Roadway reverse side arch supporting structure and construction method

Abstract

The roadway reverse side arch supporting structure comprises three-centered arch side walls formed by cutting and opening the two side parts of a roadway, the three-centered arch side walls and a top plate are drilled, anchor rods (cables) are arranged for anchoring, a supporting net is hung on the surface, and steel bar joists are arranged to be pre-tightened and fixed to the anchor rods (cables). Three-center arch shed leg shed supports are arranged on the outer sides of the three-center arch side walls on the two sides at intervals, an I-shaped steel shed beam support is arranged on the outer side of a roadway top plate, three-center arch shed legs are connected with the ends of I-shaped steel shed beams, and the I-shaped steel shed beams, the three-center arch shed legs, the top plate and the side parts are tightly and firmly backed through back plates and wooden wedges. By means of the combined technology of three-center arch cutting forming, active anchor cable supporting and metal micro-arch shed erecting, the problem of serious side bulging of the coal seam roadway can be effectively solved to a certain degree, the supporting strength of the side of the coal seam roadway is improved, and the later maintenance cost of the roadway is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of tunnel support, and in particular relates to a tunnel reverse arch support structure and a construction method. Background Art

[0002] For super-high tunnels and tunnels with soft sides, coal mine tunnels generally use anchor rods, anchor cables, metal mesh and other materials to support the two sides of the excavated coal tunnels, and adjust the support effect by adjusting the support density and length of the support materials. As coal mining gradually extends to the depth, the tunnel mine pressure gradually increases, the coal seam tunnel construction and support problems become increasingly prominent, and the tunnel side drum problem becomes more and more serious. Especially in high tunnels formed by thick coal seam excavation, and the coal seam on the side of the tunnel is relatively soft, the contradiction between the drum problem and the failure of anchor support will become more and more acute. Conventional tunnel anchor side support methods and processes can no longer meet the requirements. Therefore, the technology for reinforcing the side of the soft coal seam tunnel needs further exploration. Summary of the invention

[0003] In order to overcome the deficiencies of the prior art, the present invention provides a tunnel reverse arch support structure and a construction method, so as to improve the surrounding rock performance of the coal body strength at the side of the tunnel.

[0004] The present invention solves its technical problems by adopting the following technical solutions: a tunnel anti-side arch support structure, comprising three-center arch side walls formed by cutting open the walls on both sides of the tunnel, the three-center arch side walls and the top plate are drilled and anchor rods (cables) are arranged for anchoring, a support net is hung on the surface and a steel support beam and the anchor rods (cables) are arranged for pre-tightening and fixing, three-center arch shed legs are arranged at intervals on the outer sides of the three-center arch side walls on both sides for shed support, an I-beam shed beam support is arranged on the outer side of the tunnel top plate, the three-center arch shed legs are connected to the end of the I-beam shed beam, the I-beam shed beam, the three-center arch shed legs, the top plate and the side walls are tightly and solidly backed by back plates and wooden wedges.

[0005] Furthermore, the three-center arch shed legs are overlapped with the bottom wrapping and the top overlap length ≥400mm and the tie angle 86°±1°; The I-beam shed beam is connected to the three-center arch shed leg by a cable, and the adjacent three-center arch shed legs and I-beam shed beams are interlocked by a tie rod; The back plate is arranged vertically on the three-center arch shed legs and I-beam shed beams, with a spacing of ≤200mm, and wooden wedges are driven in two directions; The middle part of the three-center arch shed leg is fixed to the side anchor rod (cable) by a large chain or wire rope.

[0006] The present invention also provides a tunnel reverse arch support construction method, comprising the following steps: Step 1: Cut the roof normally to a horizontal level, and use a multi-purpose excavator to position and cut the soft side walls of the tunnel into three-center arch side walls; Step 2: Knock the top plate and the three-center arch side to ensure good forming, and then actively support the top plate and the three-center arch side with hanging nets and anchor cables; Step 3: The side of the tunnel is supported by a three-center arch leg frame, and the top plate is supported by an I-beam beam. Tie rods are used to interlock the I-beam beams and the three-center arch legs. The I-beam beams, three-center arch legs, top plate and side are tightly secured with back plates and wooden wedges.

[0007] Further, in step three, first, the I-beam shed beam is positioned according to the center line, and the column socket is dug to the solid bottom and leveled; Then, the three-center arch legs are overlapped by the method of wrapping up from below, with the overlap length ≥400mm, the tie angle 86°±1°, and the slope angle of the inclined roadway is 1 / 8~1 / 6 of the roadway slope; Finally, the I-beam shed beam and the three-center arch shed leg are fixed by cable clamps, the adjacent three-center arch shed legs and I-beam shed legs are interlocked with tie rods, the back plate spacing is ≤200mm, and wooden wedges are tightened.

[0008] Furthermore, when the number of sheds is ≥30, the three-center arch shed legs of the starting section and the ending section 1 / 3 are fixed to the side anchor rods (cables) by large chains or steel wire ropes.

[0009] Furthermore, the hill-facing angle is measured by a slope gauge and the 1m plumb line method, with the forward / backward deviation of the horizontal tunnel ≤±1°, corresponding to an end error of ≤17mm for the 1m plumb line.

[0010] Furthermore, the tying angle of the three-center arch shed legs is 86°±1°, and the distance from the end of the 1m vertical line to the front face of the three-center arch shed legs is 52~87mm.

[0011] Furthermore, when the gap at the top of the back plate is ≥300mm, double-layer steel mesh spraying is used to seal it.

[0012] Furthermore, the cable clamp is fixed with two bolts, which are 20~50mm away from the upper and lower edges of the shed legs, and the torque is ≥300N·m.

[0013] Compared with the prior art, the tunnel reverse arch support structure and construction method of the present invention have the following beneficial effects: The present invention can effectively solve the serious problem of coal seam tunnel bulging to a certain extent through the combined process of three-center arch cutting and forming, anchor cable active support and metal micro-arch frame, improve the support strength of the coal seam tunnel side, and reduce the cost of later maintenance of the tunnel. Combined with the quantitative control of the mountain angle and the tie angle, the problem of poor support stability of soft and broken roof and inclined tunnel is solved. The present invention can significantly improve the support strength and reduce the risk of collapse, and is suitable for tunnel construction in complex geological conditions in coal mines. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1It is a cross-sectional front view of the reverse side arch support structure of the present invention; Figure 2 It is a schematic diagram of the method for measuring the mountain angle of the present invention.

[0015] In the figure: 1. Three-center arch side support; 2. Anchor rod (cable); 3. Steel support beam; 4. Three-center arch shed leg; 5. I-beam shed beam. DETAILED DESCRIPTION

[0016] In order to better understand the purpose, structure and function of the present invention, a tunnel reverse arch support structure and construction method of the present invention are further described in detail below in conjunction with the accompanying drawings.

[0017] like Figure 1 As shown, a tunnel anti-side arch support structure includes three-center arch side walls 1 formed by cutting open the walls on both sides of the tunnel, holes are drilled in the three-center arch side walls 1 and the tunnel roof and anchor rods (cables) 2 are arranged for anchoring, a support net is hung on the surface and a steel support beam 3 is arranged to pre-tighten and fix the anchor rods (cables) 2, three-center arch shed legs 4 are arranged on the outside of the three-center arch side walls 1 on both sides for shed support, an I-beam shed beam 5 is arranged on the outside of the tunnel roof for support, the three-center arch shed legs 4 are connected to the end of the I-beam shed beam 5, and the I-beam shed beam 5, the three-center arch shed legs 4 and the roof and the side parts are tightly and solidly backed with back plates and wooden wedges.

[0018] A tunnel reverse arch support construction method comprises the following steps: Step 1: Cutting and forming of three-center arch: Use a multi-purpose tunneling machine to cut the roof horizontally, locate and open the soft side, and form a three-center arch section (net width × height = 3800 × 3500mm). The cutting sequence is to cyclically excavate from the left side to the right side at the bottom, with a penetration of ≤800mm / cycle.

[0019] Step 2: Knocking on the top and active support: After cutting, remove the loose gangue on the top, lay a metal mesh (grid size 100×100mm) and install 2 anchor rods (cables) (row spacing 800~1200mm, exposed ≤80mm).

[0020] Step 3: Scaffolding support construction: Position the I-beam shed beam 5 according to the center line, dig the column hole to the solid bottom and level it, and the three-center arch shed legs 4 are overlapped with the bottom (lap length ≥ 400mm), with a tie angle of 86°±1° (the distance between the ends of the 1m vertical line is 52~87mm); The slope angle of the inclined roadway is 1 / 8~1 / 6 of the roadway slope, and the forward / backward deviation of the horizontal roadway is ≤±1° (1m vertical line error ≤17mm); The I-beam shed beam 5 and the three-center arch shed leg 4 are fixed by cable clamps (the two bolts are 20~50mm away from the upper and lower edges, and the torque is ≥300N·m). The adjacent I-beam shed beams 5 and three-center arch shed legs 4 are interlocked with tie rods, the back plate spacing is ≤200mm, and wooden wedges are tightened.

[0021] When the number of sheds is ≥30, the three-center arch shed legs 4 in the starting section and the ending section 1 / 3 are fixed to the side anchor rods (cables) through large chains / wire ropes; the back top and back plate are sealed with double-layer steel mesh spraying (when the gap is ≥300mm) to improve the overall stability.

[0022] The present invention improves the lateral pressure resistance of the tunnel through three-center arch cutting and metal micro-arch scaffolding collaborative support system.

[0023] Establish a quantitative relationship between the hill angle and the roadway slope (Appendix 1), such as Figure 2 As shown in the figure, the slope gauge and the 1m vertical line method are combined to achieve accurate angle measurement.

[0024] Schedule 1 Example 1: Construction of scaffolding in inclined tunnel The roadway slope is 12°, the hill angle is set at 2° according to Appendix 2, and the measured value at the end of the 1m vertical line is 176mm; The leg 4 of the three-center arch shed has an angle of 86°, the column socket is dug 200mm deep, and the column cap without holes is padded; The distance between sheds is 1000mm, the net height after shed erection is 4200mm, the distance between backboards is 150mm, and wooden wedges are driven in both directions; There are 40 sheds, and the middle parts of the legs of the 14 sheds in the starting section and the 14 sheds in the ending section are fixed to the side anchor cables through Φ18mm steel wire ropes.

[0025] Example 2: Horizontal tunnel scaffolding construction The forward inclination angle deviation of the horizontal tunnel is ±1°, and the end error of the 1m vertical line is ≤17mm; The three-center arch shed leg 4 is tied at an angle of 85°, and the column socket is leveled and then sprayed with C20 concrete for reinforcement; A double-layer metal mesh is hung on the top plate crushing section to reduce the row spacing to 800mm.

[0026] It is to be understood that the present invention is described by some embodiments, and it is known to those skilled in the art that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the scope of protection of the present invention.

Claims

1. A tunnel reverse arch support structure, characterized in that: It includes three-center arch side walls formed by cutting open the walls on both sides of the tunnel. Holes are drilled in the three-center arch side walls and the top plate and anchor rods (cables) are set for anchoring. A support net is hung on the surface and steel support beams and anchor rods (cables) are set for pre-tightening and fixing. Three-center arch shed legs are arranged at intervals on the outside of the three-center arch side walls on both sides for shed support. I-beam shed beams are arranged on the outside of the tunnel top plate for support. The three-center arch shed legs are connected to the ends of the I-beam shed beams. The I-beam shed beams, three-center arch shed legs, the top plate and the walls are tightened and solidified with back plates and wooden wedges.

2. The tunnel reverse arch support structure according to claim 1 is characterized in that: The three-center arch shed legs are overlapped at the bottom and top, with an overlap length of ≥400mm and a tie angle of 86°±1°; The I-beam shed beam is connected to the three-center arch shed leg by a cable, and the adjacent three-center arch shed legs and I-beam shed beams are interlocked by a tie rod; The back plate is arranged vertically on the three-center arch shed legs and I-beam shed beams, with a spacing of ≤200mm, and wooden wedges are driven in two directions; The middle part of the three-center arch shed leg is fixed to the side anchor rod (cable) by a large chain or wire rope.

3. A tunnel reverse arch support construction method, characterized in that: The following steps are involved: Step 1: Cut the roof normally to a horizontal level, and use a multi-purpose excavator to position and cut the soft side walls of the tunnel, and cut them into three-center arch side walls; Step 2: Knock the top plate and the side of the three-center arch to ensure that they are well formed, and then actively support the top plate and the side of the three-center arch with hanging nets and anchor cables; Step 3: The side of the tunnel is supported by a three-center arch leg frame, and the top plate is supported by an I-beam beam. Tie rods are used to interlock the I-beam beams and the three-center arch legs. The I-beam beams, three-center arch legs, top plate and side are tightly secured with back plates and wooden wedges.

4. The tunnel reverse arch support construction method according to claim 3 is characterized in that: In step three, first, locate the I-beam shed beam according to the center line, dig the column hole to the solid bottom and level it; Then, the three-center arch legs are overlapped by the method of wrapping up from below, with the overlap length ≥400mm, the tie angle 86°±1°, and the slope angle of the inclined roadway is 1 / 8~1 / 6 of the roadway slope; Finally, the I-beam shed beam and the three-center arch shed leg are fixed by cable clamps, the adjacent three-center arch shed legs and I-beam shed legs are interlocked with tie rods, the back plate spacing is ≤200mm, and wooden wedges are tightened.

5. The tunnel reverse arch support construction method according to claim 4 is characterized in that: When the number of sheds is ≥30, the three-center arch shed legs of the starting section and the ending section 1 / 3 are fixed to the side anchor rods (cables) through large chains or steel wire ropes.

6. The tunnel reverse arch support construction method according to claim 4 is characterized in that: The facing angle is measured by slope gauge and 1m vertical line method. The forward / backward deviation of the horizontal tunnel is ≤±1°, and the corresponding error at the end of the 1m vertical line is ≤17mm.

7. The tunnel reverse arch support construction method according to claim 4 is characterized in that: The tying angle of the three-center arch shed legs is 86°±1°, and the distance from the end of the 1m vertical line to the front of the three-center arch shed legs is 52~87mm.

8. The tunnel reverse arch support construction method according to claim 4 is characterized in that: When the gap at the top of the back plate is ≥300mm, double-layer steel mesh spraying is used to seal it.

9. The tunnel reverse arch support construction method according to claim 4, characterized in that: The cable clamp is fixed with two bolts, 20~50mm away from the upper and lower edges of the shed legs, with a torque ≥300N·m.

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