Prestress anchoring support method for soft rock roadway

Abstract

The invention discloses a prestress anchoring supporting method for a soft rock roadway. The prestress anchoring supporting method comprises the following steps that s1, a temporary supporting frame is built in the roadway; s2, two sides and a top plate of the roadway are drilled, the drilling sequence is gradually from the bottoms of the two sides to the top of the top plate upwards, the inner diameter of each drilled hole is 10-20 cm, and the depth of each drilled hole is 3-5 m; s3, an anchor rod mold is placed in the hole, and meanwhile the hole is filled with a high-strength expansion material; s4, after the high-strength expansion material is solidified, the anchor rod mold is smashed, hole expanding treatment is conducted to form an anchor hole, and an anchor rod is driven into the anchor hole; and s5, an anchor net is laid on the anchor rods, the anchor net is fixed to the inner wall of the roadway through cooperation of trays and nuts and the anchor rods, and slurry is sprayed to the anchor net. According to the method, the characteristic that a high-strength expansion material expands to firmly break the surrounding rock is utilized, the stress in the broken surrounding rock is changed and adjusted, the self-bearing capacity of the surrounding rock is fully mobilized, an effective and coherent integral structure is formed around a roadway, and the phenomena of stress concentration and stress dispersion in the rock can be effectively reduced.

Description

Technical Field

[0001] The invention relates to the technical field of mining engineering support, and in particular to a prestressed anchoring support method for a soft rock tunnel. Background Art

[0002] In recent years, the geological structure environment faced by coal mining has become increasingly complex, and the difficulty of tunnel support has increased significantly, especially in soft and broken surrounding rock tunnels affected by geological structure stress and adjacent engineering disturbances, where severe roof and floor deformation and obvious mine pressure manifestation characteristics often occur. This not only reduces the production efficiency of coal mines, but also greatly increases the support cost, while exacerbating safety hazards and making the working environment more dangerous. The entire industry urgently needs to conduct in-depth research on technological innovation and support design to improve the safety and production efficiency of coal mines.

[0003] Scholars at home and abroad have conducted a lot of research and experiments on the support issues of soft and broken surrounding rock tunnels. When using traditional support methods, there are no hard rock layers within the coal seam occurrence range, and the rock layer itself is difficult to form a bearing structure. The strong expansion and deformation can easily lead to the loss of anchor prestress, and the anchor support is difficult to form a stable and effective bearing structure. Not only does it require repeated repairs, resulting in high support costs, but the support effect is also unsatisfactory.

[0004] In view of this, it is necessary to improve the existing technology. Summary of the invention

[0005] The object of the present invention is to provide a prestressed anchor support method for soft rock tunnels, aiming to solve at least one of the technical problems existing in the above-mentioned prior art. To achieve the above-mentioned object, the technical solution adopted is as follows:

[0006] A prestressed anchoring support method for a soft rock tunnel, the method comprising the following steps:

[0007] s1. Build temporary support frame in the tunnel;

[0008] s2. Drill holes on the sides and roof of the tunnel, with the drilling sequence from the bottom of the sides to the top of the roof. The inner diameter of the drilled holes is 10-20cm, the depth is 3-5m, the hole spacing is 800mm-1200mm, and the hole row spacing is 2500mm-3000mm;

[0009] s3. Place the anchor mold in the hole and fill it with high-strength expansion material. Adjust the position of the anchor mold before the high-strength expansion material solidifies so that the anchor mold is arranged along the axis of the hole;

[0010] s4. After the high-strength expansion material solidifies, the anchor rod mold is broken and the hole is expanded to form an anchor hole, and the anchor rod is driven into the anchor hole, and the anchor rod protrudes forward from the anchor hole;

[0011] s5. Lay the anchor net on the anchor rod, and fix the anchor net on the inner wall of the tunnel through the tray and nut in conjunction with the anchor rod, and spray slurry on the anchor net;

[0012] s6. Refer to steps s2-s5 to anchor and support the tunnel floor.

[0013] Preferably, the outer diameter of the anchor bolt mould is smaller than the inner diameter of the drilled hole.

[0014] Preferably, the outer diameter of the anchor rod is larger than the outer diameter of the anchor rod mould.

[0015] Preferably, the material of the anchor rod mould is PVE.

[0016] Preferably, the slurry sprayed in step s5 is concrete with a strength of C25-C30.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The present invention provides a prestressed anchoring support method for soft rock tunnels, which consists of two parts: high-strength expansion material extrusion reinforcement support and anchor rod fixed support. In the first part, the stress inside the broken surrounding rock is changed and adjusted by utilizing the characteristic of high-strength expansion material to expand and firmly break the surrounding rock, so as to fully mobilize the self-bearing capacity of the surrounding rock and form an effective and coherent overall structure around the tunnel, which can effectively reduce the stress concentration and stress dispersion in the rock, lay a certain foundation for the subsequent anchoring and anchoring of anchor rods, and ensure the safety and efficiency of the entire project. In the second part, anchoring, laying anchor nets, placing tray nuts, and spraying slurry can firmly fix some of the broken surrounding rock that is expanded and squeezed by the high-strength expansion material, wrap the surrounding rock around the tunnel, form a stable arch-type bearing structure in the surrounding rock, and fully mobilize the bearing capacity of the surrounding rock itself. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solution of the present invention, the drawings required for use in the implementation mode will be briefly introduced below. Obviously, the drawings described below are only some implementation modes of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 It is a schematic diagram of the drilling hole of the present invention.

[0021] Figure 2 It is a schematic diagram of filling the drill hole with high-strength expansion material according to the present invention.

[0022] Figure 3 It is a schematic diagram of breaking the anchor rod mold, expanding the hole and driving the anchor rod according to the present invention.

[0023] Figure 4 It is a schematic diagram of laying the anchor net of the present invention.

[0024] Figure 5 It is a schematic diagram of the tunnel support completed by using the method of the present invention.

[0025] In the figure: 1. Drilling equipment; 2. Hole; 3. Anchor rod mold; 4. High-strength expansion material; 5. Injection equipment; 6. Anchoring equipment; 7. Anchor rod; 8. Anchor net; 9. Tray; 10. Nut. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0027] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be internal communication between two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0028] A preferred embodiment of the present invention provides a prestressed anchoring support method for a soft rock tunnel, the method comprising the following steps:

[0029] s1. Build a temporary support frame in the tunnel. Specifically, build a steel frame in the tunnel to provide temporary support for the tunnel to ensure the safety of the personnel performing subsequent anchor support operations.

[0030] s2. Drill holes on the sides and roof of the tunnel.

[0031] like Figure 1 As shown, the drilling equipment 1 is pushed in to drill holes, and the drilling sequence is from the bottom of the two sides gradually upward to the top of the roof. The inner diameter of the drilled hole 2 is 10-20cm, the depth is 3-5m, the hole spacing is 800mm-1200mm, and the hole row spacing is 2500mm-3000mm.

[0032] s3. In each hole 2, firstly, an anchor mold 3 is placed, the material of the anchor mold 3 is PVE, the outer diameter of the anchor mold 3 is smaller than the inner diameter of the hole 2, and the high-strength expansion material 4 is filled at the same time, specifically, as Figure 2 As shown, a well-proportioned high-strength expansion material 4 is introduced into the hole 2 through an injection device 5. Before the high-strength expansion material 4 solidifies, the position of the anchor mold 3 is adjusted so that the anchor mold 3 is arranged along the axis of the hole 2.

[0033] After the high-strength expansion material 4 expands and solidifies, it squeezes the broken surrounding rocks, making the surrounding broken surrounding rocks connected to a certain extent, thereby making the surrounding rocks on the two sides and the top plate of the tunnel a stable overall structure.

[0034] s4. After the high-strength expansion material 4 solidifies, Figure 3 As shown, the anchor rod mold 3 is first broken by the anchoring device 6 with the hole-expanding anchor rod. Since the outer diameter of the hole-expanding anchor rod is larger than the outer diameter of the anchor rod mold 3, the hole-expanding operation can be performed while the anchor rod mold 3 is broken. After the hole-expanding operation is completed, an anchor hole is formed. Then, the anchor rod 7 is driven into the anchor hole by the anchoring device 6, and the anchor rod 7 protrudes forward from the anchor hole. Among them, the outer diameter of the anchor rod 7 is larger than the outer diameter of the anchor rod mold 3.

[0035] s5. Laying anchor net 8 on anchor rod 7, specifically, as Figure 4 As shown, the integrated anchor net 8 is first hung on the protruding anchor rod 7, and then the anchor net 8 is fixed to the inner wall of the tunnel through the tray 9 and the nut 10 in cooperation with the anchor rod 7. Finally, slurry is sprayed on the anchor net 8, and all the trays 9, nuts 10 and anchor nets 8 are wrapped in concrete to form a complete wrapped shape of the tunnel.

[0036] Furthermore, the slurry sprayed in step s5 is concrete with a strength of C25-C30.

[0037] s6. Refer to steps s2-s5 to anchor and support the tunnel floor. Steps s1-s6 complete the support of the tunnel. Figure 5 shown.

[0038] In summary, a prestressed anchoring support method for a soft rock tunnel described in an embodiment of the present invention consists of two parts: high-strength expansive material extrusion reinforcement support and anchor rod fixed support. In the first part, the stress inside the broken surrounding rock is changed and adjusted by utilizing the characteristics of high-strength expansive materials that expand and firmly break the surrounding rock, so as to fully mobilize the self-bearing capacity of the surrounding rock and form an effective and coherent overall structure around the tunnel, which can effectively reduce the stress concentration and stress dispersion in the rock, and lay a certain foundation for the subsequent anchoring and anchoring of anchor rods, thus ensuring the safety and efficiency of the entire project. In the second part, anchoring, laying anchor nets, placing tray nuts, and spraying slurry can firmly fix some of the broken surrounding rocks that are expanded and squeezed by high-strength expansive materials, wrap the surrounding rock around the tunnel, form a stable arch-type bearing structure in the surrounding rock, and fully mobilize the bearing capacity of the surrounding rock itself.

[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A prestressed anchoring support method for soft rock tunnels, characterized in that: The method comprises the following steps: s1. Build temporary support frame in the tunnel; s2. Drill holes on the sides and roof of the tunnel, with the drilling sequence from the bottom of the sides to the top of the roof. The inner diameter of the drilled holes is 10-20cm, the depth is 3-5m, the hole spacing is 800mm-1200mm, and the hole row spacing is 2500mm-3000mm; s3. Place the anchor mold in the hole and fill it with high-strength expansion material. Adjust the position of the anchor mold before the high-strength expansion material solidifies so that the anchor mold is arranged along the axis of the hole; s4. After the high-strength expansion material solidifies, the anchor mold is broken and the hole is expanded to form an anchor hole, and the anchor is driven into the anchor hole, and the anchor protrudes forward from the anchor hole; s5. Lay the anchor net on the anchor rod, and fix the anchor net on the inner wall of the tunnel through the tray and nut in conjunction with the anchor rod, and spray slurry on the anchor net; s6. Refer to steps s2-s5 to anchor and support the tunnel floor.

2. A prestressed anchoring support method for soft rock tunnel according to claim 1, characterized in that: The outer diameter of the anchor bolt mold is smaller than the inner diameter of the drilled hole.

3. A prestressed anchoring support method for soft rock tunnel according to claim 1, characterized in that: The outer diameter of the anchor rod is larger than the outer diameter of the anchor rod mold.

4. A prestressed anchoring support method for soft rock tunnel according to claim 1, characterized in that: The material of the anchor rod mold is PVE.

5. A prestressed anchoring support method for soft rock tunnel according to claim 1, characterized in that: The slurry sprayed in step s5 is concrete with a strength of C25-C30.

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