Surrounding rock geological supporting structure of large-dip-angle coal seam transportation roadway

Abstract

The utility model discloses a large-dip-angle coal seam transportation roadway surrounding rock geological supporting structure which is characterized in that 11 anchor rods with the diameter being 20 * 2500 mm are constructed in each row, the row spacing is 850 * 850 mm, 9 anchor rods are arranged on a semicircular vault part, one anchor rod is arranged on each of the left side and the right side of a straight wall part, the bottommost anchor rods are arranged downwards at the angle of 5-10 degrees with the horizontal line, 5 anchor cables are constructed in each row, the row spacing is 1700 mm, and the anchor rods are arranged in the row. Wherein the number of the semicircular arch crown parts is three, the specification is phi 21.6 * 7300 mm, and the spacing is 1800 mm; the straight wall part comprises a left side and a right side, the distance between the straight wall part and the bottom plate is 600-800 mm, and the specification of the straight wall part is phi 21.6 * 4300 mm. According to the supporting structure, a better supporting effect can be effectively achieved on the roadway surrounding rock failure evolution rule, roadway surrounding rock deformation control is effectively achieved, the section area utilization rate is increased, and the supporting economical efficiency is better.

Description

Technical Field

[0001] The utility model relates to the technical field of steep-angle coal seam tunnel support, in particular to a steep-angle coal seam transport tunnel surrounding rock geological support structure. Background Art

[0002] When mining the middle-group coal, the distance between coal seams is small, and the mining of the upper coal seam has a greater impact on the lower coal seam. When mining the lower coal seam, the roof of the lower coal seam becomes more broken and the strength of the surrounding rock becomes lower due to the damage to the floor plate caused by the mining of the upper coal seam. Even if the mining roadway is arranged in the stress reduction zone, it is easy to have the side leg of the coal pillar break, deformation and damage, bottom drum, and even roadway collapse during support. Especially when the distance between the upper and lower coal layers is close, stress concentration will occur near the bottom of the residual coal pillar in the upper coal seam. When the roadway is excavated in the lower coal seam, it will be affected by the dual influence of the original rock stress and the mining stress above. The stress around the mining roadway increases greatly, which puts higher requirements on the roadway support of the lower coal seam.

[0003] In the past, anchor (cable) net support or U-shaped shed support was used to support the mining tunnels under the goaf of coal seams with large inclination angles and close distances. A lot of support experience has been accumulated in the process of safe production over the years. However, on-site investigations have found that for tunnels supported by U-shaped sheds, on the one hand, the shed support operation is intensive, the tunnel excavation speed is slow, and the problem of tight mining and excavation succession is prone to occur; on the other hand, the shed support is a passive support and cannot effectively play the self-bearing role of the surrounding rock. Under the influence of mining on the working face, the tunnel is severely deformed and often requires tunnel repair operations. The tunnels supported by anchor (cable) lack key auxiliary support components such as steel belts, spherical washers, and wear-reducing gaskets. The support efficiency of anchors and cables has not been fully utilized, which not only causes waste of support materials, but also increases the cost of tunnel support and the labor of workers. Summary of the invention

[0004] The technical problem to be solved by the utility model is to provide a surrounding rock geological support structure of a coal seam transport tunnel with a large dip angle, so as to solve the technical problems existing in the prior art.

[0005] The technical solution adopted by the utility model is: a geological support structure for the surrounding rock of a steeply inclined coal seam transport tunnel, with 11 Ф20×2500mm anchor rods constructed in each row, and a row spacing of 850×850mm, including 9 anchor rods in the semicircular arch part, and 1 anchor rod on each side of the straight wall part. The lowest anchor rod is installed at an angle of 5 to 10° downward from the horizontal line, and 5 anchor cables are constructed in each row with a row spacing of 1700mm, including 3 anchor rods in the semicircular arch part, with a specification of Ф21.6×7300mm and a spacing of 1800mm; and 1 anchor rod on each side of the straight wall part, which is 600 to 800mm away from the bottom plate and has a specification of Ф21.6×4300mm.

[0006] The anchor rods in the middle part of the top plate are equipped with steel belts with specifications of 3600×245×3mm, and the anchor rods on both sides are equipped with steel belts with specifications of length×width×thickness=3000×245×3mm. The pallet is a high-strength disc-shaped pallet with specifications of 150×150×10mm, using 1 MSK2380 resin anchor, and the anchor rod preload force is designed to be 80kN. The anchor cable is equipped with T-shaped steel belts with specifications of length×width×thickness=3700×170×5mm (arranged along the direction of the tunnel). The pallet is a high-strength disc-shaped pallet with specifications of 300×300×20mm, using 1 MSK2350 resin anchor (bottom of the hole) and 2 MSZ2360 resin anchors, with a designed preload force of 200kN, and the anchor net uses a diamond steel plate mesh with specifications of Ф4×2000×1000mm.

[0007] Beneficial effects of the utility model: Compared with the prior art, the support structure of the utility model can effectively support the evolution law of tunnel surrounding rock destruction, effectively cope with tunnel surrounding rock deformation control, improve cross-sectional area utilization, and have better support economy. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 It is a schematic diagram of the support cross-section structure of the transport tunnel;

[0009] Figure 2 It is a schematic diagram of the supporting roof structure of the transport lane;

[0010] Figure 3 It is a schematic diagram of the support structure of the transport tunnel. DETAILED DESCRIPTION

[0011] The present invention will be further described below in conjunction with specific embodiments.

[0012] Example 1: The utility model is aimed at the cross-sectional dimensions of the transport tunnel with a net width of 5.2m and a middle height of 3.2m. Therefore, the tunnel excavation width B = 5.2m, the excavation height H = 3.2m, and according to the geomechanical evaluation of the tunnel surrounding rock of the high-angle coal seam group in the mining area, the roof rock stratum Proctor coefficient f 顶 Take 3.19, ω 帮 =arctan(f 顶 )=1.267=72.59°, and the natural equilibrium arch height b=0.97m is obtained by calculation.

[0013] Exposed length of top plate anchor L 杆1 Take 0.1m; the effective length of the anchor rod L 杆2 Not less than the height b of the natural equilibrium arch, which is 1m; the anchoring length L of the anchor 杆3 Take 1m and calculate the anchor length L 杆 =2.1m.

[0014] Exposed length of the side anchor L 帮1 Take 0.1m; the effective length of the anchor rod L 帮2 Calculated by formula (5-4) is 1.25m; the depth of the anchor bolt into the stable rock layer is L 帮3 Take 1m and calculate the anchor length L 帮 =2.35m.

[0015] In combination with engineering practice experience and to facilitate unified on-site management, the length of the top plate anchor rods and the side anchor rods are determined to be 2.5m.

[0016] Anchor yield strength Q 杆 The rod is 127kN; according to the steel product quality certificate provided by Shougang Shuicheng Iron and Steel (Group) Co., Ltd., the yield strength of the anchor rod currently used is s is 495MPa, and the bolt diameter d is calculated 杆 is 18.07 mm. Based on the existing support materials and construction experience, d 杆 =20mm.

[0017] Anchor yield strength Q 杆 The bolt safety factor K is 127kN. Considering that the thickness of the overburden varies greatly due to the mountainous surface and the stress gradient is large in some parts of the tunnel, the bolt safety factor K is 3. The rock bulk density γ is 25.1kN / m 3 ; Anchor rod effective length L 杆2 Take 1.0m, and through calculation, the anchor spacing a does not exceed 1.30m.

[0018] According to the Technical Specifications for Anchor Bolt Support in Coal Mine Lanes, the borehole diameter, bolt diameter and resin anchor diameter of threaded steel resin anchor bolts should be reasonably matched. The difference between the borehole diameter and the bolt body diameter should be 6mm to 10mm; the difference between the borehole diameter and the resin anchor diameter should be 4mm to 8mm. Anchor body diameter D 锚 If the diameter of the drill hole is 20 mm, the diameter of the drill hole D is 28 mm. According to the product model, the diameter of the resin anchor D 药 Take 23mm.

[0019] According to the Technical Specifications for Anchor Bolt Support in Coal Mine Roadways, the design anchor force is the standard value of the anchor yield force, so the design anchor force Q is 156kN; the bond strength between the resin anchor and the rock formation C0 is 2MPa; the borehole diameter D is 28mm, and the anchor bolt anchor length L is calculated. m Not less than 0.89m.

[0020] The diameter of the anchor hole D = 28mm, the diameter of the anchor body D 锚 =20mm, resin roll diameter D 药 =23mm, anchor length L m=0.89m, and the minimum length of the resin anchor is calculated to be 0.64m.

[0021] Because the surrounding rock is relatively broken, combined with construction experience and product models, one MSK2380 resin anchor was selected. The total length of the resin anchor is 0.80m. The total length of the resin anchor section L is calculated. m '=1.10m.

[0022] The current anchor cable strand diameter d1 = 21.6 mm, the strand tensile strength f a The bonding strength between anchor cable and anchoring agent is 1860MPa. c Take 10N / mm 2 , the anchor cable safety factor K is taken as 3, and the anchor length L of the anchor cable deep into the stable layer is calculated 索3 Not less than 3.01m.

[0023] Length of exposed roof plate of roof anchor cable L 索1 Take 0.3m; the effective length of the anchor cable L 索2 Not less than the thickness of the rock layer where the anchor rod is anchored, which is 2.5m according to the length of the anchor rod; the anchor length L of the anchor cable deep into the stable layer 索3 =3.01m, the anchor cable length L is calculated 索 =5.81m.

[0024] According to the Technical Specifications for Anchor Bolt Support in Coal Mine Lanes, the difference between the borehole diameter and the anchor cable diameter should be 6mm to 10mm, and the difference between the borehole diameter and the resin anchor diameter should be 4mm to 8mm. The anchor cable borehole diameter is 28mm. According to the product model, the resin anchor diameter D 药 Take 23mm.

[0025] According to GBT5224-2014 "Steel Strand for Prestressed Concrete", the 0.2% yield strength of a 21.6mm diameter steel strand is 466kN, so the anchor design force Q is 466kN; the bond strength C0 of the resin anchor and the rock formation is 2MPa; the diameter of the anchor hole D = 28mm, and the anchor length L is calculated m Not less than 2.65m.

[0026] The diameter of the anchor hole D = 28mm, the diameter of the anchor cable D 锚 =21.6mm, resin roll diameter D 药 =23mm, anchor cable anchorage length L m =2.65m, and the minimum length of the resin anchor is calculated to be 1.59m.

[0027] Combined with construction experience and product models, one MSK2350 resin anchor and two MSZ2360 resin anchors were selected. The total length of the resin anchor is 1.7m. The total length of the resin anchor section L is calculated. m '=2.83m.

[0028] like Figure 1-3 As shown in the figure, the surrounding rock geological support structure of the steep-angle coal seam transport tunnel is constructed with 11 Ф20×2500mm anchor rods in each row, with a row spacing of 850×850mm, including 9 anchor rods in the semicircular arch part and 1 anchor rod on each side of the straight wall part. The installation angle of the lowest anchor rod is 5-10° downward from the horizontal line. 5 anchor cables are constructed in each row with a row spacing of 1700mm, including 3 anchor cables in the semicircular arch part, with a specification of Ф21.6×7300mm and a spacing of 1800mm; there is 1 anchor rod on each side of the straight wall part, which is 600-800mm away from the bottom plate and has a specification of Ф21.6×4300mm.

[0029] The anchor rods in the middle part of the top plate are equipped with steel belts with specifications of 3600×245×3mm, and the anchor rods on both sides are equipped with steel belts with specifications of length×width×thickness=3000×245×3mm. The pallet is a high-strength disc-shaped pallet with specifications of 150×150×10mm, using 1 MSK2380 resin anchor, and the anchor rod preload force is designed to be 80kN. The anchor cable is equipped with T-shaped steel belts with specifications of length×width×thickness=3700×170×5mm (arranged along the direction of the tunnel). The pallet is a high-strength disc-shaped pallet with specifications of 300×300×20mm, using 1 MSK2350 resin anchor (bottom of the hole) and 2 MSZ2360 resin anchors, with a designed preload force of 200kN, and the anchor net uses a diamond steel plate mesh with specifications of Ф4×2000×1000mm.

[0030] The above description is only a specific implementation method of the present utility model, but the protection scope of the present utility model is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the present utility model, which should be included in the protection scope of the present utility model. Therefore, the protection scope of the present utility model should be based on the protection scope of the claims.

Claims

1. The surrounding rock geological support structure of the steeply inclined coal seam transport tunnel is characterized by: There are 11 Ф20×2500mm anchor rods in each row with a row spacing of 850×850mm, including 9 anchor rods in the semicircular arch part and 1 anchor rod on each side of the straight wall part. The installation angle of the lowest anchor rod is 5-10° downward from the horizontal line. There are 5 anchor cables in each row with a row spacing of 1700mm, including 3 anchor cables in the semicircular arch part with a specification of Ф21.6×7300mm and a spacing of 1800mm; there is 1 anchor cable on each side of the straight wall part, which is 600-800mm away from the bottom plate and has a specification of Ф21.6×4300mm.

2. The surrounding rock geological support structure of the steeply inclined coal seam transport tunnel according to claim 1 is characterized by: The anchor rods in the middle part of the top plate are equipped with steel strips with specifications of 3600×245×3mm, and the anchor rods on both sides are equipped with steel strips with specifications of length×width×thickness=3000×245×3mm. The pallet is a high-strength disc pallet with specifications of 150×150×10mm, and the pallet uses 1 MSK2380 resin anchor. The anchor cable is equipped with T-shaped steel strips with specifications of length×width×thickness=3700×170×5mm. The pallet is a high-strength disc pallet with specifications of 300×300×20mm, and the high-strength disc pallet uses 1 MSK2350 resin anchor and 2 MSZ2360 resin anchors. The anchor net uses a diamond steel plate mesh with specifications of Ф4×2000×1000mm.

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