BACKGROUND
Field
[0001] The present disclosure relates to a permanent anchor used for suppression of a collapse
of cut slopes in a rock or ground cutting area or suppression of a collapse of excavation
walls during engineering works and more particularly, to a leading end anchor for
permanent anchoring in which anchor wings of the leading end anchor for performing
a permanent anchoring method are configured to be expanded and unfolded by a grout
injection pressure and grout is compactly filled around the leading end anchor and
in an anchor hole due to a continuous discharge of grout after the expansion and unfolding
of the anchor wings, so that the anchorage of the leading end anchor can be further
improved and high-quality reinforcement work can be carried out without a weakness
of a anchoring part caused by cracks.
Description of the Related Art
[0002] In general, permanent anchors have been used in a soil sheating work for suppression
of a collapse of cut slopes in a rock or ground cutting area, stabilization of slopes,
suppression of landslides, suppression of damage to a large-scale structure, such
as a building or dam, caused by underground water, suppression of damage to an underground
structure, and suppression of a collapse of excavation walls during an engineering
work for building a basement of a large-scale building. Further, the permanent anchors
have been installed to suppress movements or twists of a structure during construction
of a building, a large-scale steel tower or a revetment in an earthquake area, and
assist pressing during construction for a reaction of a cantilever and during a submergence
of a caisson for underwater construction.
[0003] According to the permanent anchoring method, typically, an anchor hole 100 is perforated
in a rock or ground likely to collapse with a drilling machine and a grout hose, a
plurality of tension members 110, and a leading end anchor 130 are prepared as one
unit and inserted through the anchor hole 100 as illustrated in FIG. 1. Then, grout
is injected through the grout hose 120 inserted into the anchor hole 100. If the injected
grout is cured with the leading end anchor 130 after a certain period of time, a pressing
means is installed at the other end of the tension members 110 to fasten an anchoring
device 140. Then, the tension members 110 within a steel strand are tensioned using
a separate hydraulic device or the like to stabilize a target structure.
[0004] Such a conventional permanent anchor supports a tensile force from a surface due
to a ground pressure of grout or a ground friction force. In the permanent anchoring
method, an anchor includes an anchor body anchoring part configured to transfer a
tensile force to the ground with the stress required, a free tension part configured
to transfer a tensile force caused by the stress of the anchor body exhibited in an
anchor head part, and the anchor head part configured to apply the stress required
to a structure. Herein, the anchor body anchoring part is determined by a resistance
between the ground and grout and between the grout and tension members.
[0005] Further, recently, there has been suggested a stronger permanent anchor configured
to resist a tensile stress, a shear stress, and a bending moment through pre-anchoring
of an anchor head part before grout is injected and hardened. Such a permanent anchor
with an improved structure is as disclosed in Korean Patent Laid-open Publication
No.
10-2009-0113436.
[0006] Such a conventional permanent anchor provides the stiffness against drawing by a
ground pressure of grout, and a plurality of cracks may be present around an anchor
hole, into which the anchor is inserted, depending on the condition of the ground
such as a weak ground, a slope, a rock, or the like. It is very difficult to check
cracks within the perforated anchor hole from the outside. That is, when a tension
member is inserted into the anchor hole to inject grout, the grout is filled in the
anchor hole by an injection pressure. Therefore, when the grout is injected into the
anchor hole, the grout may leak from the anchor hole through a plurality of cracks
formed within the anchor hole. Thus, a grout filling rate within the anchor hole is
decreased.
[0007] As such, a plurality of cracks within an anchor hole causes a remarkable decrease
in grout filling rate. Thus, the ground cannot be reinforced in a substantial manner.
Further, even if the cracks are formed within a part of the anchor hole, since the
entire area within the anchor hole is one space, pores are generated within the grout
filled in the entire area of the anchor hole. Thus, the ground cannot be reinforced
in a substantial manner.
[0008] Therefore, it is very difficult and takes a considerable time to measure the strength
of the grout filled in the anchor hole, which results in an increase in construction
period together with an increase in extra expense such as construction expense. Further,
if anchor construction such as reinforcement of a weak ground or a slope is carried
out without checking the presence of pores caused by cracks within the grout filed
in the anchor hole, such faulty construction may cause an increase in maintenance
expense and a ground failure which may result in a big accident.
[0009] Further, as for the conventional permanent anchor, there is the inconvenience of
selecting an anchor suitable for each ground condition and a weight is applied intensively
from a leading end anchoring part to be inserted into the anchor hole, which causes
structural instability. Thus, the anchor hole is perforated and the anchoring part
to be inserted into the anchor hole is formed longer. Therefore, it takes a longer
time to perforate the anchor hole deeply and the increase in length of the anchoring
part causes an increase in installation cost.
[0010] Furthermore, as described above, cement milk grouting, resin, and a leading end anchor
are used to anchor an inner inserted body, i.e., a resistance length, of the anchor
within the anchor hole to the ground as a pre-operation for tensioning the permanent
anchor. However, conventional grouting and resin require some curing time. Therefore,
if a ground deformation is in progress or water is present within the anchor hole,
tensioning cannot be performed well. Further, in case of a conventional leading end
anchor, if tensioning is performed right before grout is injected, a leading end anchoring
part to be pressed and anchored has a small resistance stress and thus may escape
from the anchor hole during tensioning. Therefore, it is very difficult to obtain
the tensile stress required.
SUMMARY
[0011] In view of the foregoing problems, an object to be achieved by the present disclosure
is to provide an improved structure of a leading end anchor for permanent anchoring
in which a steel wire fixing part for fixing and coupling tension wires and an anchoring
head part configured to be expanded and unfolded by a grout injection pressure are
included, and the anchoring head part is coupled to a lower end of the steel wire
fixing part and includes a fluid operating by the grout injection pressure and a plurality
of anchor wings configured to be expanded and unfolded by a pressure applied by the
fluid. Thus, if grout is injected in a state where a leading end anchor is inserted
into an anchor hole, the anchor wings are expanded and unfolded and then strongly
stuck into an inner wall of the anchor hole so as to further improve the fixing force.
Further, when the grout is discharged in a state where the anchor wings are anchored,
the grout is discharged and filled around the anchoring head part and in the anchor
hole. Thus, the anchoring force of the anchoring head part is greatly improved, so
that a higher-quality permanent anchoring method can be realized.
[0012] The present disclosure to achieve the above object includes a steel wire fixing part
to which tension members for permanent anchoring are fixed and an anchoring head part
coupled to a lower side of the steel wire fixing part and fixed within an anchor hole,
and the steel wire fixing part and the anchoring head part are anchored to a leading
end within the anchor hole by grout. The anchoring head part includes: a supporting
rod coupled to the steel wire fixing part; a pressurizing tube body fixed to a leading
end of the supporting rod; a fluid to be inserted into the pressurizing tube body
through an open bottom of the pressurizing tube body; and anchor wings radially hinge-coupled
to a lower end of the supporting rod and brought into contact with a lower end of
the fluid. The fluid is slid by a filling pressure of grout injected into the pressurizing
tube body so as to expand and unfold the anchor wings to the outside.
[0013] According to the present disclosure, in case of embedding a leading end anchor into
a perforated anchor hole, if the anchor hole has an insufficient depth, it is possible
to immediately withdraw the leading end anchor without interference between an inner
surface of the anchor hole and the leading end anchor. Thus, after a re-perforation
operation is performed, it is possible to embed the leading end anchor again. Therefore,
it is easy to correct an operation. While anchor wings are expanded and unfolded by
a discharge pressure of grout, the leading end anchor in an embedded state is strongly
stuck into an inner wall of the anchor hole. Therefore, the fixing force of the leading
end anchor and the anchoring force caused by the grout can be greatly improved. Thus,
a permanent anchor can efficiently perform reinforcement around the leading end anchor
and pores or cracks are not generated in the grout at a leading end of the anchor
hole. Therefore, high-quality construction can be carried out.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The above and other aspects, features and other advantages of the present disclosure
will be more clearly understood from the following detailed description taken in conjunction
with the accompanying drawings, in which:
FIG. 1 is an overall schematic diagram of a conventional permanent anchoring method;
FIG. 2 is an overall perspective view of a leading end anchor according to the present
disclosure;
FIG. 3 is an overall front view of the leading end anchor according to the present
disclosure;
FIG. 4 is an exploded cross-sectional view of the leading end anchor according to
the present disclosure;
FIG. 5 is a perspective view of a state where tension members are coupled and fixed
to the leading end anchor according to the present disclosure;
FIG. 6 is a diagram illustrating a state where the leading end anchor according to
the present disclosure together with the tension members are embedded in an anchor
hole;
FIG. 7 is an enlarged view illustrating a process performed by the leading end anchor
according to the present disclosure and also a cross-sectional view of a state where
grout starts to be injected;
FIG. 8 is an enlarged view illustrating a process performed by the leading end anchor
according to the present disclosure and also a cross-sectional view of a state where
anchor wings are expanded by injection of the grout;
FIG. 9 is an enlarged view illustrating a process performed by the leading end anchor
according to the present disclosure and also a cross-sectional view of a state where
the grout is filled in an anchor hole by continuous injection of the grout;
FIG. 10 is a cross-sectional view of a state where the grout is filled in and around
the leading end anchor according to the present disclosure; and
FIG. 11 is an overall diagram of a state where the leading end anchor according to
the present disclosure is configured for used in bedrocks.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0015] Terms and words used in the present specification and claims are not to be construed
as a general or dictionary meaning, but are to be construed to meaning and concepts
meeting the technical ideas of the present disclosure based on a principle that the
inventors can appropriately define the concepts of terms in order to describe their
own inventions in the best mode.
[0016] Hereinafter, the exemplary embodiments of the present disclosure will be described
in detail with reference to the accompanying drawings.
[0017] FIG. 2 is an overall perspective view of a leading end anchor according to the present
disclosure, FIG. 3 is an overall front view of the leading end anchor according to
the present disclosure, and FIG. 4 is an exploded cross-sectional view of the leading
end anchor according to the present disclosure.
[0018] As illustrated in the drawings, the leading end anchor according to the present disclosure
includes a steel wire fixing part 10 configured to fix tension members 110 formed
of cables and an anchoring head part 20 connected and coupled to a lower side of the
steel wire fixing part 10. In a state where the steel wire fixing part 10 and the
anchoring head part 20 together with the tension members 110 are embedded deeply into
an inner leading end of an anchor hole 100, the anchoring head part 20 is anchored
within the anchor hole 100 by cement milk grout injected into the anchor hole 100.
Thus, reinforcement of a slope part can be carried out by tensioning of the tension
members 110.
[0019] Herein, in the steel wire fixing part 10, guiding parts 12 and 12' including fixing
grooves 11 and 11' formed in all directions are formed to be vertically spaced away
from each other, a winding part 13 around which a single tension member 110 can be
wrapped and bent is formed at a bottom surface of the lower guiding part 12', and
a coupling hole 14 penetrating the winding part 13 is formed at a lateral surface
of the winding part 13.
[0020] Further, the anchoring head part 20 includes a supporting rod 30 including a coupling
piece 21 protruded and formed at a leading end, and a bottom-opened pressurizing tube
body 40 fixed and formed on the supporting rod. A separate fluid 50 is inserted in
the pressurizing tube body 40, and a plurality of anchor wings 60 and 60' coupled
to a hinge-coupling part 31 of the supporting rod 30 are provided under the fluid
50.
[0021] Herein, the coupling piece 21 is protruded and formed at the leading end of the supporting
rod 30. Thus, the coupling piece 21 is brought into close contact with the coupling
hole 14 formed in the winding part 13 of the steel wire fixing part 10 so as to connect
and couple the steel wire fixing part 10 and the anchoring head part 20 to each other
with a separate fixing pin 22.
[0022] Further, the hinge-coupling part 31 radially protruded and formed at a lower end
of the supporting rod 30 is hinge-coupled to each of the anchor wings 60 and 60'.
Thus, the anchor wings 60 and 60' can be expanded and unfolded from the supporting
rod 30 to the outside.
[0023] Furthermore, the pressurizing tube body 40 has a bottom-opened inner space. On a
top surface of the pressurizing tube body 40, a pipe connection hole 42 is formed
so as to communicate with the inner space. Thus, the pressurizing tube body 40 can
be coupled to a separate grout injection pipe 41 through the pipe connection hole
42. On one side of the top surface of the pressurizing tube body 40, a circular cutting
board 44 is formed as one body by a vertical cutting groove 43. A discharge groove
part 45 is formed into a recessed groove on a lower side of an inner surface of the
pressurizing tube body 40.
[0024] Also, the fluid 50 is closely inserted into the pressurizing tube body 40 and slides
in an inner space of the fluid 50. The inner space of the pressurizing tube body 40
has a sealed structure after the fluid 50 is inserted. Thus, as the pressure within
the inner space of the pressurizing tube body 40 is increased, the fluid 50 is pushed
out.
[0025] Further, one side of each of the anchor wings 60 and 60' is slantly in contact with
the fluid 50 and the other side of each of the anchor wings 60 and 60' includes a
slope part 61. One or more sharp tip parts 62 and 62' are formed on outer surfaces
of the anchor wings 60 and 60', respectively.
[0026] Accordingly, in a state where the anchoring head part 20 is coupled to the lower
side of the steel wire fixing part 10 by the supporting rod 30, the pressurizing tube
body 40, the fluid 50, and the anchor wings 60 and 60', the tension members 110 are
united and fixed using the steel wire fixing part 10 as illustrated in FIG. 5, and
then embedded into the anchor hole 100.
[0027] In this case, a method of uniting and fixing the tension members 110 with the steel
wire fixing part 10 includes brining the respective tension members 110 into close
contact with the fixing grooves 11 and 11' formed on the guiding parts 12 and 12'
of the steel wire fixing part 10 and strongly pressurizing and fixing them at the
same time using a separate metal band or the like. One of the tension members 110
is united and fixed as being bent in a "U"-shape along the winding part 13 under the
tension member 110. Thus, the tension member 110 wrapping around the winding part
13 further improves the uniting and fixing force between the steel wire fixing part
10 and the tension members 110.
[0028] The leading end anchor in the above-described state is embedded into the anchor hole
100 previously perforated as illustrated in FIG. 6. The anchor hole 100 is perforated
to have an inner diameter greater than an outer diameter of the leading end anchor
including the tension members 110. Thus, the leading end anchor can be freely embedded
without interference therebetween.
[0029] Further, while the leading end anchor is embedded, if the anchor hole 100 has an
insufficient perforation depth, the leading end anchor is withdrawn again and the
anchor hole 100 needs to be re-perforated. As for the conventional leading end anchor,
during the above-described withdrawal process, interference with an inner wall of
the anchor hole 100 severely occurs. Thus, it is very difficult to perform the withdrawal
operation. Further, the conventional leading end anchor has a structure which cannot
be withdrawn. Therefore, re-perforation or correction of the anchor hole 100 performed
in the present disclosure cannot be performed rationally.
[0030] Thus, if the leading end anchor is embedded into an inner leading end of the anchor
hole 100 by perforating the anchor hole 100, embedding and withdrawing the leading
end anchor, and re-perforating the anchor hole 100 according to the present disclosure,
grout is injected into the pressurizing tube body 40 through the grout injection pipe
41 connected to the pressurizing tube body 40 of the anchoring head part 20 as illustrated
in FIG. 7.
[0031] Thus, as the grout is filled in the pressurizing tube body 40, the fluid 50 is pushed
to the outside of the pressurizing tube body 40 by a pressure of the grout. While
the fluid 50 is pushed toward the anchor wings 60 and 60', the anchor wings 60 and
60' slantly interfering with the fluid 50 are expanded and unfolded to the outside
as illustrated in FIG. 8, so that the tip parts 62 and 62' of the anchor wings 60
and 60' penetrate into the anchor hole 100.
[0032] Thus, while the anchor wings 60 and 60' are unfolded by outward rotation, the slope
parts 61 formed on the anchor wings 60 and 60' suppress the rotation as being brought
into contact with the supporting rod 30. At the same time, the discharge groove part
45 formed on the inner surface of the pressurizing tube body 40 communicates with
the inner space of the pressurizing tube body 40 due to discharge of the fluid 50,
so that the grout inside the pressurizing tube body 40 is discharged to the outside
of the pressurizing tube body 40 as illustrated in FIG. 9. The grout discharged as
such is filled around the anchor wings 60 and 60' and filled deep into the leading
end of the anchor hole 100.
[0033] Further, during the above-described process, if the grout is fully filled into the
pressurizing tube body 40 and the inner leading end of the anchor hole 100 including
the anchor wings 60 and 60', a pressure of the corresponding space is increased. Thus,
the increased pressure is applied to the inside of the pressurizing tube body 40.
Therefore, the pressure is also applied to the cutting board 44 of the pressurizing
tube body 40, resulting in a cross-sectional fracture at the cutting groove 43. Thus,
the cutting board 44 is separated or split to the outside of the pressurizing tube
body 40 by a momentary fracture.
[0034] Therefore, after the cutting board 44 is split from the pressurizing tube body 40,
a hole is naturally formed at an upper part of the pressurizing tube body 40 where
the cutting board 44 was located. Thus, the grout inside the pressurizing tube body
40 is discharged toward the steel wire fixing part 10 and filled through the hole.
[0035] Accordingly, if the grout is compactly injected into the anchoring head part 20 and
the grout is completely injected into the steel wire fixing part 10 and then, the
injected grout is fully cured, the steel wire fixing part 10 and the anchoring head
part 20 can be strongly anchored and fixed by the grout within the anchor hole 100
as illustrated in FIG. 10. The anchor wings 60 and 60' of the anchoring head part
20 are fixed by the grout while the anchor wings 60 and 60' penetrate the inner wall
of the anchor hole 100 as being expanded to the outside. Therefore, even if a high
tensile force is applied to the tension members 110, the anchorage stability is excellent
in an anchoring section.
[0036] In the above-described leading end anchor according to the present disclosure, it
is desirable to form a plurality of tip parts 62 and62' on the outer surfaces of the
anchor wings 60 and 60' for soils. Meanwhile, as for bedrocks, toothed parts 63 and
63' are continuously formed on the outer surfaces of the anchor wings 60 and 60' as
illustrated in FIG. 11, so that if the anchor wings 60 and 60' are expanded to the
outside, the toothed parts 63 and 63' strongly interfere in and resist the inner surface
of the anchor hole 100 formed of bedrocks so as to very effectively suppress a re-withdrawal
from the anchoring head part 20.
[0037] Therefore, in case of correcting a perforation depth of the anchor hole 100, the
leading end anchor of the present disclosure can be easily drawn from an embedded
state and then can be embedded again. Further, while the anchor wings 60 and 60' are
expanded and unfolded as being rotated in all directions by a grout injection pressure,
the anchor wings 60 and 60' are fixed as being strongly stuck into the inner leading
end of the anchor hole 100 formed of soils or bedrocks. Thus, the anchoring force
of the leading end anchor can be further improved. The grout is cured while being
compactly filled deep into the anchor hole 100 and around the anchoring head part
20 and in the steel wire fixing part 10. Thus, the anchoring force of the leading
end anchor of the present disclosure can be further improved, and construction such
as slope reinforcement using a permanent anchor can be carried out with a higher quality.
[0038] Since the embodiments described in the present specification and the configurations
shown in the accompanying drawings are only the most preferred embodiments of the
present disclosure but do not represent for the entire technical spirit of the present
disclosure. Thus, it should be understood that various equivalents and modification
examples capable of replacing the embodiments and configurations of the present disclosure
may exist.
1. A structure of a permanent anchor comprising:
a steel wire fixing part 10 to which tension members 110 for permanent anchoring are
fixed; and
an anchoring head part 20 coupled to a lower side of the steel wire fixing part 10
and fixed within an anchor hole,
wherein and the steel wire fixing part 10 and the anchoring head part 20 are anchored
to a leading end within the anchor hole 100 by grout,
in the steel wire fixing part 10, upper and lower guiding parts 12 and 12' including
fixing grooves 11 and 11' radially formed on outer peripheries are formed, a winding
part 13 extended from the fixing grooves 11 and 11' is protruded downwardly from the
lower guiding part 12' in order for the tension members 110 to be inserted and united
through the fixing grooves 11 and 11', a single tension member 110 is united as being
bent via the winding part 13, and a coupling hole 14 is formed at a lower side of
the winding part 13,
the anchoring head part 20 includes a pressurizing tube body 40, a fluid 50, and anchor
wings 60 and 60', and the fluid 50 is slid by a filling pressure of grout injected
into the pressurizing tube body 40 so as to expand and unfold the anchor wings 60
and 60' to the outside,
the steel wire fixing part 10 and the anchoring head part 20 are connected and coupled
by a supporting rod 30 including a coupling piece and a hinge-coupling part,
the supporting rod 30 and the steel wire fixing part 10 are connected by engaging
a fixing pin into a coupling hole for the coupling piece of the supporting rod and
the steel wire fixing part,
the anchor wings are hinge-coupled through the hinge-coupling part of the supporting
rod,
the pressurizing tube body 40 is fixed to the supporting rod and the fluid 50 is located
within the pressurizing tube body and thus slid as being fit in the supporting rod,
a discharge groove part 45 is formed on a lower side of an inner surface of the pressurizing
tube body 40, so that if the fluid 50 is pushed out by grout injected into the pressurizing
tube body 40, the discharge groove part 45 communicates with the inside of the pressurizing
tube body 40 so as to discharge the grout inside the pressurizing tube body 40 to
the outside through the discharge groove part 45,
on a top surface of the pressurizing tube body 40, a pipe connection hole 42 is formed
to be screw-connected to a grout injection pipe 41 and a cutting board 44 is also
formed by a cutting groove 43, and
when a pressure of the grout injected into the pressurizing tube body 40 is increased,
the cutting grove 43 is fractured and the cutting board 44 is split and removed to
the outside of the pressurizing tube body 40.
2. The structure of a permanent anchor according to claim 1, wherein one side of each
of the anchor wings 60 and 60' is slantly in contact with the fluid 50 and the other
side of each of the anchor wings 60 and 60' includes a slope part 61,
the anchor wings 60 and 60' are expanded and unfolded from the supporting rod 30 by
outward rotation according to a movement of the fluid 50,
while the anchor wings 60 and 60' are expanded and unfolded, an angle of expansion
and unfolding is restricted by interference between the slope parts 61a and the supporting
rod 30,
tip parts 62 and 62' configured to penetrate soils of the anchor hole 100 or toothed
parts 63 and 63' configured to be engaged with and fixed to bedrocks of the anchor
hole 100 are protruded and formed on outer surfaces of the anchor wings 60 and 60'.