Roadway full-section anchor net cable, reinforced concrete and shed coupling support system

Abstract

The invention relates to the technical field of underground engineering support, in particular to a roadway full-section anchor net cable, reinforced concrete and shed coupling support system which comprises a primary support, a middle layer support and a steel support, a spraying layer is sprayed on the inner wall of a roadway, a reinforcing mesh is mounted on the inner side of the spraying layer, a plurality of anchor cables are mounted in the roadway, and a plurality of anchor cables are mounted in the spraying layer. The steel bar row is arranged on the inner side of the steel bar mesh, a thin formwork is arranged on the inner side of the steel bar row, and first concrete is arranged between the thin formwork and the spraying layer; the shed frame is arranged on the inner side of the thin formwork, and second concrete is arranged at the bottom of the roadway. For a roadway under the conditions of high tectonic stress and extremely broken soft rock, partial yielding is achieved through anchor cable supporting, rigid constraint is provided by pouring reinforced concrete to limit large deformation, the metal shed frame provides wall face supporting force for the reinforced concrete structure, and the concrete multi-axis strength is improved; an integral coupling support system is formed, and the optimal working performance of different supports can be effectively exerted.

Description

Technical Field

[0001] The invention relates to the technical field of underground engineering support, in particular to a tunnel full-section anchor net cable, reinforced concrete, and scaffolding coupling support system. Background Art

[0002] Under the conditions of high ground stress, extremely soft rock and strong disturbance, deep tunnels in coal mines show long deformation time, large deformation, and repeated failure of support, which is a difficult point in mining engineering management. At present, the main support methods for coal mine tunnels in my country are anchor rods, anchor cables, grouting, spraying, U-shaped scaffolding, pouring concrete, etc. For high-stress soft rock tunnels, two or three of them are generally used to form a combined support system. According to the characteristics of the support method, anchor rods, anchor cables, grouting, etc. are classified as active support systems, which mainly give play to the self-bearing performance of the surrounding rock; while concrete, U-shaped scaffolding, etc. are classified as passive support systems, which resist ground pressure with their own bearing performance and stiffness. From the perspective of support mechanism, domestic and foreign scholars have reached a high degree of consensus on the requirements for coupling of different supports; for this reason, many different coupling support systems have been designed.

[0003] For example, patent CN114165269A invented a composite support system based on steel-concrete composite bracket and shotcrete, which is characterized in that an anchor mesh layer is arranged on the inner wall of the tunnel, a flexible and retractable layer is arranged on the outer side of the anchor mesh layer, a bracket is erected on the outer side of the flexible and retractable layer, steel meshes are arranged on the inner and outer sides of the bracket, and the bracket and the steel mesh are used as the skeleton to construct the shotcrete body layer.

[0004] Patent CN216767407U designs an integrated coupled support device for tunnel surrounding rock, including a primary spraying support grid, a support grid frame, a support connecting layer, anchor cables, and grouting anchor rods.

[0005] Patent CN111828066A proposes an anchor net cable-steel bracket coupling support structure, including a U-shaped steel frame, an anchor net cable mechanism and an anchor net driving mechanism, and system coupling is achieved by connecting two adjacent U-shaped steel frames with an anchor net cable mechanism.

[0006] Patent CN110344841A also proposes an anchor-net-cable steel bracket coupling support structure, including a steel bracket, an arc groove, a threaded hole, a metal mesh, a fixing bolt, a pressure plate, a clamping strip, a pad, a nut, an anchor rod, an anchor cable, a fixing drill, a fixing plate, a fixing hole, a screw rod, a winding rod, a rotating block, a mounting plate and a fixing cone. By setting the anchor rod and anchor cable fixing mechanism, the fixing effect of the metal mesh is improved.

[0007] Patent CN110005434A provides a method for controlling large deformation disasters of surrounding rock in soft rock tunnels with constant resistance and large deformation anchor cables. After tunnel excavation, the section is promptly sealed by spraying to reduce the contact time between the surrounding rock and the air. The steel mesh is quickly laid and the constant resistance and large deformation anchor cables are installed. The surrounding rock is reinforced by the high prestress of the anchor cables. Combined with the steel arch support, a "hard and soft" support effect is formed.

[0008] Patent CN105507923A invented a method of anchor mesh spraying + anchor cable coupling support in a large-span chamber. First, the roof and two sides of the large-span chamber are supported with mesh, inner anchor rods, and anchor cables, and a 100mm thick inner concrete layer is sprayed at the same time. Then, the roof and two sides are supported with mesh and outer anchor rods, and a 100mm thick outer concrete layer is sprayed at the same time, and finally the support construction of the chamber is completed. The double-layer anchor mesh spraying + anchor cable coupling support can be cross-operated in space and time.

[0009] The above invention patents have their own advantages for tunnel support under different conditions, but practice shows that the tunnel support system is still repeatedly damaged when used under multiple unfavorable conditions such as complex geological structures in deep coal mines, extremely soft rocks, and water expansion. In particular, some shaft and tunnel projects are located in areas with complex geological structures, where the structural stress is much greater than the deadweight stress of the rock mass, and the strength, stiffness and toughness of the existing support system are difficult to meet the requirements.

[0010] To this end, the present invention proposes a full-section anchor mesh cable + reinforced concrete + scaffolding coupling support system for the tunnel, which aims to solve the long-term stability problem of tunnel support under conditions of high tectonic stress, extremely broken soft rock, and strong disturbance, especially for long-service-period large-section tunnels, intersections, and locations with multiple repairs under the above conditions. Summary of the invention

[0011] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0012] The present invention provides a tunnel full-section anchor mesh cable, reinforced concrete, and scaffolding coupling support system, which includes primary support, intermediate layer support, and steel brackets. The primary support includes a spray layer, which is sprayed on the inner wall of the tunnel, and a steel mesh is installed on the inner side of the spray layer. A plurality of anchor cables are installed inside the tunnel, and the anchor cables sequentially penetrate the spray layer and the steel mesh. A steel pad is fixedly installed at one end of the anchor cable arranged outside the tunnel, and the steel pad is abutted against the steel mesh.

[0013] The intermediate layer support comprises a steel bar row, the steel bar row is arranged on the inner side of the steel mesh, a thin template is arranged on the inner side of the steel bar row, and a first concrete is arranged between the thin template and the sprayed layer;

[0014] The steel support comprises a scaffolding, which is arranged on the inner side of the thin template and cooperates with the tunnel. The bottom of the tunnel is provided with second concrete, and the second concrete covers the bottom of the scaffolding.

[0015] As a preferred technical solution of the present invention, the steel bar row includes an outer row of steel bars and an inner row of steel bars, the outer row of steel bars is fixedly connected to the exposed end of the anchor cable by a steel wire, the inner row of steel bars is fitted with a thin template, and the outer row of steel bars is connected to the inner row of steel bars by stirrups.

[0016] As a preferred technical solution of the present invention, the scaffolding includes four U-shaped steel brackets, the four U-shaped steel brackets are fixedly connected by annular channel steels, and the second concrete covers the U-shaped steel brackets at the bottom of the tunnel.

[0017] As a preferred technical solution of the present invention, two adjacent scaffolds are fixedly connected by longitudinal channel steel.

[0018] As a preferred technical solution of the present invention, the steel mesh is welded with φ6.5mm round steel, the mesh size is 100mm×100mm, the full section is hung, the steel mesh is overlapped and laid, the overlap width is 100mm, and it is connected by 14# steel wire.

[0019] As a preferred technical solution of the present invention, the thin formwork is a lightweight, thin-layer composite wood board or plywood, which serves as a part of the permanent support after pouring concrete.

[0020] As a preferred technical solution of the present invention, the sprayed layer is a closed surrounding rock formed after the concrete with a thickness of 50 to 60 mm is solidified.

[0021] The beneficial effects of the present invention are:

[0022] 1. A tunnel full-section anchor cable, reinforced concrete, and scaffolding coupled support system. For tunnels under high structural stress and extremely broken soft rock conditions, anchor cable support is used to achieve partial pressure relief, poured reinforced concrete provides rigid constraints to limit large deformation, and metal scaffolding provides wall support for reinforced concrete structures to improve the multi-axial strength of concrete; an overall coupled support system is formed to effectively bring into play the best working performance of different supports.

[0023] 2. A tunnel full-section anchor net cable, reinforced concrete, and scaffolding coupled support system connects the surrounding rock, anchor cables, reinforced concrete, and scaffolding, thereby improving the overall stability of the support system and being able to better resist disturbances from adjacent construction projects.

[0024] 3. A tunnel full-section anchor net cable, reinforced concrete, and scaffolding coupled support system is designed and optimized according to the distribution characteristics of the ground stress field, and the scaffolding is further manufactured to make the support structure more evenly stressed and the overall ability to resist ground pressure is improved.

[0025] 4. A tunnel full-section anchor net cable, reinforced concrete, and scaffolding coupling support system directly uses full-section steel brackets as supports for pouring reinforced concrete formwork, eliminating the need to set up full-floor scaffolding for pouring concrete and saving construction time. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0027] Figure 1 It is a schematic diagram of anchor net spraying one-time support of a tunnel full-section anchor net cable, reinforced concrete, and scaffolding coupling support system of the present invention;

[0028] Figure 2 It is a schematic diagram of the connection between the anchor cable and the steel bar row of a tunnel full-section anchor net cable, reinforced concrete, and shed coupling support system of the present invention;

[0029] Figure 3 It is a schematic diagram of a scaffolding and formwork of a tunnel full-section anchor net cable, reinforced concrete, and scaffolding coupling support system of the present invention;

[0030] Figure 4 It is a first concrete schematic diagram of a tunnel full-section anchor net cable, reinforced concrete, and scaffolding coupling support system of the present invention;

[0031] In the figure: 1. sprayed layer; 2. steel mesh; 3. anchor cable; 4. steel pad; 5. outer row of steel bars; 6. inner row of steel bars; 7. stirrups; 8. thin formwork; 9. longitudinal channel steel; 10. first concrete; 11. second concrete; 12. scaffolding; 1201. circumferential channel steel; 1202. U-shaped steel bracket. DETAILED DESCRIPTION

[0032] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0033] Example: Figure 1-4As shown, a tunnel full-section anchor mesh cable, reinforced concrete, scaffolding coupling support system includes primary support, intermediate layer support and steel support, the primary support includes a spray layer 1, the spray layer 1 is sprayed on the inner wall of the tunnel, a steel mesh 2 is installed on the inner side of the spray layer 1, a plurality of anchor cables 3 are installed inside the tunnel, and the anchor cables 3 sequentially penetrate the spray layer 1 and the steel mesh 2, the anchor cables 3 are arranged outside the tunnel, and a steel pad 4 is fixedly installed at one end, and the steel pad 4 is against the steel mesh 2, the steel mesh 2 is welded with φ6.5mm round steel, the mesh is 100mm×100mm, the full section is hung, the steel mesh 2 is overlapped and laid, the overlap width is 100mm, and 14# steel wire is buckled and connected, the spray layer 1 is a closed surrounding rock formed by consolidation of concrete with a thickness of 50-60mm;

[0034] The middle layer support includes a steel bar row, which is arranged on the inner side of the steel mesh 2, and a thin template 8 is arranged on the inner side of the steel bar row. A first concrete 10 is arranged between the thin template 8 and the sprayed layer 1. The thin template 8 is a lightweight, thin composite wood board or plywood, which serves as a part of the permanent support after pouring concrete;

[0035] The steel support includes a scaffold 12, which is arranged on the inner side of the thin template 8, and the scaffold 12 cooperates with the tunnel, and the bottom of the tunnel is provided with a second concrete 11, and the second concrete 11 covers the bottom of the scaffold 12;

[0036] The cross-sectional dimensions of the tunnel adopt a circular or elliptical structure that matches the characteristics of the geostress field, so that the stress distribution of the surrounding rock and the support system is more uniform. To achieve the above goal, the ratio of the tunnel width to the height is equal to or as close as possible to the lateral pressure coefficient, which can be determined in combination with other design requirements of the tunnel. The lateral pressure coefficient is the ratio of the horizontal geostress to the vertical geostress, which is generally obtained by actual measurement.

[0037] Specifically, refer to Figure 2 and Figure 3 The steel bar row includes an outer row of steel bars 5 and an inner row of steel bars 6. The outer row of steel bars 5 is fixedly connected to the exposed end of the anchor cable 3 by a steel wire, the inner row of steel bars 6 is fitted with a thin template 8, and the outer row of steel bars 5 is connected to the inner row of steel bars 6 by stirrups 7.

[0038] Specifically, refer to Figure 3 The scaffolding 12 includes four U-shaped steel brackets 1202, which are fixedly connected by annular channel steels 1201, and the second concrete 11 covers the U-shaped steel brackets 1202 at the bottom of the tunnel, and two adjacent scaffoldings 12 are fixedly connected by longitudinal channel steels 9.

[0039] Working principle:

[0040] 1. Use actual measurements and other methods to obtain the distribution of the geostress field at the implementation site, and optimize the cross-sectional dimensions based on the tunnel usage requirements, so that the ratio of the tunnel width to height is equal to or as close as possible to the lateral pressure coefficient.

[0041] 2. Based on the optimized cross-sectional dimensions, excavate or expand the tunnel cross-section.

[0042] 3. Arrange the anchor wire mesh support on the whole section (including the bottom plate). It is preferred to use resin anchoring material to bond and anchor the anchor wire 3 to the surrounding rock, then put on the steel mesh, cover it with a steel pad, and tension a certain prestress. The steel mesh 2 is laid in overlapped positions, and the overlaps are connected by steel wire winding. The preferred overlap width is 100 mm.

[0043] 4. Carry out the initial spraying of 50-60 mm thick concrete to consolidate into a spraying layer 1 that seals the surrounding rock.

[0044] 5. One to two months after the primary support construction, when the deformation rate of the surrounding rock gradually increases, or when the cracking of the sprayed layer 1 is more serious, reinforced concrete support construction is carried out.

[0045] 6. Tie the outer row of annular steel bars and longitudinal steel bars to form outer row steel bars 5, which are fixed to the ends of the anchor cables 3 or the steel mesh by wrapping steel wire.

[0046] 7. Tie up the inner row of steel bars 6 and connect the outer row of steel bars 5 with radial stirrups 7.

[0047] 8. First erect the U-shaped steel support 1202 at the bottom of the tunnel and pour the bottom concrete first.

[0048] 9. The U-shaped steel brackets (1202) at the side and top are set up to form a scaffolding 12, which is connected by annular channel steels (1201) and longitudinally connected by longitudinal channel steels 9. The channel steel wing plates are cut off at the connection between the scaffolding 12 and the longitudinal channel steels 9.

[0049] 10. Lay a thin template 8 on the back of the metal scaffolding 12.

[0050] 11. Pour two layers of concrete.

[0051] 12. Pour top slab concrete to form full-section support.

[0052] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A tunnel full-section anchor cable, reinforced concrete, and scaffolding coupling support system, including primary support, intermediate layer support, and steel support, characterized in that: The primary support comprises a sprayed layer (1), the sprayed layer (1) is sprayed on the inner wall of the tunnel, a steel mesh (2) is installed on the inner side of the sprayed layer (1), a plurality of anchor cables (3) are installed inside the tunnel, and the anchor cables (3) sequentially penetrate the sprayed layer (1) and the steel mesh (2), and a steel pad (4) is fixedly installed on one end of the anchor cable (3) arranged outside the tunnel, and the steel pad (4) abuts against the steel mesh (2); The intermediate layer support comprises a steel bar row, the steel bar row is arranged on the inner side of the steel mesh (2), a thin template (8) is arranged on the inner side of the steel bar row, and a first concrete (10) is arranged between the thin template (8) and the sprayed layer (1); The steel support comprises a scaffold (12), the scaffold (12) is arranged on the inner side of the thin template (8), and the scaffold (12) cooperates with the tunnel, the bottom of the tunnel is provided with a second concrete (11), and the second concrete (11) covers the bottom of the scaffold (12).

2. A tunnel full-section anchor cable, reinforced concrete, and scaffolding coupling support system according to claim 1, characterized in that: The steel bar row comprises an outer row of steel bars (5) and an inner row of steel bars (6); the outer row of steel bars (5) is fixedly connected to the exposed end of the anchor cable (3) by a steel wire; the inner row of steel bars (6) is fitted to the thin template (8); and the outer row of steel bars (5) is connected to the inner row of steel bars (6) by a stirrup (7).

3. A tunnel full-section anchor cable, reinforced concrete, and scaffolding coupling support system according to claim 1, characterized in that: The scaffold (12) includes four U-shaped steel brackets (1202), the four U-shaped steel brackets (1202) are fixedly connected by annular channel steels (1201), and the second concrete (11) covers the U-shaped steel brackets (1202) at the bottom of the tunnel.

4. A tunnel full-section anchor cable, reinforced concrete, and scaffolding coupling support system according to claim 1, characterized in that: Two adjacent scaffolds (12) are fixedly connected via longitudinal channel steels (9).

5. The tunnel full-section anchor cable, reinforced concrete, and scaffolding coupling support system according to claim 1 is characterized in that: The steel mesh (2) is welded with φ6.5mm round steel, with a mesh size of 100mm×100mm, and is fully meshed. The steel mesh (2) is overlapped and laid, with an overlap width of 100mm, and is connected by 14# steel wire.

6. A tunnel full-section anchor cable, reinforced concrete, and scaffolding coupling support system according to claim 1, characterized in that: The thin formwork (8) is a lightweight, thin-layer composite wood board or plywood, which serves as a part of the permanent support after pouring concrete.

7. A tunnel full-section anchor cable, reinforced concrete, and scaffolding coupling support system according to claim 1, characterized in that: The sprayed layer (1) is a closed surrounding rock formed after the concrete with a thickness of 50 to 60 mm is solidified.

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