A method for constructing a roof-cutting and roadway-retaining support system in conjunction with rockfill retaining support.

Abstract

This invention provides a method for constructing a combined roof-cutting and roadway-retaining support system with rockfill retaining support. It involves asymmetric anchor cable support for the solid coal seam, constant-resistance anchor cable support for the roadway roof, and a support structure between the roadway floor and roof. Support brackets are installed on the roof-cutting side of the roadway, and rockfill retaining support is provided on the goaf side. The support brackets are equipped with lateral support devices, which connect with the rockfill retaining support to form lateral constraints. Reinforcing support is installed between the solid coal seam and the rockfill retaining support. This invention pre-reinforces the surrounding rock of the roadway and constructs a rockfill retaining support structure. The lateral support devices between the support brackets and the rockfill retaining support, and the reinforcing support between the solid coal seam and the rockfill retaining support, apply active support force to the rockfill retaining support using the lateral support devices and reinforcing support. This transforms passive load-bearing into active joint defense, significantly improving the overall stability, deformation resistance, and airtightness of the roadway side support under long-term complex loads, and effectively controlling the roadway cross-section.

Description

Technical Field

[0001] This invention relates to the field of roadway support technology, specifically to a construction method for roof cutting and roadway retention support combined with rock retaining support. Background Technology

[0002] The roof-cutting and roadway-retention method in pillarless mining technology involves cutting off the roof of the goaf sidewall through pre-splitting blasting to form a "short-wall beam" structure. This effectively blocks the transmission of stress from the overlying strata of the goaf to the roadway, and is a key technology for improving coal recovery and reducing roadway excavation. However, roadway retention needs to serve two adjacent working faces and experience two intense mining events. The surrounding rock is under complex dynamic and static load superposition for a long time, which can easily lead to large deformation problems such as continuous roof delamination, sidewall convergence, and floor heave. The requirements for the long-term stability of the roadway are extremely stringent.

[0003] The roadway side support is located at the boundary between the roadway and the goaf, directly bearing the impact of collapse and gangue loads. Its poor structural continuity and insufficient overall stiffness make it prone to continuous deformation into the roadway under long-term dynamic-static load coupling, which is difficult to reinforce. This not only leads to roadway support failure and severe convergence but also poses the risk of creating air leakage channels and increasing the risk of spontaneous combustion of residual coal. Therefore, maintaining the stability of the roadway side support under long-term complex loads is a key challenge for the successful application of roadway retention technology. Summary of the Invention

[0004] The technical problem to be solved by this invention is how to improve the stability of roadway side support.

[0005] The present invention solves the above-mentioned technical problems through the following technical means:

[0006] This invention provides a method for constructing a combined roof cutting and roadway retention support system with rockfill retaining support. The system employs asymmetric anchor cable support for the solid coal seam, constant resistance anchor cable support for the roadway roof, support structures between the roadway floor and roof, bracket support for the roof cutting line side, and rockfill retaining support for the goaf. The bracket support is equipped with lateral support devices, which connect with the rockfill retaining support to form lateral constraints. Reinforcing support is installed between the solid coal seam and the rockfill retaining support.

[0007] Beneficial effects: This invention first reinforces the roadway with support, and then applies active support force to the rock retaining support by using the lateral support device between the support frame and the rock retaining support and the reinforcement support between the solid coal side and the rock retaining support. This transforms passive load-bearing into active joint defense, achieving a unified "yield-resistance" effect. It can significantly improve the overall stability, deformation resistance and airtightness of the roadway support under long-term complex loads, effectively control the roadway cross-section and ensure the long-term safe reuse of the roadway.

[0008] Preferably, the asymmetric anchor cable support includes at least two rows, comprising a first row and a second row of anchor cable support. The distance between the first row and the second row of support is 1000mm. The first row of support is constructed by anchoring the anchor cable at a certain angle to the plumb line towards the solid coal face. The second row of support is constructed by anchoring the anchor cable perpendicular to the solid coal face. The horizontal spacing of the anchor cables is 900mm.

[0009] More preferably, the inclination angle is 75 degrees, and the distance between the orifice of the first row of supports and the bottom plate is 1200 mm.

[0010] More preferably, the distance between the opening of the second row of supports and the bottom plate is 2200mm.

[0011] More preferably, the anchor cable is fixed to the solid coal side by an I-beam.

[0012] Preferably, the specific operation of constant resistance anchor cable support is as follows: constant resistance large deformation anchor cables and channel steel are used to support the roadway roof. The constant resistance large deformation anchor cables are equipped with constant resistance devices and locking devices.

[0013] Preferably, the specific operation of the support is as follows: hydraulic units are used to provide vertical support for the roadway between the roof and floor.

[0014] Beneficial effects: This invention controls delamination or uneven deformation of the roadway roof through support and reinforcement.

[0015] Preferably, the specific operation of the support frame is as follows: a stacked support frame is used to support the roof slab on the side of the roadway cut-off line. The stacked support frame is equipped with a transverse support device, which is connected to the rock retaining support.

[0016] Preferably, the lateral support device includes a hydraulic cylinder and a claw. One end of the hydraulic cylinder is fixed to the stack-type support, and the other end is a telescopic end, which is connected to the rock retaining support through the claw.

[0017] Beneficial effects: This invention utilizes the telescopicity of hydraulic cylinders to apply active and adjustable support force to rock retaining supports, thus solving the problem of dynamic balance of lateral pressure.

[0018] More preferably, the stacked support is 500mm away from the top cutting hole, and multiple stacked supports are arranged along the roadway, with the center distance between adjacent stacked supports being 2000mm.

[0019] More preferably, the stacked support has a length of 1500mm, a top beam width of 600mm, and a working height of 2600mm to 4000mm.

[0020] Preferably, the rock retaining support includes a flexible buffer layer and a rigid frame layer, with one side of the flexible buffer layer closely attached to the goaf and the other side fixed by the rigid frame layer.

[0021] Beneficial effects: This invention uses a flexible buffer layer to buffer the impact of gangue on the goaf side and a rigid skeleton layer to buffer the huge lateral pressure.

[0022] Preferably, the rigid frame layer includes U-shaped steel, with multiple sections of U-shaped steel fixed vertically so that their two ends are respectively embedded in the roadway roof and floor, and multiple sets of U-shaped steel in the horizontal direction are connected and fixed by tie rods.

[0023] Preferably, the flexible buffer layer includes a metal mesh, a ventilation duct cloth, and a steel mesh, which are fixed together by wire to form the flexible buffer layer.

[0024] Preferably, the metal mesh has a double-layer structure.

[0025] Preferably, the reinforcing mesh is formed by welding reinforcing bars.

[0026] The preferred method for reinforcing the support is to install horizontal bracing units between the solid coal face and the U-shaped steel.

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention reinforces the surrounding rock of the roadway in the early stage through various support structures. The constant resistance large deformation anchor cable maintains a constant support force while releasing energy through the sliding of the locking device inside the constant resistance device during the roof sinking process. The flexible buffer layer absorbs the impact kinetic energy of the gangue, and the rigid skeleton layer can slide controllably under a certain torque force of the cable clamping, which can buffer the roof pressure. The transverse support device applies active and adjustable transverse support force to the gangue retaining support, dynamically balances the lateral pressure of the goaf, and combines local transverse bracing units to achieve precise reinforcement of stress concentration areas, forming a closed-loop control system from the whole to the part, ensuring the long-term stability of the roadway under violent mining.

[0028] 2. Collaborative control significantly improves stability: Through the "pre-reinforcement of surrounding rock in the roadway - pressure relief by rock retaining structure - active regulation of support system" system, asymmetric anchor cable support, support frame support and rock retaining support are organically linked to form a closed-loop control system that dynamically responds to changes in surrounding rock. This solves the problem of isolation and passivity in traditional support and greatly improves the overall stability of the roadway.

[0029] 3. High safety and reliability: The "controllable pressure relief" design of the rock retaining support can effectively absorb and dissipate mining impact energy and prevent sudden structural failure; the lateral support device provides active lateral support force to dynamically compensate for surrounding rock deformation, which greatly enhances the reliability and safety of the system under complex loads.

[0030] 4. Significant economic benefits: The method of this invention does not require expensive roadway backfill materials, is easy to construct, saves costs and construction time, and improves mine production efficiency and resource recovery rate. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the planar structure of the roof cutting and roadway retention support combined with the rock retaining support in an embodiment of the present invention; Figure 2 This is a top view schematic diagram of the combined rockfill retaining and support structure of the roof cutting and roadway retention method in an embodiment of the present invention; Figure 3 This is a schematic diagram of the planar structure of the rock-blocking support in an embodiment of the present invention; Figure 4 This is a top view schematic diagram of the rock-blocking support structure in an embodiment of the present invention; Figure 5 This is a top view schematic diagram of the transverse resistance anchor cable support in an embodiment of the present invention; Figure 6 This is a top view of the transverse support device of the stacked bracket in an embodiment of the present invention. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. It should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0034] according to Figures 1-6 As shown, the present invention provides a method for constructing a roof-cutting and roadway-retaining support system in conjunction with rockfill retaining support, specifically including the following steps: S1. Asymmetric anchor cable support 10 is provided on the side of the solid coal seam; the asymmetric anchor cable support 10 includes at least two rows of anchor cable support, the two rows of anchor cable support include a first row of support 11 and a second row of support 12, both the first row of support 11 and the second row of support 12 include anchor cables 13 and I-beams 14, the difference between the first row of support 11 and the second row of support 12 is that the construction method of the anchor cables 13 is different.

[0035] The specific construction method is as follows: The first row of supports 11 is constructed by anchoring cables 13 at a 75° angle to the vertical line towards the bottom plate, with the hole opening 1200mm from the bottom plate; the second row of supports 12 is constructed by anchoring cables 13 perpendicular to the solid coal face, with the hole opening 2200mm from the bottom plate; all anchor cables 13 are fixed to the solid coal face by I-beams 14; the horizontal spacing between the anchor cables 13 of the first row of supports 11 and the second row of supports 12 is 900mm.

[0036] The anchor cable 13 is made of Φ22×4300mm high-strength prestressed steel strand with a designed preload of 100kN; the I-beam 14 is a mining type 11 with a length of 4000mm, and its function is to fix the anchor cable 13.

[0037] S2. Constant resistance anchoring support 20 is provided for the roadway roof. The constant resistance anchoring support 20 supports the roadway roof in at least 4 rows, with the row closest to the top-cutting hole 1 being the first row. The distance between the first row and the top-cutting hole 1 is 300mm. The second, third and fourth rows are arranged in sequence away from the top-cutting hole 1, with a row spacing of 1200mm.

[0038] The constant resistance anchor support 20 includes constant resistance large deformation anchor cables 21 and channel steel 22. The constant resistance large deformation anchor cables 21 are fixed to the top plate by the channel steel 22. The spacing of the first row of constant resistance large deformation anchor cables 21 is 900mm, and the spacing of the second to fourth rows of constant resistance large deformation anchor cables 21 is 1800mm.

[0039] according to Figure 5 As shown, the constant-resistance large-deformation anchor cable 21 has specifications of Φ22×13500mm, a preload of 250kN, and is equipped with a 500mm long constant-resistance device 23 and a locking device 24. The locking device 24 is fixed to the channel steel 22 and the roof plate, and the constant-resistance device 23 is installed at the bottom of the constant-resistance large-deformation anchor cable 21. Pressure relief is achieved by the sliding of the locking device 24 within the constant-resistance device 23. The specific principle is as follows: During the construction of the constant-resistance large-deformation anchor cable 21, the preload is 250kN. When the roadway roof subsides, the position of the roof anchoring section remains unchanged. The locking device 24 slides upward within the constant-resistance device 23, generating pressure relief in the roof plate while maintaining the rated anchor cable preload.

[0040] The channel steel 22 is of type 20# and has a length of 2500mm. It is used to connect the constant resistance large deformation anchor cables 21 in the same row to form a constant resistance anchor support 20 that forms an integral load-bearing structure.

[0041] S3. A support structure 30 is installed between the floor and roof of the roadway. The support structure 30 is installed in at least three rows along the roadway direction. The support structure 30 includes a hydraulic unit 31 and a support I-beam 32. The hydraulic unit 31 is fixed to the floor, and its top is fixedly connected to the roof through the support I-beam 32. The support I-beam 32 is a mining type 11# with a length of 4000mm. The hydraulic unit 31 and the support I-beam 32 further strengthen the support of the roof and control the delamination or uneven deformation of the roof.

[0042] S4. Support the side of the roadway cut-off line with a support 40; the support 40 is a stacked support 41, the stacked support 41 is arranged in a row along the roadway with a center distance of 2000mm, and the distance between the stacked support 41 and the cut-off hole 1 is 500mm.

[0043] The stack-type support 41 has a length of 1500mm, a top beam width of 600mm, a working height of 2600mm~4000mm, and a working resistance of 4000kN. It is used to strengthen the end of the "short wall beam" structure supporting the top plate.

[0044] S5. Provide rock retaining support 50 to the goaf side; the rock retaining support 50 includes a flexible buffer layer 51 and a rigid frame layer 52, one side of the flexible buffer layer 51 is in close contact with the goaf, and the other side is fixed by the rigid frame layer 52.

[0045] The flexible buffer layer 51 includes a metal mesh 511, a ventilation duct cloth 512, and a steel mesh 513. The metal mesh 511, ventilation duct cloth 512, and steel mesh 513 are fixed together by iron wire to form the flexible buffer layer 51. The metal mesh 511 of the flexible buffer layer 51 is closely attached to the sidewall of the goaf. The metal mesh 511 is a double-layer 10# iron mesh. The steel mesh 513 is formed by welding steel bars. The mesh size is 100×100mm, and the diameter of the steel bars is 6mm.

[0046] The rigid frame layer 52 is arranged in a row along the edge of the flexible buffer layer 51. The rigid frame layer 52 includes two U-shaped steel sections, which are divided into an upper U-shaped steel section 521 and a lower U-shaped steel section 522. The upper U-shaped steel section 521 and the lower U-shaped steel section 522 are fixedly connected vertically by two sets of clamping cables 523. The two sets of clamping cables 523 are fixed by bolts, and a pre-tightening torque of 100 N·m is applied to form the two U-shaped steel sections into a whole. When the roadway roof moves downward, the upper U-shaped steel section 521 will slide downward, forming a controllable pressure relief node. The spacing between adjacent U-shaped steel sections in the row is 500 mm.

[0047] A steel plate 524 is welded to the end of the upper U-shaped steel section 521, and a steel pipe 525 is welded to the top of the steel plate 524. The steel pipe 525 is embedded in the top-cut hole 1, and the diameter of the steel pipe 525 is 22mm. The steel plate 524 has through holes, and the anchor rod 526 anchors the upper U-shaped steel section 521 to the top plate. The lower U-shaped steel section 522 is fixed in the foundation pit 2 with an excavation depth of not less than 500mm, specifically buried in the foundation pit 2 to ensure the stability of the support.

[0048] Tie rods 527 are installed on the upper U-shaped steel section 521 that are horizontally adjacent, and two rows of tie rods 527 are installed on the lower U-shaped steel section 522 that are horizontally adjacent, so that multiple sets of U-shaped steels form an integral load-bearing structure.

[0049] S6. The support frame 40 is equipped with a transverse support device 60, which is connected to the rock-blocking support 50, as detailed below. Figure 6 As shown, the lateral support device 60 includes a hydraulic cylinder 61 and a claw 611. One end of the hydraulic cylinder 61 is fixed to the stack-type support 41, and the other end is a telescopic end, which is fixedly connected to the claw 611. The claw 611 is fixed on the lateral I-beam 62. The lateral I-beam 62 is fixedly connected to the lower U-shaped steel 522. The lateral I-beam 62 is a mining type 11# with a length of 4000mm. The hydraulic cylinder 61 applies an active and adjustable lateral support force to the rock retaining support 50.

[0050] S7. A reinforcing support 70 is installed between the solid coal sidewall and the rock retaining support 50. The reinforcing support 70 includes a horizontal brace unit 71 and a horizontal brace I-beam 72. One end of the horizontal brace unit 71 is pressed against the support steel strip of the solid coal sidewall of the roadway, and the other end is pressed against the upper U-shaped steel 521 through the horizontal brace I-beam 72. The horizontal brace I-beam 72 is a mining No. 11 type with a length of 4000mm. The reinforcing support 70 forms a point-to-point reinforcing structure support between the solid coal sidewall and the rock retaining support 50.

[0051] The working principle of the roof-cutting and roadway-retention support combined with the rock-blocking support constructed according to the present invention is as follows: This invention is based on a collaborative dynamic control logic of "pressure relief-reinforcement-pressure yielding-active regulation". It reconstructs the stress transmission path of the overlying strata through directional roof cutting technology, transferring the roadway from a high-stress coal pillar area to a relatively low-stress region, achieving fundamental pressure relief. Simultaneously, anchor cables are used for early active reinforcement of the surrounding rock, forming a high-strength support system that safely dissipates deformation energy through a multi-stage pressure yielding mechanism: constant-resistance large-deformation anchor cables 22 release energy through constant-resistance devices 23 while maintaining a constant support force; the U-shaped steel cable clamps 523 allow controllable sliding at their connection nodes under a set torque force, buffering roof pressure; and a flexible buffer layer 51 further absorbs the impact energy of gangue. Finally, the transverse support device 60 of the stacked support 21 applies active and adjustable transverse support force to the gangue retaining support 50, dynamically balancing the lateral pressure of the goaf area. Combined with local transverse support units 71, precise reinforcement of stress concentration areas is achieved, forming a closed-loop control system from the overall system to the local level, ensuring the long-term stability of the roadway under intense mining conditions.

[0052] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for constructing a roof-cutting and roadway-retaining support system in conjunction with rockfill retaining support, characterized in that, Includes the following steps: Asymmetric anchor cable support is used for the solid coal seam, constant resistance anchor cable support is used for the roadway roof, support is installed between the roadway floor and roof, bracket support is used on the roadway roof cutting line side, and rock retaining support is used for the goaf area; the bracket support is equipped with lateral support devices, which are connected with the rock retaining support to form lateral constraints, and reinforcement support is installed between the solid coal seam and the rock retaining support.

2. The construction method of the top-caving and roadway-protecting support coordinated with the gangue-blocking support according to claim 1, characterized in that, The asymmetric anchor cable support includes at least two rows, consisting of a first row and a second row. The distance between the first and second rows is 1000mm. The first row is constructed by anchoring the cables at a certain angle to the plumb line towards the solid coal face. The second row is constructed by anchoring the cables perpendicular to the solid coal face, with a horizontal spacing of 900mm.

3. The construction method of roof cutting and roadway retention support combined with rock retaining support according to claim 1, characterized in that, Specific operation of constant resistance anchor cable support: constant resistance large deformation anchor cables and channel steel are used to support the roof of the roadway. The constant resistance large deformation anchor cables are equipped with constant resistance devices and locking devices.

4. The construction method of the top-caving and roadway-protecting support coordinated with the gangue-blocking support according to claim 1, characterized in that, Specific operation of support: Hydraulic monoliths and I-beams are used to vertically support the roadway between the roof and floor.

5. The construction method of the top-caving and roadway-protecting support coordinated with the sheared coal blocking support according to claim 1, characterized in that, Specific operation of the support system: Install stack-type supports to support the top plate on the side of the cut-off line. The stack-type supports are equipped with transverse support devices, which are connected to the rock retaining support.

6. The construction method of the top-caving and roadway-protecting support coordinated with the sheared coal blocking support according to claim 5, characterized in that, The lateral support device includes a hydraulic cylinder and a claw. One end of the hydraulic cylinder is fixed to the stack-type support, and the other end is a telescopic end. The telescopic end is connected to the rock retaining support through the claw.

7. The construction method of the top-caving and roadway-keeping support coordinated with the sheared coal blocking support according to claim 1, characterized in that, The rock retaining support includes a flexible buffer layer and a rigid skeleton layer. One side of the flexible buffer layer is close to the goaf, and the other side is fixed by the rigid skeleton layer.

8. The construction method of the top-caving and roadway-keeping support coordinated with the sheared coal blocking support according to claim 7, characterized in that, The rigid frame layer includes U-shaped steel sections, which are fixed vertically so that their ends are embedded into the roadway roof and floor respectively. Multiple sets of U-shaped steel sections are connected and fixed horizontally by tie rods.

9. The construction method of roof cutting and roadway retention support combined with rock retaining support according to claim 7, characterized in that, The flexible buffer layer consists of a metal mesh, a ventilation duct cloth, and a steel mesh. The metal mesh, ventilation duct cloth, and steel mesh are fixed together with iron wire to form the flexible buffer layer. The metal mesh has a double-layer structure. The steel mesh is formed by welding steel bars.

10. The construction method of roof cutting and roadway retention support combined with rock retaining support according to claim 8, characterized in that, Specific operation for reinforcement support: Install horizontal bracing units between the solid coal face and the U-shaped steel.

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