Underground coal mine cantilever retractable support and supporting method

Abstract

The invention discloses an underground coal mine cantilever retractable support and a supporting method, the underground coal mine cantilever retractable support comprises a shoulder nest beam, a leg beam, a cable clamping device and a pull rod, the shoulder nest beam and the leg beam are connected through the cable clamping device to form a group of cantilever type supports, the lower end of the leg beam is fixedly connected to the ground, and the multiple groups of cantilever type supports are uniformly arranged in the length direction of a roadway; the multiple cantilever type supports are fixedly connected through pull rods to form the whole support. According to the method, the local deformation position of the roadway is repaired, the arc-shaped beam, the straight leg part and the radian and length of the leg beam in the shoulder pit beam are adjusted to adapt to the deformed part of the roadway, the roadway maintenance work amount is reduced, the roadway expansion range is reduced, and the roadway surrounding rock loosening circle development range is narrowed; a plurality of groups of pull rods are used for interlocking a plurality of groups of cantilever type retractable supports to form a whole support, large support strength and support rigidity can be provided to adapt to surrounding rock deformation, meanwhile, the support has retractability, and the service life of a roadway support is ensured.

Description

Technical Field

[0001] The invention relates to the technical field of underground coal mine supports, and in particular to an underground coal mine cantilever retractable support and a supporting method. Background Art

[0002] The underground tunnel space in coal mines is the basic guarantee for safe production of mines and one of the important conditions for maintaining the stability and safety of mines. However, under the conditions of high ground stress, "three soft" coal seams, excavation along the goaf, and the influence of mining, problems such as aggravated tunnel deformation, difficult support, and high maintenance frequency restrict the high-quality development of mines. The contradictory relationship between high-quality development of mines and safe production has become particularly complex and urgent. Maintaining the long-term stability of the tunnel has become the key.

[0003] Most of the mines in southwest my country are mined in close proximity to each other in coal seams, and most of them are coal and gas outburst coal seams. Coal and gas outburst accidents are prevented by mining protective layers and digging tunnels along the goaf. There are many factors affecting tunnel deformation and damage, usually one factor is dominant and multiple factors are mixed, resulting in large differences in the degree of damage at different locations of the tunnel. Under the influence of high ground stress, the characteristics of "three soft" tunnel surrounding rock, such as large deformation, fast deformation rate and long duration, gradually emerge.

[0004] With the continuous development of support theory and support technology, the concept of tunnel support has changed from passive support to active support, and more attention has been paid to the combined support method of improving support resistance, support strength and support density, so as to form a combined support as a whole to change the stress state of the tunnel surrounding rock. At present, under the influence of complex stresses such as goaf and mining, large-scale stress concentration occurs on both sides of the tunnel due to the developed bedding, poor stability and low rock strength of the top and bottom strata. The maximum stress value on the coal pillar side is greater than the maximum stress value on the solid coal side, showing a large local deformation of the tunnel with asymmetric size and range, and its support and repair have become difficulties and key points. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a retractable cantilever support and a supporting method for an underground coal mine, so as to solve the technical problems existing in the prior art.

[0006] The technical solution adopted by the present invention is: a retractable cantilever support in a coal mine underground, comprising a shoulder beam, a leg beam, a cable clamping device and a pull rod, the shoulder beam and the leg beam are connected by a cable clamping device to form a group of cantilever supports, the lower end of the leg beam is fixedly connected to the ground, multiple groups of cantilever supports are adopted, and they are evenly arranged along the length direction of the tunnel, and the multiple groups of cantilever supports are fixedly connected by pull rods to form an integral support.

[0007] Furthermore, the above-mentioned cantilever retractable support in underground coal mines also includes a plurality of anchor cable beams, which form an integral cantilever support and are fixedly connected to the inner surface of the tunnel, and the anchor cable beams are close to the pull rod and are located below the pull rod.

[0008] Furthermore, the above-mentioned anchor cable beam includes a lock, an anchor cable, an I-beam and an anchor plate. One side of the I-beam rests against one side of the shoulder beam or the leg beam, and the other side rests against the anchor plate. The anchor plate is penetrated by an anchor cable and locked with a lock. The anchor cable is fixedly embedded in the anchor cable hole set in the tunnel.

[0009] Furthermore, two groups of anchor cable beams are arranged at the top of the shoulder socket beam and near the upper middle part, and the two groups of anchor cable beams are arranged in a staggered manner.

[0010] Furthermore, a group of anchor beams are arranged near the bottom of the leg beams.

[0011] Furthermore, the shoulder socket beam comprises an arc-shaped beam and a straight leg portion; the lower end of the arc-shaped beam and the upper end of the straight leg portion are fixed as an integral structure; the arc-shaped beams are fixedly connected by two tie rods, one tie rod is arranged at the top of the arc-shaped beam, and the other tie rod is arranged in the middle of the arc-shaped beam.

[0012] Furthermore, each of the arc-shaped beams is provided with a connecting ear, and the pull rod is a threaded rod, which is locked with a double nut after passing through the connecting ear.

[0013] Furthermore, the leg beam comprises two straight leg parts and a leg plate, the lower end of the two straight leg parts is fixedly connected with the leg plate, the leg plate is provided with a mounting through hole for fixing, the two straight leg parts are fixedly connected by a pull rod, and the pull rod is arranged near the middle of the arc beam.

[0014] Furthermore, a plurality of iron back plates are arranged along the length direction between the shoulder beam and the leg beam and the tunnel rock mass.

[0015] A construction method for a cantilever retractable support in a coal mine. The method comprises the following steps: after a severely deformed tunnel is excavated or dug, the tunnel is in an unsupported state, a cantilever retractable support is installed, and a top column or a point anchor is used for temporary fixation, an iron back plate is evenly arranged between the retractable support and the rock mass, an upper pull rod, a middle pull rod, and a lower pull rod are installed on the retractable support and tightened to initially form a whole, and then anchor cables are constructed to assist in fixing the retractable support, an I-beam is installed to ensure that the anchor cables pass through the anchor cable eyes of the I-beam, and three groups of I-beams are located below the upper pull rod, the middle pull rod, and the lower pull rod, an anchor plate and a lock are installed, and the anchor cables are tightened to make the retractable support close to the rock mass under the action of the anchor cable preload, and the anchor cable beams are staggered to form an active and passive combined support as a whole.

[0016] Beneficial effects of the present invention: Compared with the prior art, the present invention repairs the local deformed position according to the deformation characteristics of the tunnel, and adapts to the deformed part of the tunnel by adjusting the arc beam, the straight leg part, and the curvature and length of the leg beam in the shoulder beam, thereby reducing the maintenance work of the tunnel, reducing the tunnel expansion range, and reducing the development range of the loose circle of the tunnel surrounding rock. The shoulder beam and the leg beam are connected by a cable clamping device, and multiple groups of cantilever retractable brackets are interlocked by multiple groups of pull rods to form a supporting whole, and can provide greater support strength and support stiffness to adapt to the deformation of the surrounding rock. At the same time, the support is retractable to ensure that the service cycle is extended when the tunnel is deformed again. The support processing, installation, and recovery are relatively simple, and the tunnel expansion work is reduced, which can effectively improve the utilization rate of the tunnel section and reduce the support cost. Active support is carried out by using anchor cable beams to compress the surrounding rock, thereby improving the integrity and strength of the rock mass, effectively controlling the displacement of the rock mass and promoting its stability. Through the anchoring effect of the anchor cable and the I-beam fixed cantilever retractable support, the overall performance of the cantilever retractable support is improved, and the support strength and support stiffness of the retractable support are fully utilized. The surrounding rock stress is evenly distributed on the support joint body through the I-beam and iron back plate, ensuring that the overall force of the joint support is uniform, which can effectively prevent local deformation from inducing large-area support failure. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the front view structure of a cantilever retractable support in a coal mine; Figure 2 It is a schematic diagram of the side view structure of a cantilever retractable support in an underground coal mine; Figure 3 It is a schematic diagram of the shoulder socket beam structure; Figure 4 It is a schematic diagram of the leg beam structure; Figure 5 It is a schematic diagram of the anchor hole structure; Figure 6 It is a schematic diagram of the anchor beam structure. DETAILED DESCRIPTION

[0018] The present invention is further described below in conjunction with specific embodiments.

[0019] Example 1: Figure 1-6 As shown, a retractable cantilever support in a coal mine comprises a shoulder beam 1, a leg beam 2, a cable clamping device 3 and a pull rod 4. The shoulder beam 1 and the leg beam 2 are connected by the cable clamping device 3 to form a group of cantilever supports. The lower end of the leg beam 2 is fixedly connected to the ground. A plurality of cantilever supports are used, which are evenly arranged along the length direction of the tunnel. The plurality of cantilever supports are fixedly connected by the pull rod 4 to form an integral support. The cable clamping device 3 uses a plurality of clamping cables.

[0020] In order to further improve the stability of the support, a retractable cantilever support in a coal mine also includes multiple anchor beams 5. The multiple anchor beams 5 will form an integral cantilever support fixedly connected to the inner surface of the tunnel, which can further improve the integrity of the support structure, with better rigidity and strength, and better stability. The anchor beams 5 are close to the pull rods 4 and are located below the pull rods 4. The pull rods can provide a limiting effect for the anchor beams 5, limiting the displacement of the anchor beams 5 during the pre-tightening and pressure process after the construction is completed, ensuring the cantilever The retractable bracket is evenly stressed as a whole; the anchor beam 5 includes a lock 501, an anchor cable 502, an I-beam 503 and an anchor plate 504. One side of the I-beam 503 abuts against one side of the shoulder beam 1 or the leg beam 2, and the other side abuts against the anchor plate 504. The anchor plate 504 is penetrated by an anchor cable 502 and locked by a lock 501. The anchor cable 502 is fixedly embedded in an anchor cable hole 505 set in the tunnel; a plurality of iron back plates 6 are arranged along the length direction between the shoulder beam 1 and the leg beam 2 and the tunnel rock mass. The anchor beam 5 is used for active support to put the surrounding rock in a compacted state, thereby improving the integrity and strength of the rock mass, effectively controlling the displacement of the rock mass, and promoting its stability. The cantilever retractable support is fixed by the anchoring effect of the anchor cable 502 and the I-beam 503, so as to improve the overall performance of the cantilever retractable support and give full play to the support strength and support stiffness of the retractable support. The surrounding rock stress is evenly distributed on the support combination through the I-beam 503 and the iron back plate 6, so as to ensure that the overall force of the combined support is uniform, and effectively prevent local deformation from inducing large-area support failure. In order to improve the support effect, two groups of anchor cable beams 5 are arranged at the top of the shoulder beam 1 and near the middle and upper part, and the two groups of anchor cable beams 5 are staggered. One group of anchor cable beams 5 is arranged near the bottom of the leg beam 2.

[0021] Among them, the shoulder socket beam 1 includes an arc-shaped beam 101 and a straight leg portion 104. The lower end of the arc-shaped beam 101 and the upper end of the straight leg portion 102 are fixed as an integrated structure. The arc-shaped beams 101 are fixedly connected by two tie rods 4. One tie rod 4 is arranged at the top of the arc-shaped beam 101, and the other tie rod 4 is arranged in the middle of the arc-shaped beam 101. In order to facilitate the installation of the tie rod, each arc-shaped beam 101 is provided with a connecting ear 103. The tie rod 4 is a threaded rod, which is locked with a double nut after passing through the connecting ear 103. The structure is easy and quick to install, and multiple tie rods are tightened, and the overall support is better.

[0022] Among them, the leg beam 2 includes a straight leg part 201 and a leg plate 202. The lower end of the straight leg part 201 is fixedly connected to the leg plate 202. The leg plate 202 is provided with a mounting through hole for fixing. The straight leg parts 201 are fixedly connected by a tie rod 4. The tie rod 4 is arranged near the middle of the arc beam 101. The structure is easy and quick to install, the tie rod is tightened, and the overall support is better. The straight leg part 201 is also provided with a connecting ear for connecting the tie rod.

[0023] By designing a cantilever retractable support, the rigidity and strength of the tunnel lateral pressure deformation section support are improved, and multiple sets of tie rods are interlocked to form a support as a whole. Anchor cables and I-beams are combined into an anchor cable beam structure to improve the stress state of the surrounding rock and achieve tunnel lateral pressure deformation control, thereby reducing the deformation rate of the two sides of the tunnel under complex stress, thereby extending the tunnel service cycle, reducing the amount of shaft and tunnel maintenance work, and ensuring the space required for safe production in the mine.

[0024] Embodiment 2: A construction method of a cantilever retractable support in a coal mine, the method comprising: after the tunnel with severe deformation is excavated or dug, the tunnel is in an unsupported state, a cantilever retractable support is installed, and it is temporarily fixed by means of top columns or point anchors, an iron back plate is evenly arranged between the retractable support and the rock mass, the upper pull rod, the middle pull rod, and the lower pull rod are installed on the retractable support and tightened to initially form a whole, and then anchor cables are constructed to assist in fixing the retractable support, I-beams are installed to ensure that the anchor cables pass through the anchor cable eyes of the I-beams, and three groups of I-beams are located below the upper pull rod, the middle pull rod, and the lower pull rod, anchor plates and locks are installed, and the anchor cables are tightened so that the retractable support is close to the rock mass under the action of the anchor cable preload, and the anchor cable beams are staggered to form an active and passive combined support as a whole.

[0025] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention 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 invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A retractable cantilever support for underground coal mines, characterized in that: The invention comprises a shoulder beam (1), a leg beam (2), a cable clamping device (3) and a pull rod (4); the shoulder beam (1) and the leg beam (2) are connected via the cable clamping device (3) to form a group of cantilever brackets; the lower end of the leg beam (2) is fixedly connected to the ground; a plurality of cantilever brackets are used and are evenly arranged along the length direction of the tunnel; the plurality of cantilever brackets are fixedly connected via the pull rod (4) to form an integral bracket.

2. The retractable cantilever support for underground coal mines according to claim 1, characterized in that: It also includes a plurality of anchor cable beams (5), which form a cantilever bracket that is fixedly connected to the inner surface of the tunnel. The anchor cable beams (5) are closely attached to the pull rod (4) and are located below the pull rod (4).

3. A retractable cantilever support for underground coal mines according to claim 1 or 2, characterized in that: The anchor cable beam (5) comprises a lock (501), an anchor cable (502), an I-beam (503) and an anchor plate (504); one side of the I-beam (503) abuts against one side of the shoulder beam (1) or the leg beam (2), and the other side abuts against the anchor plate (504); the anchor cable (502) is inserted into the anchor plate (504) and is locked with the lock (501); the anchor cable (502) is fixedly embedded in an anchor cable hole provided in the tunnel.

4. The retractable cantilever support for underground coal mines according to claim 3, characterized in that: Two groups of anchor cable beams (5) are arranged at the top and near the upper middle portion of the shoulder socket beam (1), and the two groups of anchor cable beams (5) are arranged in a staggered manner.

5. The retractable cantilever support for underground coal mines according to claim 4, characterized in that: A group of anchor beams (5) are arranged near the bottom of the leg beam (2).

6. The retractable cantilever support for underground coal mines according to claim 4, characterized in that: The shoulder socket beam (1) comprises an arc-shaped beam (101) and a straight leg portion (104); the lower end of the arc-shaped beam (101) and the upper end of the straight leg portion (102) are fixed to form an integral structure; the arc-shaped beams (101) are fixedly connected by two tie rods (4); one tie rod (4) is arranged at the top of the arc-shaped beam (101), and the other tie rod (4) is arranged at the middle of the arc-shaped beam (101).

7. The retractable cantilever support for underground coal mines according to claim 4, characterized in that: Each arc-shaped beam (101) is provided with a connecting ear (103), and the pull rod (4) is a threaded rod that passes through the connecting ear (103) and is locked with a double nut.

8. A retractable cantilever support for underground coal mines according to claim 1 or 2, characterized in that: The leg beam (2) comprises a second straight leg portion (201) and a leg plate (202); the lower end of the second straight leg portion (201) is fixedly connected to the leg plate (202); a mounting through hole for fixing is provided on the leg plate (202); the second straight leg portion (201) is fixedly connected by a tie rod (4); the tie rod (4) is arranged near the middle of the arc-shaped beam (101).

9. A retractable cantilever support for underground coal mines according to claim 1 or 2, characterized in that: A plurality of iron back plates (6) are arranged along the length direction between the shoulder beam (1) and the leg beam (2) and the tunnel rock mass.

10. The construction method of a cantilever retractable support in a coal mine according to claim 1, characterized in that: The method is as follows: after the tunnel with serious deformation is excavated or dug, the tunnel is in an unsupported state, a cantilever retractable support is installed, and it is temporarily fixed by means of top columns or point anchors, and iron back plates are evenly arranged between the retractable support and the rock mass, and the upper tie rod, the middle tie rod, and the lower tie rod are installed on the retractable support and tightened to initially form a whole, and then anchor cables are constructed to assist in fixing the retractable support, and I-beams are installed to ensure that the anchor cables pass through the anchor cable eyes of the I-beams, and the three groups of I-beams are located below the upper tie rod, the middle tie rod, and the lower tie rod, and anchor plates and locks are installed, and the anchor cables are tightened so that the retractable support is close to the rock mass under the action of the anchor cable preload, and the anchor cable beams are staggered to form an active and passive combined support as a whole.

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