 22, 23, 24 ou 25, comprenant
un moyen (72) pour la mise en rotation de la seconde extrémité de l'outil de fonçage
(332), afin d'appliquer un couple à la seconde extrémité de l'outil de fonçage (332).
27. Pieu à vis selon l'une quelconque des revendications 21, 22, 23, 24, 25 ou 26, comprenant
un élément ou plusieurs éléments chasse-sol supplémentaires (62, 362), montés de manière
détachable en des emplacements mutuellement écartés le long de l'outil de fonçage
(332).
28. Pieu à vis selon la revendication 27, dans lequel l'élément ou les éléments chasse-sol
supplémentaires (62, 362) comprennent chacun une pluralité de segments (363), chaque
segment (363) comprenant une partie (364) faisant saillie vers l'extérieur et une
partie formant patte (365).
29. Pieu à vis selon la revendication 28, dans lequel l'outil de fonçage (332) comprend
deux tronçons (331, 336) ou davantage, reliés par un ou plusieurs joints, chaque joint
comprenant une extrémité de tête (342, 372) d'un tronçon d'outil de fonçage (331,
336), logée dans un manchon (340A, 370) au niveau d'une extrémité d'un autre tronçon
d'outil de fonçage (331, 336), le manchon (340A, 370) étant mobile longitudinalement
par rapport à l'extrémité de tête (342, 372), entre des première et seconde positions
dans lesquelles, lorsque le manchon (340A, 370) se trouve dans la première position,
un bord (375) du manchon (340A, 370) fait saillie au-delà d'un épaulement de butée
(374) situé sur l'extrémité de tête (342, 372) afin de constituer une cavité (376),
cette cavité (376) étant capable de loger des parties formant pattes (365) des segments
(363) tandis que, lorsque le manchon (340A, 370) est dans la seconde position, le
bord (375) du manchon (340A, 370) est ramené vers l'arrière pour ainsi libérer les
parties formant pattes (365) des segments (363).
30. Pieu à vis selon l'une quelconque des revendications 27, 28 ou 29, dans lequel l'élément
chasse-sol (60) présente un diamètre inférieur à un diamètre de la vis (34), et dans
lequel l'élément ou les éléments chasse-sol supplémentaires (62, 362) ont des diamètres
supérieurs à celui de l'élément chasse-sol (60), les éléments chasse-sol supplémentaires
(62, 362), qui sont plus éloignés par rapport à la vis (34), ayant de plus grands
diamètres que les éléments chasse-sol supplémentaires (62, 362) plus proches de la
vis (34).
31. Pieu à vis selon l'une quelconque des revendications 21, 22, 23, 24, 25, 26, 27, 28,
29 ou 30, comprenant un canal (100) s'étendant à l'intérieur de la tige (132, 333)
jusque dans la partie d'attaque (330), et un ou plusieurs d'orifices (106) traversant
une paroi de la partie d'attaque (330), le canal (100) étant en communication de fluide
avec les orifices (106).
32. Pieu à vis selon l'une quelconque des revendications 21, 22, 23, 24, 25, 26, 27, 28,
29, 30 ou 31, dans lequel la vis (34) comprend au moins une patte (111) faisant radialement
saillie vers l'extérieur à partir du bord périphérique de la vis (34).
33. Pieu à vis selon l'une quelconque des revendications 21, 22, 23, 24, 25, 26, 27, 28,
29, 30 ou 31, dans lequel le bord périphérique de la vis (34) est entaillé.
34. Pieu à vis selon l'une quelconque des revendications 21, 22, 23, 24, 25, 26, 27, 28,
29, 30, 31, 32 ou 33, dans lequel la tige (132, 333) comprend une pluralité de tronçons
allongés (324) mutuellement assemblés.
35. Pieu à vis selon la revendication 34, dans lequel les tronçons allongés (324) sont
mutuellement assemblés par vissage.
36. Pieu à vis selon l'une quelconque des revendications 21, 22, 23, 24, 25, 26, 27, 28,
29, 30, 31, 32, 33, 34 ou 35, dans lequel l'outil de fonçage (332) comprend une pluralité
de tronçons allongés (331, 336) mutuellement assemblés.
37. Pieu à vis selon la revendication 36, dans lequel chaque tronçon allongé (331, 336)
de l'outil de fonçage (332) comprend une tête (342) à une extrémité et un manchon
(340A) à son extrémité opposée, les tronçons allongés (331, 336) étant reliés les
uns aux autres par introduction de la tête (342) d'un tronçon (331, 336) dans le manchon
(340A) d'un tronçon (336) adjacent.