KR101285031B1 - Steel strand removing type ground anchor - Google Patents

Abstract

PURPOSE: A strand removable ground anchor is provided to completely remove a strand by fundamentally preventing a strand from being twisted and by being stably anchored in the weak ground with an improved friction force with grout. CONSTITUTION: A strand removable ground anchor comprises a plurality of strands (11,12), anchor bodies (21,22), inner lower bodies (31,32), and a protection cap (40). A plurality of strands is inserted into a boring hole in the weak ground in a longitudinal direction, and sheaths (11a,12a) are coated on an outer circumference of the strands. An end of each strand is clamped so that the anchor bodies are selectively separated. The inner lower bodies are connected to the anchor bodies and comprise insertion holes (31a,32a) which the strands penetrate. The protection cap is installed in the end of the strand and protects the end of the strand. The top-end part of each strand is clamped and it is separable from selectively, the anchor body is combined. The inside lower part of the body has insertion holes (31a,32a) which are combined with the anchor body, and in which strand passes. The protective cap is installed at the top-end part of strand and the top-end part of strand is protected.

Description

Strand Removable Ground Anchor {STEEL STRAND REMOVING TYPE GROUND ANCHOR}

The present invention relates to a ground anchor, and more particularly, by stably injecting grout at the tip of the strand, the fixing can be made very robust, the strand when removing the casing pipe inserted during the drilling of the soft ground The present invention relates to a strand-removable ground anchor that can completely remove the strand after grouting by preventing the twist of the source.

In general, the anchor method is for fixing the structure of civil engineering or construction on the ground, and after connecting with a high-strength tensile material such as stranded wire and applying a high tensile force to the stranded wire, the restraint or prestress in the transverse or vertical direction is applied to the structure. It is a method of protecting or stabilizing a structure from excessive stress, deformation, displacement, etc. generated in the ground by adding

The anchor used in such an anchoring method is a nail nailed to the ground as it is, and has the effect of tying the ground and the structure into one aggregate, and is generally composed of steel wire and cement grout. Anchors are widely used for supporting earthwork of temporary earth-walls, permanent anchor earth-walls, transmission tower foundations, reinforcing dams, buoyancy anchors of underground structures, and slope reinforcement.

Anchors are classified into rock anchors and ground anchors according to the type of ground to be settled, and classified into tiebacks and tiedowns according to the direction in which they are installed. It is classified into low-pressure anchor and high-pressure anchor according to the pressure of, and it is classified into tension type and compression type according to the way that the tension force is applied to the grout body of the anchor, and stress concentration type and stress according to the stress distribution method applied to the anchor. It is classified into a dispersion type, and a stress concentration type is a method of concentrating stress on the tip side of the anchor, and a stress distribution type is a method of uniformly distributing stress over the anchoring section of the anchor.

In addition, anchors are classified into removable anchors and permanent anchors according to their service life.

Removable anchors are intended to temporarily support temporary walls or grounds within two years of use, and are configured to remove stranded wires (tensile material) installed in the grounds after construction.

Permanent anchors have a service life of more than two years and are related to the remaining life of the structure and are usually constructed so as not to remove the strands installed in the ground to maintain long term loads of more than two years.

On the other hand, the construction sequence using the ground anchor drills the ground to a predetermined depth while rotating or hitting by using hydraulic pressure or pneumatic pressure while the steel casing pipe or rod is mounted on the air rig. As such, after inserting the strand bundle of the anchor body and the lower body into the inserted casing pipe at the same time as the perforation of the ground, the pull-out step by step while rotating the casing pipe, tied to the strand bundle When the grout is injected through the grout hose, the grout is discharged from the innermost side of the drill hole, which is the tip position of the strand, and is filled from the bottom to the top.

However, if the ground is soft ground, a part of the drilling hole is easily collapsed after the stepped drawing of the casing pipe, and if a part of the drilling hole is collapsed and the anchor body is buried in the soil, the casing pipe and the strand wire bundle are in the middle of the drawing pipe by rotating it. The rear end of the strand bundle may rotate due to friction with the strand, and when the bundle bundle rotates, the rear portion may be twisted with respect to the tip portion of the strand bundle. Therefore, the strands should be removed after the grouting is completed. Despite this, there was a disadvantage that the strand could not be removed.

 In recent years, various attempts have been made to prevent twisting of strands by installing tubes outside the strands between the anchor body and the anchor body, which is the tip of the strand strand.

However, such a prior art is because the tube is provided with a diameter so as to surround the outer surface of the strand bundle bundle is to be provided with a grout hose in the longitudinal direction on the outside of the tube, and also in the state that both ends of the tube is blocked by the strand wire spacer Since the adhesive tape is used to fix the tube, the spacer and the strand, the grout has not been properly injected into the inner space of the tube, and thus the anchor and the inner body of the strand are not firmly fixed.

And, in the prior art, when the grout hose is inserted into the boring hole of the ground while the grout hose is fixed to the outer surface of the tube, which is the tip of the strand, the grout hose may be caught with the inner surface of the boring hole. There was a downside.

KR 10-0605287 B1 (2006.07.20.)

The present invention has been researched and developed in view of the above drawbacks, and by performing the grout injection to the tip of the strand reliably and effectively to increase the frictional force with the grout, so that the settlement can be made very firm in the soft ground Its purpose is to provide a strand removed ground anchor.

In addition, the present invention can prevent the twisting of the twisted wire in the source when drawing the casing pipe, and the straight line of the strands are secured to remove the stranded wire to be completely removed when you want to remove the strand after completion of grouting The purpose is to provide a type ground anchor.

The strand removal type ground anchor according to the present invention for achieving the above object is a plurality of strands constructed in a drilled hole of a soft ground, with an anchor body coupled to each tip of the strands, one or two anchor bodies together In a ground anchor having a load bearing body mounted thereon,

The strand includes a first strand and a second strand in which the tip portions are spaced at regular intervals and two pairs are formed, and the anchor body is a tip portion of the first anchor body and the second strand strand coupled to the tip portion of the first strand line. It is configured to include a second anchor body coupled to,

A protective cap is installed between the first anchor body and the second anchor body, and the protective cap has a cylindrical structure having a main surface side wall to open the front end and the rear end thereof, and a plurality of grout discharge holes are formed on the main surface side wall. It is

The protective cap is characterized in that the grout hose extending from the rear end of the strand is drawn through the inner space and the grout hose extends to the first anchor portion.

The grout hose is characterized in that the inlet is formed with at least one side injection hole formed in the inner space of the protective cap.

The front end and the rear end of the protective cap is provided with a twist prevention device, respectively, the twist prevention device is formed by the body and one side of the body is a narrow fitting fitting chin narrower than the thickness of the body and the outer peripheral surface of the body and the fitting coupling A plurality of insertion grooves are formed long in the longitudinal direction,

The fitting coupling portion of the twist prevention fitting is fitted to the front end and the rear end of the protective cap, the first insertion groove of the arc-shaped cross-section formed in the body of the twist protection and the arc-shaped cross-section formed in the fitting coupling portion of the fraudulent twist prevention equipment It is formed as two insertion grooves, characterized in that the radius of the first insertion groove is formed larger than the radius of the second insertion groove.

The first insertion groove is made of a size corresponding to the radius of the anchor body to be fitted and coupled to the anchor body, the second insertion groove is characterized in that the strand is inserted and coupled to the size corresponding to the outer diameter of the strand. It is done.

According to the present invention, a protective cap is installed between the tip of the strand, in particular, between the first and second anchor bodies, and a plurality of grout injection holes are formed on the outer circumferential surface of the protective cap so that the grout is formed inside and outside the protective cap. By injecting into the space there is an advantage that can be fixed very firmly in the perforation of the soft ground to the tip of the strand.

In addition, the present invention provides a twist prevention device having a plurality of insertion grooves into which the first strand and the second strand are inserted in each of the front end and the rear end of the protective cap, thereby preventing the twisting of the twisted line being twisted when drawing the casing pipe. It can be prevented, and thus the straightness of the strands is secured there is an advantage that can be completely removed when you want to remove the strands after the grouting is completed.

Figure 1 is a side cross-sectional view showing a state in which the strand removal ground anchor according to an embodiment of the present invention is installed in the perforation of the ground.
Fig. 2 is an enlarged view of a portion indicated by an arrow A in Fig. 1 on an enlarged scale.
3 is an exploded perspective view showing the distal end portion of the strand removal ground anchor according to an embodiment of the present invention.
4 is a perspective view illustrating a coupling relationship between a second anchor body and a twist prevention tool of the strand removal ground anchor according to the present invention.
Figure 5 is a perspective view showing a twist prevention tool of the strand removal ground anchor according to the present invention.
FIG. 6 is a cross-sectional view taken along line BB of FIG. 2.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. For reference, the size, line thickness, and the like of the components shown in the drawings referred to in describing the present invention may be somewhat exaggerated for ease of understanding. The terms used in the description of the present invention are defined in consideration of the functions of the present invention, and thus may be changed depending on the user, the intention of the operator, customs, and the like. Therefore, the definition of this term should be based on the contents of this specification as a whole.

1 and 2 are diagrams illustrating a strand removed ground anchor according to an embodiment of the present invention.

As shown in the figure, the strand removal type ground anchor according to the present invention is detachably attached to a plurality of strands 11 and 12 constructed in the drilled hole 1 in the soft ground and the ends of the strands 11 and 12. Anchor body (21, 22) is coupled to, and the lower body (31, 32) is mounted to the anchor body (21, 22) is configured, including the protective cap (40) at the tip of the strands (11, 12) This is installed and configured to protect the tips of the strands 11 and 12.

A plurality of strands (11, 12) is inserted in the longitudinal direction in the boring hole (1) of the ground, sheath 11a, 12a (sheath) of the synthetic resin material on the outer peripheral surface of the strands (11, 12), an enlarged view and FIG. 6) and the front ends of the sheaths 11a and 12a are coupled to the respective anchor bodies 21 and 22. Accordingly, the strands 11 and 12 may not only be protected from moisture or moisture by the sheaths 11a and 12a but also may be easily separated from the ground by not contacting the soil.

Meanwhile, in FIGS. 1 to 4, the strands 11 and 12 in which the sheaths 11a and 12a are covered with the sheaths 11a and 12a are denoted by 11 and 12 for the convenience of description of the drawings. 11a, 12a) Only the strands 11, 12 are easily separated from the sheaths 11a, 12a because they have a sufficient tolerance (0.5-1.5 mm) with a diameter smaller than the inner diameter.

In addition, the strands 11 and 12 are inserted into the drilled hole 1 so that the tip positions thereof have a predetermined interval in the longitudinal direction of each other. For example, as illustrated in FIGS. 1 and 2, the plurality of strands 11 and 12 may include two first strands 11 and two second strands 12, and the tip portions of the first strands 11 may be provided. Is installed in the state inserted into the innermost of the hole (1), the distal end portion of the second strands 12 are constructed to be spaced apart at a predetermined interval (about 2 ~ 2.5m) from the tip of the first strands (11).

Here, the strand is shown as being constructed only by the two types of the first strand 11 and the second strand 12, but the additional strand (not shown) depending on the construction environment (that is, the length of the anchorage) may be further constructed. In this case, the tip positions of the strands adjacent to each other may be constructed to be spaced at a predetermined interval (about 2 ~ 2.5m).

The leading ends of the respective strands 11 and 12 are clamped and selectively detachably coupled to the anchor bodies 21 and 22, and the anchor bodies 21 and 22 are stranded wires 11 and 12 inserted therein. It has a built-in structure with wedges and springs for clamping the tip of the cable) and separating it selectively.

The lower body 31, 32 is a basic configuration that is formed on the outer surface to increase the frictional force with the grout, the insertion hole 31a, the two strands 11, 12 are inserted or inserted in parallel at regular intervals 32a and fitting grooves 31b and 32b are formed, and one or two anchor bodies 21 and 22 are mounted on one side of the insertion holes 31a and 32a through which the strands 11 and 12 pass. That is, the first loading body 31 is coupled with one or two first anchor bodies 21, and the second loading body 32 is coupled with one or two second anchor bodies 22.

As mentioned above, the load-bearing bodies 31 and 32 are assembled and constructed in a state where they are mounted together with the respective anchor bodies 21 and 22, and the first anchor for convenience with reference to FIGS. 1 and 2. Coupled with the sieve 211 is called the first load-bearing body 31, coupled with the second anchor body 22 is called the second load-bearing body (32).

The tip end portion of the first stranded wire 11 is inserted into the insertion hole 31a of the first load bearing body 31 to be clamped to the first anchor body 21, and the insertion hole 32a of the second load bearing body 32 is provided. ) Is inserted into the tip end portion of the second strand (12) and clamped, and the fitting groove (32b) formed on the outside of the second lower body 32 is inserted in contact with the outer peripheral surface of the first strand (11). do.

The tip end portion of the first stranded wire 11 is inserted into the insertion hole 31a of the first load bearing body 31 and the tip end portion of the second stranded wire 12 is inserted into the insertion hole 32a of the second load-bearing body 32. Is inserted and passes, and a part of the first stranded wire 11 is inserted through the fitting groove 32b of the second inner body 32.

On the other hand, when the protective cap 40 is installed adjacent to the distal end of the first strands 11, the casing pipe (not shown) to be inserted at the time of forming the boring hole 1 of the ground is pulled out (pull out) The front end portions of the first strands 11 by the protective cap 40 can be sufficiently protected even if the inside of the drilling hole 1 in the soft ground or the like.

In particular, the protective cap 40 has a cylindrical structure extending in a length corresponding to the separation interval between the first anchor body 21 and the second anchor body 22, the first anchor body 21 and the second anchor body. It is provided in the longitudinal direction between the (22).

3 and 4, the protective cap 40 has a cylindrical structure having a main surface side wall 42 so that the front end and the rear end thereof are open, and the main surface side wall 42 of the protective cap 40 A plurality of grout discharge holes 41 are formed. In addition, the main surface side wall 42 of the protective cap 40 may be composed of a concave-convex portion such as wrinkles or spiral structure. By the main side wall 42 of the concave-convex portion structure, the protective cap 40 can be more firmly fixed at the time of injection of the grout to be described later.

The grout hose 50 extending from the rear ends of the strands 11 and 12 has an inlet 52 which is led from the rear end of the strand to the tip 51 and the inner space of the protective cap 40. The inlet 52 is a portion adjacent to the tip 51 so that the tip 51 of the grout hose 50 is inserted into the rear end of the protective cap 40, and then is removed from the front end of the protective cap 40. It is installed to be drawn into the inner space of the cap 40. The front end 51 of the grout hose 50 is disposed adjacent to the first anchor body 21 and the first lower body 31 as it is drawn out through the front end of the protective cap 40. The rear end of the grout hose 50 is connected to a grout injector.

On the other hand, a tip injection hole 51a is formed in the tip portion 51 of the grout hose 50, and the grout is formed through the tip injection hole 51a of the first anchor body 21 and the first lower body 31. It is injected into the outer space. At least one side injection hole 51b is formed in the inlet 52 of the grout hose 50, and when the grout is injected through the inner space of the protective cap 40 through the side injection hole 51b, the protective cap ( The grout injected into the inner space of the 40 is injected into the outer space of the protective cap 40 through the grout discharge hole 41 of the protective cap 40 so that the grout is injected into the inner space and the outer space of the protective cap 40. May be injected. Accordingly, the present invention, as the grout is injected into the inside and outside of the protective cap 40 by the grout discharge hole 41 of the protective cap 40, the protective cap 40 and the first anchor body adjacent thereto by the firm coupling force of the grout (21), the second anchor body 22, the first lower body 31, the second lower body 32 and the like can be very firmly fixed at the tip of the drilling hole (1) of the soft ground.

In addition, the rear side of the inlet portion of the grout hose 51 may be partially fixed to the main surfaces of the strands 11 and 12 through adhesive tape or the like.

As shown in Figures 2 and 3, the pair of anti-twist 70 is installed on each of the front end and the rear end of the protective cap 40, the protective cap 40 is the first anchor body ( It can be installed very firmly and stably between the 21) and the second anchor body (22).

As illustrated in FIG. 5, each of the anti-twist members 70 has a body 71 and a fitting portion 72 having a narrower jaw than the thickness of the body 71 on one side of the body 71. The front end portion of the protective cap 40 is secured by adhesive tape or the like after the fitting portion 72 of the front side anti-twisting member 70 is fitted, and the rear side anti-twisting portion is fixed to the rear end of the protective cap 40. After the fitting portion 72 of the 70 is fitted, it is fixed by an adhesive tape or the like. When the fitting coupling portion 72 is inserted and coupled to the protective cap 40, the outer surface of the body 71 is the same as the diameter of the outer peripheral surface of the protective cap 40, so that it is straight without a step. In this state, the protective cap 40 and the anti-twist 70 by adhesively fixing the body 71 of the anti-twist 70 to be inserted into the front end and the rear end of the protective cap 40 by using an adhesive tape. Are integrated into one.

A plurality of first insertion grooves 73 are formed in the body 71 of the anti-twist member 70, and a plurality of second insertion grooves 74 are provided in the fitting portion 72 of the first anti-twist member 70. Is formed, and the first insertion groove 73 and the second insertion groove 74 adjacent in the longitudinal direction are positioned on the same axis. The first insertion groove 73 and the second insertion groove 74 is configured of an arc-shaped cross-sectional structure.

In addition, a stepped portion 75 is formed at a portion where the first insertion groove 73 and the second insertion groove 74 meet on the same axis so that the radius of the first insertion groove 73 is the second insertion groove ( It is formed larger than the radius of 74.

The first insertion groove 73 has a size corresponding to the radius of the anchor body (21, 22) so that the anchor body (21, 22) is easy to fit, the second insertion groove (74) is a twisted line (11, 12) is preferably configured in a size corresponding to the outer diameter of the strands (11, 12) to facilitate fitting.

The first strands 11 are symmetrically fitted to some of the second insertion grooves 74 of the second insertion grooves 74 of the front side anti-twist 70, and the rear side anti-twist 70 Some of the first insertion grooves 73 of the first insertion grooves 73 of the second anchor body 22 is fitted separately, the first strands 11 are the first insertion grooves (73) Passed through and fitted to the second insertion groove (74) side.

On the other hand, the length of the second anchor body 22 is formed to be smaller than the length of the first insertion groove 73 of the rear side anti-twisting tool 70, thereby the front end and the rear side twisted corner of the second anchor body 22 A separation space 76 is formed between the stepped portions 75 of the earth 70, and the grout hose 50 passes through the spaced space 76 between the second anchor body 22 and the stepped portion 75. The inlet portion 52 of the grout hose 50 may be inserted into the protective cap 40 while being inserted into the second insertion groove 74 side.

On the other hand, the outer circumferential edge of each fitting portion 72 corresponds to the inner circumferential surface of the protective cap 40, so that the fitting portion 72 of each of the anti-twisting holes 70 is the front end and the rear of the protective cap 40 After fitting to each end, it is fixed by adhesive tape or the like.

Thus, in the present invention, the first strands 11 are inserted in the longitudinal direction in the second insertion grooves 74 of the front and rear twist prevention holes 70 so that the first strands 11 are in the longitudinal direction thereof. The straightness of the second strands 12 can be kept constant, and the second strands 12 are inserted in the longitudinal direction by fitting the second anchor body 22 into the first insertion groove 73 of the anti-twisting tool 70 on the rear side. The progress of can be kept constant.

In particular, while drawing the drilling hole (1) in the soft ground by drawing the rotating casing pipe to be pulled out step by step from the inside of the hole (1) of the soft ground to the free field beyond the anchorage At this time, in the case of soft ground, a case where a part of the perforation hole 1 of the ground collapses frequently occurs.

Thus, even if a part of the drilling hole 1 is collapsed, as the protective cap 40 is installed between the first anchor body 31 and the second anchor body 32, the strands 11 and 12 are twist prevention holes 70 ) And the protective cap 40, the straightness of the longitudinal direction is maintained constant, even though the casing pipe is continuously rotated while drawing a portion of the drilling hole (1) collapsed first stranded wire (11), which is relatively fragile structurally The tip end portion of the protective cover 40 is embedded in the protective cap 40 and the second anchor wire 22 and the first stranded wire 11 in which the tip of the second strand 12 is clamped by the anti-twist 70. It is fixed as if integrated with the rear end of the (40).

Therefore, when the casing pipe is continuously rotated and drawn in a state where a part of the drilling hole 1 is collapsed, there is no fear of twisting of the first strand 11 and the second strand 12.

Draw the casing pipe to the part corresponding to the free field in the same way as above, but draw it out of the packer (not shown) provided in the middle rear position of the strand, then inject grout or air to the packer at a constant pressure to perforate it. When the hole 1 is blocked and grout is pressurized through the grout hose, the grout discharged from the end is first filled in the protective cap 40 and then discharged through the grout injection hole 41 of the protective cap 40. The drilling hole 1 is filled with a constant pressure. Pressurized injection of such grout is carried out over the second to the third while increasing the pressure, the grout is filled in the drilling hole (1).

As the strands of the strands 11 and 12 are prevented as described above, the grout is completed by pressing the grout to the anchorage of the drilled hole 1 at a predetermined pressure, and then the stranded strands 11 and 12 in the drilled hole 1 of the soft ground. ), There is an advantage that can be removed completely without defects.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. .

11, 12: strand 21, 22: anchor body
31, 32: Lower body 40: Protective cap
41: grout injection hole 42: side wall
43: closed end 70: twist lock
71: body 72: fitting portion
73, 74: Insertion groove

Claims (4)

In the ground anchor having a plurality of strands constructed in the drilled hole of the soft ground, an anchor body coupled to each tip of the strands, a load body mounted with one or two anchor bodies,
The strand includes a first strand and a second strand in which the tip portions are spaced at regular intervals and two pairs are formed, and the anchor body is a tip portion of the first anchor body and the second strand strand coupled to the tip portion of the first strand line. It is configured to include a second anchor body coupled to,
A protective cap is installed between the first anchor body and the second anchor body, and the protective cap has a cylindrical structure having a main surface side wall to open the front end and the rear end thereof, and a plurality of grout discharge holes are formed on the main surface side wall. It is
In the protective cap, a grout hose extending from the rear end of the stranded wire is drawn out through the inner space, and the grout hose extends from the end portion to the first anchor body portion.
The front end and the rear end of the protective cap is provided with a twist prevention device, respectively, the twist prevention device is formed by the body and one side of the body is a narrow fitting fitting chin narrower than the thickness of the body and the outer peripheral surface of the body and the fitting coupling A plurality of insertion grooves are formed long in the longitudinal direction,
The fitting coupling portion of the twist prevention fitting is fitted into the front end and the rear end of the protective cap, the first insertion groove of the arc-shaped cross-section formed in the body of the twist prevention tool and the arc-shaped cross-section formed in the fitting engagement portion of the twist prevention tool 2. The anchor wire-removing ground anchor formed of two insertion grooves, wherein the radius of the first insertion groove is greater than the radius of the second insertion groove. The method according to claim 1,
The grout hose is a strand anchor removal type ground anchor, characterized in that the inlet is formed with at least one side injection hole formed in the inner space of the protective cap. delete The method according to claim 1,
The first insertion groove is made of a size corresponding to the radius of the anchor body to be fitted and coupled to the anchor body, the second insertion groove is characterized in that the strand is fitted and coupled to the size corresponding to the outer diameter of the strand. Retractable ground anchor.

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