Anchor construction method

Abstract

To improve a construction efficiency of an anchor.SOLUTION: An anchor construction method includes a drilling step of drilling an anchor hole 3 with a casing pipe 30 having a drilling bit at its tip, an insertion step of inserting an anchor base 12 into the casing pipe 30, an injection step of injecting grout 14 into a gap between the casing pipe 30 and the anchor base 12, and a withdrawing step of withdrawing the casing pipe 30. In the drilling step, drilling water is supplied to the drilling bit through a flow path 42 in a check valve 40 arranged inside the casing pipe 30, and in the injection step, the flow path 42 in the check valve 40 is blocked by a blocking member 50 inserted into the casing pipe 30, and the check valve 40 is pushed out of the casing pipe 30 by the injection of grout 14.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an anchor installation method. [Background technology]

[0002] Patent Document 1 discloses a method of installing an anchor by drilling an anchor hole in the ground with a casing pipe, injecting grout material into the casing pipe while inserting an anchor steel, and then pulling out the casing pipe while injecting the grout material under pressure. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 7-317059 Summary of the Invention [Problem to be solved by the invention]

[0004] In the anchor installation method described in Patent Document 1, when drilling an anchor hole, drilling water is supplied to the bit through a check valve provided at the tip of the casing pipe. The drilling water in the casing pipe is replaced with grout material by injecting the grout material into the casing pipe, but the injected grout material flows out of the casing pipe through the check valve, so it takes time to replace the water with grout material. As a result, there is a risk that the anchor installation period will be extended and that the grout material will mix with the water in the anchor hole, degrading the installation quality of the anchor.

[0005] An object of the present invention is to improve the installation efficiency and installation quality of anchors. [Means for solving the problem]

[0006] The present invention is an anchor installation method, which includes a drilling step of drilling anchor holes with a casing pipe equipped with a drilling bit at its tip, an insertion step of inserting an anchor base into the casing pipe, an injection step of injecting filler material into the gap between the casing pipe and the anchor base, and an extraction step of pulling out the casing pipe, in which in the drilling step, drilling water is supplied to the drilling bit through a flow path in a check valve arranged inside the casing pipe, and in the injection step, the flow path in the check valve is blocked by a blocking member inserted into the casing pipe, and the check valve is pushed out of the casing pipe by the injection of the filler material. Effect of the Invention

[0007] According to the present invention, it is possible to improve the installation efficiency and installation quality of an anchor. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram showing an example of an anchor installed by the anchor installation method according to an embodiment of the present invention. [Diagram 2] FIG. 13 is a diagram for explaining drilling of anchor holes into which anchors are installed. [Diagram 3] 3 is a diagram of the casing pipe as viewed from the direction of arrow A in FIG. 2. [Figure 4] FIG. 4 is a cross-sectional view taken along line BB in FIG. [Diagram 5] 1 is a flowchart showing a procedure for anchor installation work. [Figure 6] FIG. 13 shows a process of removing the central bit. [Figure 7] 11A to 11C are diagrams showing a process of blocking the flow path of the check valve. [Figure 8] 8 is a cross-sectional view showing a cross section taken along line CC in FIG. 7. [Figure 9] 11A to 11C are diagrams showing a process of injecting a filler material into a casing pipe. [Figure 10] FIG. 13 is a diagram showing a state in which a filler material is pressurized and injected into a casing pipe. [Figure 11]11A and 11B are diagrams showing a process of extracting a casing pipe. [Figure 12] 13A and 13B are diagrams illustrating modified examples of the shielding member. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an anchor installation method according to an embodiment of the present invention will be described with reference to the drawings.

[0010] 1 to 11, a description will be given of the equipment used in the anchor installation method according to the embodiment of the present invention and the process of installing an anchor 10 by the anchor installation method. Note that the following description will be given of the case where the anchor 10 is installed under pressurized groundwater in a continuous wall W installed in ground 1 as shown in Fig. 1, and in particular, the case where the anchor is installed in the planned route 2 of a shield machine S.

[0011] As shown in Fig. 1, anchor 10 is installed in a continuous wall W that constitutes a shaft from which a shield machine S starts, and that is installed in the direction of a planned route 2. Although not shown in Fig. 1, a plurality of anchors other than anchor 10 are installed in the continuous wall W.

[0012] Since the anchor 10 is constructed on the planned route 2 of the shield tunneling machine S, as described below, the components that constitute the anchor 10 and the components that are left in the ground 1 when constructing the anchor 10 are formed of materials and with shapes that do not affect excavation by the shield tunneling machine S.

[0013] Next, a method of drilling the anchor hole 3 for installing the anchor 10 under pressurized groundwater will be described with reference to FIG.

[0014] As shown in FIG. 2, the anchor hole 3 is formed by a drilling machine 20 by so-called single-pipe drilling using a casing pipe 30 capable of supplying drilling water to the cutting portion.

[0015] Specifically, the anchor hole 3 is drilled at a preset angle by a casing pipe 30 inserted into a water-stopping unit 21 composed of a lower guide pipe 22 and an upper guide pipe 23 pre-installed at the anchor hole opening 4 of the continuous wall W, a water-stopping box 24 connected to the upper guide pipe 23, and an air packer 25 connected to the water-stopping box 24.

[0016] The casing pipe 30 is composed of a drilling pipe 32 having a drilling bit attached to its tip surface 33, and an extension pipe 31 connected to the drilling pipe 32. By successively adding extension pipes 31 and drilling holes, the depth of the anchor hole 3 becomes a predetermined depth.

[0017] During drilling, drilling water is supplied through the casing pipe 30 toward the tip face 33, and the drilling water supplied to the tip face 33 travels along the outer surface of the casing pipe 30 together with the excavated soil and sand toward the water-stopping unit 21 as shown by the arrow in Figure 2, and is discharged from the supply and discharge port 24a of the water-stopping box 24.

[0018] A check valve 40 is provided inside the casing pipe 30 through which the drilling water flows, in order to prevent groundwater and excavated soil from flowing into the casing pipe 30 under the pressurized groundwater.

[0019] When drilling of the anchor hole 3 is completed using the casing pipe 30 provided with the check valve 40 in this manner, the casing pipe 30 is pulled out from the anchor hole 3 while or after replacing the water in the anchor hole 3 (drilling water including groundwater) with grout (filling material). In other words, it is necessary to remove the check valve 40 from the casing pipe 30 before pulling out the casing pipe 30.

[0020] Here, for example, if the check valve 40 is removed before injecting grout into the casing pipe 30, groundwater and excavated soil will flow into the casing pipe 30, and even if grout is injected, it will be diluted by the groundwater, etc., and as a result, the anchor 10 may not be easily fixed (deterioration in construction quality). Also, even if the check valve 40 is removed by some method after injecting grout into the casing pipe 30, the check valve 40 may be pushed back by groundwater pressure, and the casing pipe 30 may be blocked by the check valve 40. Also, if a special process is provided to remove the check valve 40, the construction time of the anchor 10 may be extended (deterioration in construction efficiency).

[0021] In order to solve such problems that may arise when installing the anchor 10 under pressurized groundwater, in this embodiment, the anchor 10 is installed by an anchor installation method described below, and in order to execute the anchor installation method, the configuration of the casing pipe 30, and in particular the configuration of the drilling pipe 32, is as follows.

[0022] As shown in Figures 3 and 4, the drilling pipe 32 of the casing pipe 30 in this embodiment is provided with a check valve 40 accommodated in an accommodation hole 32b formed in the drilling pipe 32, and a central bit 35 arranged to cross the space in which the check valve 40 is accommodated. Note that Figure 3 is a diagram of the drilling pipe 32 as viewed from the direction of arrow A in Figure 2, and Figure 4 is a cross-sectional view showing a cross section along line BB in Figure 3.

[0023] The check valve 40 is a ball-type check valve that allows the drilling water flowing inside the casing pipe 30 to flow toward the tip face 33 while preventing groundwater and the like in the ground 1 from flowing into the casing pipe 30. It has a cylindrical main body 41 having a flow path 42 formed therein, the flow path 42 having an inlet 43 and an outlet 44, and a spherical valve body 45 that is positioned within the flow path 42 and is biased by a spring 48 so as to block the flow from the outlet 44 to the inlet 43.

[0024] 4, the check valve 40 is accommodated in an accommodating hole 32b that opens on the tip surface 33 side of the hole-drilling pipe 32. The inner diameter of the accommodating hole 32b is larger than the inner diameter of the through hole 32a that passes through the hole-drilling pipe 32 in the axial direction, and a step 32c formed between the through hole 32a and the accommodating hole 32b functions as a positioning part that determines the position of the check valve 40.

[0025] Furthermore, in order to prevent groundwater from flowing in through a gap between the inner circumferential surface of the accommodation hole 32b and the outer circumferential surface of the main body 41 of the check valve 40, a plurality of O-rings are disposed on the outer circumferential surface of the main body 41 as sealing members 46. Note that, although the sealing members 46 are provided in three locations in the example shown in Fig. 4, the sealing members 46 may be provided in four or more locations, or may be provided in two locations.

[0026] As described below, the check valve 40 is left in the ground 1 after the anchor holes 3 are drilled, and therefore the main body 41 is formed from a resin such as plastic that has better machinability than steel. Note that the material of the main body 41 is not limited to resin, and any material may be used as long as it has better machinability than steel and does not affect drilling by the shield machine S.

[0027] Further, a central bit 35 is provided on the tip surface 33 of the drilling pipe 32 as shown in Figs.

[0028] The central bit 35 is a rod-shaped steel member that is arranged to span a pair of groove portions 33a formed on the tip surface 33 of the drilling pipe 32 and is fixed to the drilling pipe 32 at both ends by spot welding.

[0029] In this way, by providing a central bit 35 that protrudes toward the inside of the accommodating hole 32b so as to cross the space within the accommodating hole 32b in which the check valve 40 is accommodated, the check valve 40 is prevented from coming out of the drilling pipe 32 due to the pressure of the drilling water when drilling the anchor hole 3.

[0030] In addition, a drilling bit is formed on the surface of the central bit 35 facing the ground 1. As a result, when drilling the anchor holes 3, the drilling bit formed on the tip surface 33 of the drilling pipe 32 and the central bit 35 function as a hole drilling section, and the anchor holes 3 are efficiently drilled by the hole drilling section.

[0031] In this way, the central bit 35 functions as a drilling section for drilling the anchor hole 3 and also functions as a stopper for the check valve 40 .

[0032] The shape of the central bit 35 is not limited to the straight line shape shown in Fig. 3, and may be, for example, a cross shape, a Y shape, or a V shape, or multiple straight line members arranged in parallel. However, since the central bit 35 functioning as the hole drilling section is made of steel, it is preferable to make its shape as small as possible so as not to affect the hole drilling by the shield tunneling machine S.

[0033] In addition, it is preferable that the outlet 44 of the check valve 40, which supplies drilling water toward the cutting section, be positioned to avoid the position where the central bit 35 is installed, as shown in Figures 3 and 4. For example, by providing two or more outlets 44, it is possible to open the outlet 44 at a position that does not overlap with the central bit 35, regardless of the relative positioning of the central bit 35 and the check valve 40.

[0034] Next, each step of the anchor installation method for installing the anchor 10 will be described with reference to Fig. 5 to Fig. 11. Fig. 5 is a flow chart showing the procedure of the work of installing the anchor 10, and Figs. 6, 7, and 9 to 11 show the state of each step. Also, Fig. 8 shows a shielding member 50, which will be described later.

[0035] First, in step S11, a water stopping unit 21 such as a guide pipe is installed in the anchor hole mouth 4.

[0036] Specifically, a lower guide pipe 22 is inserted and fixed via a filling material such as mortar into an anchor hole opening 4 that has been cored at a predetermined angle into the continuous wall W, and then an upper guide pipe 23, a water stop box 24, and an air packer 25 are connected in sequence.

[0037] When the installation of the water stop unit 21 is completed, the process proceeds to step S12, in which the anchor holes 3 are drilled by the drilling machine 20 using the casing pipe 30 as described above (drilling step).

[0038] When the anchor hole 3 has been drilled to a predetermined depth, the process proceeds to step S13, where the central bit 35 is removed (central bit removal step).

[0039] Specifically, as shown in Figure 6, an inner rod 37 (rod member) is inserted into the casing pipe 30, the inner rod 37 is pushed in a predetermined amount, and a pushing load is applied to the central bit 35 through the check valve 40, thereby removing the central bit 35 from the tip of the drilling pipe 32.

[0040] In addition, the casing pipe 30 is pulled out in advance by a predetermined length in order to secure a space for arranging the removed central bit 35 and the pushed-out check valve 40. In other words, the anchor hole 3 is overdrilled by a predetermined depth in order to secure a space for leaving the central bit 35 and the check valve 40 at the bottom of the hole.

[0041] In step S13, if the check valve 40 is also removed when removing the central bit 35, groundwater will flow into the casing pipe 30, so the check valve 40 is left in the drilling pipe 32; specifically, at least one sealing member 46, preferably two or more sealing members 46, seal the gap between the inner surface of the accommodating hole 32b of the drilling pipe 32 and the outer surface of the main body 41 of the check valve 40.

[0042] Once the central bit 35 is removed while leaving the check valve 40 in the drilling pipe 32, the inner rod 37 is pulled out from the casing pipe 30, and in the subsequent step S14, the shielding member 50 is inserted into the casing pipe 30 (shielding member insertion process).

[0043] The shielding member 50 is a member that is inserted into the casing pipe 30 to prevent the grout 14 from leaking into the ground 1 through the flow path 42 in the check valve 40 when water such as drilling water in the casing pipe 30 is replaced with grout 14 (filler material) such as cement milk.

[0044] The blocking member 50 inserted into the casing pipe 30 is disposed so as to block the flow path 42 in the check valve 40, as shown in FIG.

[0045] The shielding member 50 is a resin foam formed into a substantially disk-like shape from polyethylene resin or the like, and in the example shown in Figs. 7 and 8, the outer edge 51 is in sliding contact with the inner surface of the casing pipe 30 and the inner edge 52 is attached to the tip of the anchor base 12 and is inserted (anchor base insertion process).

[0046] In addition, as shown in FIG. 8, the shielding member 50 has a plurality of slits 53 extending radially inward from the outer edge 51, and the outer edge 51 side of the shielding member 50 is shaped so that it can partially overlap in the circumferential direction.

[0047] In this manner, the shielding member 50 is made of a material that is relatively flexible, and by providing a plurality of slits 53, it is possible for the shielding member 50 to easily conform to the inner peripheral surface of the casing pipe 30.

[0048] When such a shielding member 50 is inserted into the casing pipe 30, the flow path 42 inside the check valve 40 is shielded by the shielding member 50, and as a result, the gap between the anchor base 12 and the casing pipe 30 and the space in which the check valve 40 is housed are separated by the shielding member 50.

[0049] Therefore, even if grout 14 is injected into the gap between the anchor base 12 and the casing pipe 30 as described below, the grout 14 is prevented from leaking out into the ground 1 through the check valve 40.

[0050] The anchor base 12 to which the shielding member 50 is attached is a tensile structure formed by bundling together multiple wires known as tendons, and is a component that is installed in the anchor hole 3 together with grout 14 to become the anchor 10.

[0051] Incidentally, since the anchor base 12 will also be placed on the planned route 2 of the shield tunneling machine S, a carbon fiber cable (CFCC: Carbon Fiber Composite Cable), which has better machinability than steel, is used as the wire material constituting the anchor base 12. Note that the wire material constituting the anchor base 12 is not limited to a carbon fiber cable, and may be any wire material as long as it is made of a material that has better machinability than steel, has a predetermined tensile strength, and does not affect the drilling by the shield tunneling machine S.

[0052] In step S14, the injection hose 13 used to inject the grout 14 is inserted into the casing pipe 30 together with the anchor base 12.

[0053] In step S14, the flow path 42 in the check valve 40 is blocked by the blocking member 50, Once the anchor base 12 and the injection hose 13 have been inserted into the casing pipe 30, the grout 14 is injected in the following step S15 (grout replacement injection step).

[0054] 9, the grout 14 is injected from an opening 13a of the injection hose 13 that opens at the bottom side of the anchor hole 3, and gradually replaces water such as drilling water that filled the gap between the anchor base 12 and the casing pipe 30. Since the flow path 42 in the check valve 40 is shielded by the shielding member 50 as described above, the grout 14 does not flow out into the ground 1 and is efficiently filled in the casing pipe 30.

[0055] When it is confirmed that a sufficient amount of grout 14 has been injected to replace the drilling water and other water in the casing pipe 30, or that the grout 14 has overflowed from the upper end of the casing pipe 30, thereby sufficiently filling the gap between the anchor base 12 and the casing pipe 30, the process proceeds to step S16, where the check valve 40 is removed (check valve removal process).

[0056] In step S16, first, the injection hose 13 is pulled out from the casing pipe 30, and then a known casing packer (not shown) is attached to the end of the anchor base 12 and inserted into the casing pipe 30, and further a blocking pipe member (not shown) is attached to the upper end of the casing pipe 30. The blocking pipe member is provided with an injection port (not shown) through which grout 14 can be injected, and this makes it possible to pressurize and inject grout 14 into the casing pipe 30 from the upper end side (mouth) of the blocked casing pipe 30.

[0057] When the grout 14 is pressurized and injected into the gap between the anchor base 12 and the casing pipe 30 (pressurized injection step), the pressure of the grout 14 acting on the check valve 40 via the shielding member 50 becomes a load that pushes out the check valve 40, as shown in Fig. 10. Even in this case, the flow path 42 in the check valve 40 is shielded by the shielding member 50 as described above, so that the grout 14 does not flow out into the ground 1, and therefore the pressure of the grout 14 is efficiently converted into a load that pushes out the check valve 40.

[0058] The injection process of injecting the grout 14 into the gap between the anchor base 12 and the casing pipe 30 includes a grout replacement injection process, which is performed to replace water such as drilling water with grout 14, and a pressure injection process, which injects the grout 14 under pressure. The pressure injection process is performed following the grout replacement injection process.

[0059] Due to the pressure of the grout 14 injected under pressure in this manner during the pressure injection process, the check valve 40 is pushed out of the casing pipe 30 and removed from the tip of the casing pipe 30, as shown in FIG.

[0060] When it is confirmed that the check valve 40 has been removed from the casing pipe 30 based on a state change such as a temporary drop in the pressure of the grout 14, the casing pipe 30 is pulled out in the following step S17 by a method similar to that of the conventional method (pulling out step). Note that the step of pulling out the casing pipe 30 may be started simultaneously with the check valve removal step in step S16 where the pressurized injection of the grout 14 is started.

[0061] In step S17, similarly to step S16, the grout 14 is pressurized and injected through a blocking pipe member (not shown) while the casing pipe 30 is gradually pulled out from the drilled anchor hole 3 as shown in Fig. 11. When the length of one extension pipe 31 is pulled out, the pressurized injection is stopped once, the blocking pipe member is removed, and the extension pipe 31 is removed.

[0062] After removing the extension pipe 31, the blocking pipe member is attached again and the grout 14 is pressurized and injected, and the casing pipe 30 is gradually pulled out. When the length of one extension pipe 31 has been pulled out, the pressurized injection is stopped again and the blocking pipe member and the extension pipe 31 are removed.

[0063] By repeating this process, the casing pipe 30 is pulled out of the anchor hole 3, and the inside of the anchor hole 3 becomes filled with grout 14. When the blocking pipe member and the extension pipe 31 are removed, the grout 14 injected into the anchor hole 3 is prevented from flowing back through the casing pipe 30 by the casing packer.

[0064] Then, just before the removal of the casing pipe 30 is completed while the grout 14 is being pressurized and injected, with the casing packer inside the casing pipe 30 and the casing pipe 30 inside the air packer 25, a water glass-based suspension type grout material (LW) is injected through the supply and discharge port 24a of the water stop box 24, and the inside of the water stop unit 21 and around the casing packer are filled with the water glass-based suspension type grout material.

[0065] When the water glass-based suspension-type grout material has hardened to a certain extent and backflow of the grout 14 has been prevented, the process proceeds to step S18, where the guide pipes, etc. are removed. Note that since the lower guide pipe 22 is left in the continuous wall W and will be placed on the planned route 2 of the shield tunneling machine S, the lower guide pipe 22 is made of a hard resin such as hard polyvinyl chloride, which has better machinability than steel.

[0066] Then, when the curing period of the grout 14 in step S19 has elapsed and the anchor base 12 has been fixed to the ground 1, in step S20, tension is applied to the anchor base 12 by a jacking device (not shown), and the anchor base 12 is put into a tensioned state, i.e., into a state having anchor force.

[0067] The anchor base 12 in a tensioned state is fixed to the continuous wall W by a known method via a pressure plate or the like (not shown), thereby installing the anchor 10 in the continuous wall W. In this manner, installation of the anchor 10 is completed through the above-mentioned steps.

[0068] According to the above embodiment, the following effects are achieved.

[0069] According to the anchor installation method of this embodiment, the shielding member 50 inserted into the casing pipe 30 prevents the grout 14 (filler) injected into the casing pipe 30 from flowing into the check valve 40, i.e., prevents the grout 14 from flowing out into the ground 1 through the check valve 40. This makes it possible to quickly replace water such as drilling water in the casing pipe 30 with the grout 14, and also makes it possible to easily remove the check valve 40 from the casing pipe 30 by pushing out the check valve 40 by injecting the grout 14.

[0070] In this way, even when the check valve 40 is installed in the casing pipe 30 through which water such as drilling water flows, such as when drilling the anchor hole 3 under pressurized groundwater, the check valve 40 can be easily removed from the casing pipe 30 and the casing pipe 30 can be pulled out from the anchor hole 3, improving the construction efficiency of the anchor 10. Also, it is possible to prevent the grout 14 (filling material) from being diluted by water such as groundwater, thereby preventing a decrease in the construction quality of the anchor.

[0071] In particular, the process required for removing the check valve 40 is combined with the process of inserting the anchor base 12 and the process of injecting the grout 14, and no separate special process is required. Therefore, even when the anchor hole 3 is drilled under pressurized groundwater, the construction efficiency of the anchor 10 can be improved.

[0072] In addition, the following modified examples are also within the scope of the present invention, and it is possible to combine the configuration shown in the modified example with the configuration described in the above embodiment, or to combine the configurations described in the different modified examples below.

[0073] In the above embodiment, the shielding member 50 is attached to the anchor base 12 and inserted into the casing pipe 30. Alternatively, the shielding member 150 may be inserted into the casing pipe 30 by itself, as in the modified example shown in Fig. 12. In other words, the step of inserting the shielding member 150 into the casing pipe 30 and the step of inserting the anchor base 12 into the casing pipe 30 are separate steps, and the anchor base insertion step is performed after the shielding member insertion step.

[0074] 12 has a shielding body 151 having an outer edge 151a that comes into sliding contact with the inner circumferential surface of the casing pipe 30, and a steel weight 152 attached to the shielding body 151, and descends inside the casing pipe 30 by the weight of the weight 152. The shielding body 151 is formed in a substantially disk shape from polyethylene resin or the like, similar to the above-mentioned shielding member 50, and the weight 152 is formed in a cylindrical shape having a hemispherical tip, for example.

[0075] It is also possible to insert the shielding member 150 into the casing pipe 30 from the upper end side (mouth) of the casing pipe 30, and then inject grout 14 from the mouth of the casing pipe 30, thereby moving the shielding member 150 to a position where it shields the flow path 42 in the check valve 40 by the injection pressure of the grout 14. The shielding member 150 may be inserted into the casing pipe 30 by the inner rod 37 that is inserted when the central bit 35 is removed, and the shielding member 150 may be, for example, a spherical member that is pressed into the check valve 40 so as to block the flow path 42 of the check valve 40.

[0076] Furthermore, in the above embodiment, the shielding member 50 is made of a resin foam, but it may be made of any flexible material, such as a rubber material.

[0077] In the above embodiment, the check valve 40 is provided at the tip of the casing pipe 30. The check valve 40 may be provided in the casing pipe 30, which serves as a supply flow path for drilling water, and may be provided at the connection between the drilling pipe 32 and the extension pipe 31, for example.

[0078] In the above embodiment, the central bit 35 functions as a hole drilling section for drilling the anchor hole 3, and also functions as a retaining section for the check valve 40. Alternatively, the central bit 35 may be a retaining member that functions only as a retaining section for the check valve 40, and in this case, in step S13, the retaining member fixed to the hole drilling pipe 32 is removed.

[0079] In addition, in the above embodiment, the anchor 10 is described as being used to prevent deformation of the continuous wall W, which is an earth retaining wall. However, the anchor 10 may also be used to prevent deformation of underground structures under pressurized groundwater, such as tunnels and underground spaces.

[0080] Although the embodiments of the present invention have been described above, the above-mentioned embodiments merely show some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above-mentioned embodiments. [Explanation of symbols]

[0081] 1...ground 3. Anchor hole 10. Anchor 12 Anchor base 13...Injection hose 14 Grout (filler) 20. Drilling machine 21...Water stop unit 30 Casing pipe 31 Extension pipe 32...Drilled pipe (casing pipe) 33...Tip surface 35...Central bit 37....Inner rod (rod component) 40...Check valve 42 Flow path 50,150...Shielding material 51,151a...Outer edge W... Continuous wall S···Shield tunneling machine

Claims

1. 1. An anchor installation method, comprising: a drilling step of drilling anchor holes using a casing pipe having a drilling bit at its tip; an inserting step of inserting an anchor base into the casing pipe; an injection step of injecting a filler into a gap between the casing pipe and the anchor base; A drawing process of drawing the casing pipe, In the drilling step, drilling water is supplied to a drilling bit through a flow path in a check valve arranged inside the casing pipe, In the injection step, the flow path in the check valve is blocked by a blocking member inserted into the casing pipe, and the check valve is pushed out of the casing pipe by injection of the filler. Anchor installation method.

2. The shielding member is provided on the anchor base. The anchor installation method according to claim 1.

3. The shielding member has an outer edge that can slide against the inner circumferential surface of the casing pipe. The anchor installation method according to claim 1.

4. A central bit is provided at the tip of the casing pipe, the central bit protruding toward the inside of the accommodation hole in which the check valve is accommodated and capable of drilling the anchor hole in the drilling step.

4. An anchor installation method according to claim 1 .

5. a center bit removal step, which is performed before the inserting step, of removing the center bit from the casing pipe through the check valve by inserting a rod member into the casing pipe; The anchor installation method according to claim 4.

6. At least one of the anchor base and the check valve is formed of a material having better machinability than steel.

4. An anchor installation method according to claim 1 .

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