A method for adjusting the height of and securing a pile or column shaped body, and supporting pile or supporting column adapted for carrying out this method

Abstract

 A flexible bag (8) atthe bottom end of the pile (3) is placed in the hole (2) for the pile (3), which folds around the pile foot. Then the bag is filled with liquid mortar until the required height of the pile upper end is obtained, whereafter the mortar is left to harden. The bag (8) may also be placed between the pile lower end and an auxiliary foot piece (11), particularly when pile (3) and hole (2) are mutually eccentric. The invention also includes piles adapted for carrying out the method.

Description

[0001] A method for adjusting the height of and securing a pile- or column shaped body, and supporting pile or supporting columm adapted for carrying out this method.

[0002] The invention relates to a method for adjusting the height of and securing a pile or column shaped body in a hole provided in the bottom.

[0003] The invention deals particularly with anchoring in the bottom a previously fully finished pile or column shaped body, it'being a condition that this body becomes secured at a predetermined height and at an accurately determined position in the bottom, particularly a stony bottom or rock bottom. It must be kept in mind that it is very difficult to provide the hole serving for receiving the lower portion of that pile or column shaped body, through drilling or another method, so accurately that its bottom is obtained exactly at the desired level. Therefore generally it will be necessary to keep the pile or column shaped body with its lower end spaced from the hole bottom. A known art is to support the body at the desired height level, e.g. with the intermediary of a hoisting apparatus, whereafter the hole around the inserted body is filled up with a hardenable mass. After the hardening of said filling mass the provisional support of the body may be removed.

[0004] It will be clear that this manner of operation is extremely circuitous and time consuming.

[0005] According to the invention this disadvantage is met in that a substantially cylindrical bag of flexible material, closed at both ends, is placed in the hole such that both bag end walls engage at narrow mutual spacing a lower end surface of the body and the hole bottom respectively or. the upper surface of a stationary auxiliary piece, placed on that bottom, while the circumferential wall of the bag is entered in the shape of an axially directed fold in the annular clearance between a circumferential wall portion of the body on the one hand and the circumferential wall of the hole or a circumferential wall portion of the auxiliary piece, placed therein respectively, on the other hand, thereafter the bag is filled under pressure with the liquid and hardenable mass.

[0006] Under the influence of the pressure through which the bag is filled with the liquid and hardenable mass the bag end walls engage the hole bottom and the upper surface of the auxiliary piece respectively, as well as the lower end surface of the body. Simultaneously the pile or column shaped body is pushed upwardly while the bag is filled. The filling may be continued until it is established that the correct level of the body has been reached. During this adjusting movement the axial bag wall fold substantially frictionless unrolls in the annular clearance so that the bag material, apart from by the filling pressure, is not exposed to uncontrollable loads.

[0007] Preferably as the liquid and hardenable mass a hydraulic mortar is used, while a bag is applied having water permeable walls. This offers the possibility to apply a mortar having a high water-cement factor which therefore may be easily entered. Under the influence of the filling pressure the water is then pressed outwardly through the bag walls, whereby the water-cement factor decreases, the hardening process is furthered and a filling body of good quality is obtained as determined by the lower water-cement factor.

[0008] The simplest method of operation is that in which the bag is secured with its upper end wall to the lower end of the pile or column shaped body and the bag is lowered together with this body to the desired height in- the hole, whereby the bag directly engages the hole bottom, while the axial bag wall fold enters upwardly directed between the circumferential wall of the hole and the outer circumferential wall of the pile or column shaped body. When filling the bag the pile or column shaped body will automatically take a central position with respect to the hole. This may be a disadvantage, namely when the position of the hole does not accurately correspond to the desired position and therefore it is important that the pile or column shaped body is anchored in an eccentric position with respect to the hole.

[0009] In such a case it is preferable to place an auxiliary piece on the hole bottom which may extend with an annular clearance into a hole provided in the lower portion of the pile or column shaped body. The axial bag wall fold then assumes a position downwardly directed into the annular clearance, said clearance then being delimited by the circumferential wall of the hole in the body and the outer circumferential surface of the auxiliary piece. By this method of operation the bag will not tend during its filling to push the pile or column shaped body laterally from its provisional position in the hole.

[0010] The invention also relates to a supporting pile or supporting column which is suitable for carrying out the above described method, the bag constituting an inherent portion thereof.

[0011] The supporting pile or supporting column proposed by the invention is therefore characterized by a foot which is axially movable with respect to the pile or column shaped body, said foot being received in the manner of a plunger in a cylinder volume present in the lower end of the pile or column body, a substantially cylindrical bag of flexible material, clos-ed_" at both ends, being also provided in the cylinder volume, such that both end walls are present between the cylinder bottom and the inwardly facing end surface of the plunger, the circumferential wall of the bag lying in the shape of an axial fold in the annular clearance between the cylinder wall and the plunger.

[0012] The invention is hereunder illustrated with reference to the drawing of two embodiments, given as examples.

Figure 1 shows a schematic vertical cross-section through a hole in the bottom and through a supporting column placed therein by application of the method according to the invention;

Figure 2 shows a similar vertical cross-section as Figure 1, but in which the supporting column has been shown in a preferred embodiment, and

Figure 3 shows in vertical section the connection between the bag and the passage extending in longitudinal direction through the supporting column.

Figure 1 and 2 show the bottom 1 which has a solid structure, particularly a rocky structure. In this bottom the hole 2 has been provided, e.g. by drilling. The depth of this hole is e.g. 8 meters.

[0013] In this hole 2 the concrete supporting column, indicated 3 in Figure 1 and 3' in Figure 2 respectively, has to be placed. Said supporting column may belong to a series of similar supporting columns of which the upper end surfaces have to serve jointly as the supporting surface for prefabricated horizontal structural parts. Therefore it is important that the upper end surface of each supporting column is placed accurately at a predetermined height. It is very difficult, if not impossible, to provide the hole 2 with the required accuracy with the corresponding depth. Therefore, when applying the method according to the invention, the hole 2 is in any case made somewhat deeper than corresponding to the desired height of the end surface of the supporting column.

[0014] In the embodiment according to Figure 1 the operation is such that the vertical clearance between the bottom 4 of the hole 2 and the lower end surface 5 of the column 3, placed in the hole by means of a crane, is filled with liquid mortar which is supplied in pressurized condition from the upper end through a central passage 6 extending through the column.

[0015] Under the influence of the pressure prevailing in the said axial clearance in the lower portion of the hole 2 the column 3 is pushed upwardly like a plunger from the hole 2 acting as a hydraulic cylinder. It will be clear that this plunger action can only take place if there is sufficient resistance against "leaking away" of the liquid mortar from the lower closed end of the "cylinder" (hole) 2 to the annular clearance 7 between the vertical wall of the hole 2 and the circumferential surface of the column 3. With a diameter of the supporting column 3 in the order of magnitude of e.g. 1 meter or more, for practical reasons it will not be possible to drill the hole 2_. with a smaller diameter than in the order of magnitude of 110 cm, which implies that the radial dimension of the annular clearance is in the order of magnitude of 5 cm. With such a clearance the liquid mortar would be pressed upwardly along the supporting column substantially unimpeded and the supporting column would not be lifted. In connection therewith the "cylinder volume" below the lower end surface 5 is virtually lined with a cylindrical bag 8, the lower end wall 8a of which will engage the bottom 4 and the upper end wall 8b of which will engage the lower end surface 5 of the column 3. This bag constitutes a closure between said cylinder volume and the annular clearance 7 and is secured with its upper end wall 8b against the lower end surface 5 of-the column 3, e.g. in the manner as indicated in Figure 3, in which a filling pipe 9 is provided in the central passage 6, the lower end of which extends through a central aperture in the upper end wall 8b of the bag 8 and carries a nut 10 whereby the relative bag end wall is retained through the intermediary of a suitable sealing means. Thereafter a flexible filling hose may be connected to the end of said filling pipe extending from the upper end of the column 3.

[0016] When placing the column 3 in the hole 2 the bag 8 is folded around the lower portion of the column 3, namely with both end walls 8a and 8b engaging each other and with the circumferential wall 8c engaging around the lower portion of the column 3 in the shape of an upwardly directed axial fold. By means of an elastic cord or similar means to be provided around the lower portion of the column the bag may then be kept in this folded condition. The said axial bag fold 8c thereby is entered into the annular clearance 7.

[0017] If now through the passage 6 or the filling pipe 9 provided therein respectively, liquid mortar is supplied under pressure to the space below the column, which is closed by the bag, the column 3 is pushed upwardly under the influence of the pressure exerted on its lower end face 5. Therewith the axial fold 8c gradually unrolls along the circumferential wall of the hole 2.

[0018] As the material for the bag 8 a so called "technical fabric" is used of the type which is already applied for many hydraulic engineering purposes and which has the required strength for the present aim. With the 'dimensions, in the present case, of the annular clearance 7 (above a value of 5 cm was mentioned therefore) the pinch tensions occurring in the bag wall 8c (the so called boiler tension) remain below the permissable limit prevailing for this type of material. Preferably a fabric is used which is permeable for water which offers the possibility to use a mortar having a high water percentage, whereby this mortar may be easily pumped. This water is then under the influence of the filling pressure for the larger part pressed through the bag wall outwardly and may escape upwardly through the annular clearance 7. The so called water-cement factor then automatically ariivesat a lower value which furtheres the quality of the final hardened filling body.

[0019] As soon as the column 3 has arrived at the desired height the supply of filling mortar is closed and one may leave the system to harden. Thereby the column in principle is no longer r-equired to be temporarily supported by cranes or similar apparatus.

[0020] In the embodiment according to Figure 1 the hole 2 is used as the cylinder from which the column 3 is pushed upwardly as a plunger. Therewith the column 3 tends to centralize with respect to the hole 2.

[0021] Figure 2 shows an embodiment in which the column 3 may be lowered into the hole 2 in an arbitrary eccentric position, in which this position is retained also during the carrying out of the method. Therefore in the embodiment according to Figure 2 the cylinder function is constituted by a cylindrical chamber 10 formed in the lower end of the column 3, while the plunger function is carried out by an auxiliary piece 11 extending with its central portion lla into this chamber- This auxiliary piece 11 actually constitutes an adjustable pile foot for the column 3, said pile foot being adapted to rest on the bottom 4 of the hole 2. The bag 8' is received in the effective cylinder volume of the chamber 10 in a similar manner as is described with reference to the embodiment according to Figure 1, under the understanding that the circumferential wall 8c' is now positioned in the shape of a downwardly extending axial fold in the annular clearance 7' between the circumferential wall of the chamber 10 and the circumferential wall of the central pile foot portion 11a.

[0022] When entering the column 3 in the embodiment according to Figure 2 the pile foot 11 will be retained temporarily against the lower end surface 5' of the column 3 through the intermediary of means which are easily breakable under the influence of the later on existing filling pressure. As soon as the column has been lowered in the desired horizontal position to the bottom 4 of the hole 2 the column may be adjusted at the desired height by supplying pressurized liquid mortar through the central passage 6'. Thereby the axial bag wall fold 8c' will gradually unroll along the circumferential wall of the chamber _'10 in similar manner as is described with reference to the embodiment according to Figure 1, while the column moves upwardly under the influence of the pressure exerted thereon.

[0023] After the filling material has hardened in the expanded bag 8 or 8' respectively the annular clearance 7 may be filled up with a suitable material, e.g. likewise a hardenable mortar.

Claims

1. A method for adjusting the height of and securing a pile or column shaped body in a hole provided in the bottom, characterized in that a substantially cylindrical bag of flexible material, closed at both ends, is provided in the hole such that both end walls of the bag engage, mutually spaced at short distance, a lower end surface 6f the body and the hole bottom or the upper surface of a stationary auxiliary piece, placed on the bottom, respectively, the circumferential wall of the bag entering, in the shape of an axially directed fold, the annular clearance between a circumferential wall portion of the body on the one hand and the circumferential wall of the hole or a circumferential wall portion of the auxiliary piece, placed therein respectively, on the other hand, whereafter the bag is filled under pressure with a liquid and hardenable mass.

2. A method according to claim 1, characterized in that as the liquid and hardenable mass a hydraulic mortar is used and that a bag is applied having water permeable walls.

3. A supporting pile of supporting column, particularly made of concrete, characterized by a foot which is movable in axial direction with respect to the pile or column body, said foot being received in the manner of a plunger in a cylinder volume present in the lower end of the pile or column body, in which cylinder volume also a substantially cylindrical bag of flexible material, closed at both ends, is provided, such that both end walls are present between the cylinder bottom and the inwardly facing end face of the plunger, the circumferential wall of the bag being positioned in the shape of an axial fold in the annular clearance between the cylinder wall and the plunger.

4. A supporting pile or supporting column according to claim 3, characterized in that it is provided with an axial passage opening into the cylinder volume and is connected through an aperture in the bottom wall of the bag with the interior of the bag.

5. A supporting pile or supporting column according to claim 4, characterized in that a conduit has been provided in the axial passage, said conduit extending through the hole in the upper bag wall, the bag being sealingly secured around said conduit.

6. A supporting pile or supporting column according to claims 3 to 5, characterize in that the bag is made of water permeable material.

7. A supporting pile or supporting column according to claims 3 to 6, characterized in that the portion of the foot extending beyond the cylinder into the body of the pile or column is enlarged with respect to the plunger portion.

Drawing