Hole wall protector, and anchor construction method using said hole wall protector

Abstract

To provide a hole wall protection tool which allows the reuse of a steel pipe temporarily installed on a hole wall, and an anchor installation method using the hole wall protection tool.SOLUTION: A hole wall protection tool 1 includes a cylindrical net member 2, and a support member 3 which supports an inner peripheral surface 2a of the net member 2 toward an outer diameter direction. The support member 3 is provided so as to be spirally wound along the inner peripheral surface 2a of the net member 2.SELECTED DRAWING: Figure 2

Description

Technical Field

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[0001] The present disclosure relates to a hole wall protector for protecting a hole wall and an anchor construction method using the hole wall protector.

Background Art

[0002] Conventionally, a technique for constructing an anchor by drilling an anchor hole in a ground such as a slope, installing a core rod in the anchor hole, and injecting grout is known. Specifically, for example, as shown in FIGS. 4 and 5(a), a steel pipe 6 is attached to a drill 7, and while excavating the ground G of the slope, the hole wall of the anchor hole 5 is protected by the steel pipe 6, a core rod 41 is installed in the steel pipe 6, and a method of injecting grout 42 is known. Further, Patent Document 1 introduces a hole wall protection pipe for protecting the hole wall of an anchor hole.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, according to the conventional anchor construction method, for each anchor, since the steel pipe is removed after the grout is injected, there is a problem that even if it is a small amount, the grout injection work is involved, which takes time and labor. Further, even after the injection of the grout is completed while being protected by the steel pipe, at the stage where the steel pipe is removed, the grout has not hardened, and there is a possibility that the hole wall may collapse and impurities may adhere to the core rod.

[0005] Therefore, an object of the present disclosure is to provide a hole wall protector that enables injection of grout even after the steel pipe is removed and can continue to protect the hole wall until the grout hardens, and an anchor construction method using the hole wall protector.

Means for Solving the Problems

[0006] To solve the above problems, the hole wall protector of this disclosure has the following features. (1) It comprises a cylindrical mesh member and a support member that supports the inner circumferential surface of the mesh member in the outward diameter direction.

[0007] (2) In the case of (1) above, the support member is wound spirally along the inner circumferential surface of the mesh member.

[0008] (3) In the case of (1) or (2) above, the mesh member and the support member are made up of strip-shaped wires.

[0009] Furthermore, in order to solve the above problems, the anchor construction method of this disclosure has the following features. (4) A method for constructing multiple anchors using the borehole wall protectors and steel pipes described in (1) to (3) above, comprising the steps of: excavating a first anchor hole and installing a steel pipe in the excavated first anchor hole; installing a first borehole wall protector inside the steel pipe; removing the steel pipe from the first anchor hole; excavating a second anchor hole and installing a steel pipe in the excavated second anchor hole; installing a borehole wall protector inside the steel pipe; removing the steel pipe from the second anchor hole; and after pouring grout inside the first borehole wall protector, subsequently pouring grout inside the second borehole wall protector. [Effects of the Invention]

[0010] According to the borehole wall protector and the method of installing anchors using the borehole wall protector described herein, the steel pipe can be replaced with the borehole wall protector, and the removed steel pipe can be reused for excavating the next anchor hole. For this reason, there is an advantage that anchors can be installed by, for example, excavating multiple anchor holes while protecting the borehole wall with the borehole wall protector, and then pouring grout into all the anchor holes at once. In addition, there is no risk of the borehole wall collapsing and impurities adhering to the core rod when the steel pipe is removed. [Brief explanation of the drawing]

[0011] [Figure 1] (a) Front view and (b) Cross-sectional view along line AA illustrate a slope with sprayed concrete frame construction. [Figure 2] (a) a perspective view and (b) an exploded perspective view of a hole wall protector showing one embodiment of the present disclosure. [Figure 3] (a) Enlarged view of the main part B, (b) Schematic diagram of the support member. [Figure 4] This is an explanatory diagram illustrating the method for excavating anchor holes and installing steel pipes. [Figure 5] This diagram illustrates (a) a conventional anchor installation method and (b) the anchor installation method of the present disclosure after the installation of steel pipes. [Figure 6] This is an explanatory diagram showing how to install multiple anchors. [Figure 7] This is a schematic diagram showing an example of how borehole wall protectors are connected. [Modes for carrying out the invention]

[0012] Hereinafter, an embodiment of the hole wall protector of this disclosure, specifically a hole wall protector 1 for protecting the hole wall of an anchor hole 5, will be described based on the drawings. Note that the hole wall protector of this disclosure can also be used for other cylindrical hole walls.

[0013] The sprayed concrete frame construction illustrated in Figure 1(a) is a method of stabilizing a slope by creating a grid-like concrete structure C on the slope and fixing the intersections of the grid to the ground G using anchors 4. As shown in Figure 1(b), the anchor 4 consists of a core rod 41 made of metal and a main body 40 made of concrete, and is embedded in the anchor hole 5, integrated with the hole wall protector 1. The tip of the core rod 41 is covered with a protective cap 8.

[0014] As shown in Figure 2, the hole wall protector 1 of this embodiment comprises a cylindrical mesh member 2 embedded in the anchor hole 5 (see Figure 5) and a support member 3 that supports the inner circumferential surface 2a of the mesh member 2. The mesh member 2 is formed into a cylindrical shape by stitching together both sides of a sheet-shaped wire mesh, and the length of the mesh member 2 can be appropriately changed according to the depth of the anchor hole 5. Furthermore, the diameter of the mesh member 2 is set so that the outer circumferential surface 2b is sized to conform to the inner circumferential surface of the steel pipe 6.

[0015] The support member 3 is wound spirally (coil-shaped) along the inner circumferential surface 2a of the mesh member 2. The support member 3 prevents deformation of the mesh member 2 by supporting the inner circumferential surface 2a of the mesh member 2 in the outward diameter direction. The length of the support member 3 can be set to be approximately the same as the length of the mesh member 2. The support member 3 can also be fixed to the mesh member 2 at predetermined intervals. The materials for the mesh member 2 and the support member 3 can be selected to be metal or the like, and it is preferable that the surface is treated with a rust-preventive coating. Furthermore, by winding the support member 3 spirally, slight expansion and contraction in the longitudinal direction of the support member 3 is possible, allowing for fine adjustment of the overall length of the hole wall protector 1.

[0016] As shown in Figure 3, the wires 21 and 31 constituting the mesh member 2 and the support member 3 are each provided in a strip shape. Here, "strip shape" refers to a shape in which the cross-sectional shape of the wires 21 and 31 is elongated or rectangular and has a front surface and a back surface.

[0017] As shown in Figure 3(a), the mesh member 2 is formed by flattening multiple spirally formed wires 21 by crushing them so that peaks 21a and valleys 21b alternately appear, and then intertwining, for example, the valleys 21b of one wire 21 with the peaks 21a' of another wire 21' to form a mesh. Furthermore, the strip surface of each wire 21 constitutes the inner circumferential surface 2a or the outer circumferential surface 2b of the mesh member 2. Because strip-shaped wires 21 are used, compared to the case where the cross-sectional shape of the wires is a perfect circle, there is less protrusion in the inner diameter direction of the mesh member 2, and a wider internal space can be provided for the mesh member 2. In addition, the contact area between the outer circumferential surface 2b of the mesh member 2 and the hole wall of the anchor hole 5 is increased, so the collapse of the hole wall can be prevented more reliably.

[0018] As shown in FIG. 3(b), the strip surface of the wire member 31 constitutes the inner peripheral surface 3a or the outer peripheral surface 3b of the support member 3. Since the strip-shaped wire member 31 is adopted, compared with the case where the cross-sectional shape of the wire member is a perfect circle, the protrusion in the inner diameter direction of the support member 3 is small, and a wide internal space of the support member 3 can be secured. In addition, the contact area between the outer peripheral surface 3b of the support member 3 and the inner peripheral surface 2a of the net member 2 increases, and the net member 2 can be supported more reliably.

[0019] Subsequently, an anchor construction method using the hole wall protector 1 will be described based on FIGS. 4 to 6 while comparing with the conventional method. Although the ground G actually forms a slope, in FIGS. 4 to 6, for the sake of simplifying the drawing, the ground G of the originally inclined slope is shown horizontally.

[0020] As shown in FIG. 4, when installing the steel pipe 6 into the anchor hole 5, the steel pipe 6 is attached to the drill 7 (FIG. 4(1)), and while excavating the ground G with the drill 7, the steel pipe 6 is buried (FIG. 4(2)). After the excavation of the anchor hole 5 is completed (FIG. 4(3)), the drill 7 is removed leaving the steel pipe 6 (FIG. 4(4)). [[ID=!2]]

[0021] [ Here, in the conventional construction method, as shown in FIG. 5(a), after arranging the core rod 41 in the steel pipe 6 and injecting the grout 42 (FIG. 5(a-1)), the steel pipe 6 is extracted (FIG. 5(a-2)). After the embedding of the anchor 4 is completed (FIG. 5(a-3)), the construction of the next anchor 4 is started (FIG. 4(1)).

[0022] On the other hand, in the construction method of the present disclosure, as shown in FIG. 5(b), after installing the hole wall protector 1 inside the steel pipe 6 (FIG. 5(b-1)), the steel pipe 6 is extracted (FIG. 5(b-2)). Using the extracted steel pipe 6, the construction of the next anchor 4 is started (FIG. 4(1)). Then, the core rod 41 is arranged in the hole wall protector 1, and the grout 42 is injected (FIG. 5(b-3)), and the embedding of the anchor 4 is completed (FIG. 5(a-4)).

[0023] According to the construction method of this disclosure, since the steel pipe 6 is replaced with a borehole protector 1, the anchor hole 5 will not collapse even if the steel pipe 6 is removed before the grout 42 is injected. For this reason, for example, as shown in Figure 6, the first borehole protector 1 is installed inside the steel pipe 6 installed in the first anchor hole 5, the steel pipe 6 is removed from the first anchor hole 5, the second anchor hole 5 is excavated, the second borehole protector 1 is installed inside the steel pipe 6 installed in the second anchor hole 5, and the steel pipe 6 is removed from the second anchor hole 5. This process is repeated to install 1 to n borehole protectors 1 in each of the 1 to n anchor holes 5. After that, a sufficient amount of grout 42 is generated for all 1 to n borehole protectors 1, and the grout 42 is injected sequentially or all at once into the inside of the 1 to n borehole protectors 1.

[0024] This construction method eliminates the need to generate and inject grout each time, thus reducing the effort and consumption of grout 42, and ensuring uniform quality of the grout 42. Furthermore, there is no risk of impurities adhering to the core rod 41 due to the collapse of the borehole wall when the steel pipe 6 is removed. Additionally, since the borehole wall protector 1 remains embedded even after the anchor 4 is installed, the anchor 4 is reinforced, improving its durability. Moreover, because the steel pipe 6 is removed before the grout 42 is injected, the grout 42 does not adhere to the steel pipe 6, making the cleaning process easier. The structure, in which a cylindrical mesh member 2 is supported by a support member 3, has a small number of parts and can be easily manufactured.

[0025] This disclosure is not limited to the embodiments described above, and it is possible to implement the invention by appropriately changing the shape and configuration of each part without departing from the spirit of the invention.

[0026] For example, as shown in Figure 7, it is also possible to provide a connecting portion 11 at the end of the hole wall protector 1. By connecting the hole wall protectors 1 to create a hole wall protector 1 of the desired length, it is possible to reduce the effort required to manufacture hole wall protectors 1 of different lengths for each site, and to reduce the burden of transporting long hole wall protectors 1.

[0027] The connecting portion 11 can be a male connecting portion 11a with the support member 3 protruding from the mesh member 2, or a female connecting portion 11b that pulls the support member 3 into the interior of the mesh member 2. In each hole wall protector 1, the male connecting portion 11a and the female connecting portion 11b can be freely combined. For example, as shown in Figure 7(a), both ends of the hole wall protector 1 can be male connecting portions 11a or female connecting portions 11b, or as shown in Figure 7(b), one end of the hole wall protector 1 can be a male connecting portion 11a and the other end can be a female connecting portion 11b. [Explanation of Symbols]

[0028] 1 Hole wall protector 2 Net members 3. Support member 4 Anchors 5 Anchor holes 6 Steel pipe 7 Drill 8. Protective cap 11 Connecting part 21 Wire rod (mesh material) 31. Wire (support member) 40 Main body 41 Core material 42 Grout G Ground

Claims

1. A hole wall protector for protecting the hole wall of a cylindrical anchor hole formed in a slope, A hole wall protector comprising a cylindrical mesh member and a support member that supports the inner circumferential surface of the mesh member in the outward diameter direction.

2. The hole wall protector according to claim 1, wherein the support member is spirally wound along the inner circumferential surface of the mesh member.

3. The hole wall protector according to claim 1, wherein the mesh member and support member are composed of strip-shaped wires.

4. A method for installing multiple anchors using multiple hole wall protectors according to multiple claims 1 and a steel pipe, The process of excavating a first anchor hole while simultaneously installing a steel pipe in the excavated first anchor hole, The process of installing the first hole wall protector inside the steel pipe, The process of removing the steel pipe from the first anchor hole, The process of excavating a second anchor hole and installing the steel pipe into the excavated second anchor hole, The process of installing a second hole wall protector inside the steel pipe, The process of removing the steel pipe from the second anchor hole, A method characterized by comprising the steps of: pouring grout into the inside of the first hole wall protector, and then subsequently pouring grout into the inside of the second hole wall protector.

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