Deep soft rock gob-side entry retaining surrounding rock control method

Abstract

The invention relates to the technical field of coal mine roadway gob-side entry retaining surrounding rock control, and provides a deep soft rock gob-side entry retaining surrounding rock control method which comprises the steps that after a working face is stoped by a preset distance, a pi-shaped steel beam is arranged on a top plate of a stoping working face roadway, and a supporting wall is poured on one side of the stoping working face roadway; the top of the supporting wall abuts against the pi-shaped steel beam; and a component is laid along the center line of the roadway of the stope face, a plurality of supporting pier studs are poured in the extension direction of the length of the component, and the tops of the supporting pier studs abut against the pi-shaped steel beams. According to the deep soft rock gob-side entry retaining surrounding rock control method, the supporting wall body and the supporting pier columns jointly bear the load of the top plate, wall column collaborative supporting greatly improves the strength of roadway supporting, the pressure of the supporting wall body is relieved, the overall supporting effect of a roadway is improved, the supporting pier columns change the stress structure of the roadway, the span of the roadway is obviously reduced, and the working efficiency of the roadway is improved. The span is reduced, so that the bottom plate can bear larger horizontal stress, the bending moment is obviously reduced, and the bottom heave amount is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of surrounding rock control for gob-side retained lanes in coal mine tunnels, and in particular to a method for controlling surrounding rock for gob-side retained lanes in deep soft rock. Background Art

[0002] The mining depth of coal mines in my country has increased year by year. The stress of surrounding rock has increased in deep mining. Under the condition of gob-side tunnel retention, tunnel deformation has gone through three stages: advanced deformation, lagging deformation and secondary mining deformation. In deep soft rock tunnels, weak surrounding rock generally shows large deformation and instability under the influence of high stress and strong mine pressure. The existing support technology mostly adopts anchor grouting support, which has insufficient support strength, poor support effect, and large tunnel maintenance, which seriously restricts the efficient and safe production of the working face. Summary of the invention

[0003] The invention provides a method for controlling surrounding rock of deep soft rock gob-side tunnel retaining, which is used to solve the defect of poor anchor-grouting support effect of soft surrounding rock under the influence of high stress and strong mine pressure in the prior art.

[0004] The present invention provides a method for controlling surrounding rock of a deep soft rock gob-side lane retaining, comprising: after the working face is mined for a preset distance, arranging a π-shaped steel beam on the top plate of the laneway of the mining working face, casting a supporting wall on one side of the laneway of the mining working face, and making the top of the supporting wall abut against the π-shaped steel beam; laying components along the center line of the laneway of the mining working face, casting a plurality of supporting piers along the extension direction of the length of the components, and making the top of the supporting piers abut against the π-shaped steel beam.

[0005] According to a method for controlling surrounding rock of a deep soft rock gob-side entry provided by the present invention, the step of laying components along the center line of the mining face tunnel further includes: opening a first groove on the bottom plate of the mining face tunnel along the center line of the mining face tunnel, burying the component in the first groove, and filling the first groove with concrete.

[0006] According to a method for controlling surrounding rock of a deep soft rock gob-side entry provided by the present invention, a first groove is opened on the bottom plate of the mining face tunnel along the center line of the mining face tunnel, and the step of burying the component in the first groove further includes: arranging multiple pairs of I-beams along the extension direction of the length of the first groove, and splicing or overlapping the multiple pairs of I-beams in sequence.

[0007] According to a method for controlling surrounding rock of a deep soft rock gob-side tunnelling provided by the present invention, a plurality of pairs of I-beams are arranged along the extension direction of the length of the first groove, and the step of overlapping the plurality of pairs of I-beams in sequence further includes: arranging some pairs of I-beams in parallel among the plurality of pairs of I-beams, arranging the remaining pairs of I-beams close together, and arranging the I-beams arranged in parallel and the I-beams arranged close together alternately; and inserting the two ends of the I-beams arranged close together into the I-beams arranged in parallel.

[0008] A method for controlling surrounding rock of a deep soft rock gob-side entry retaining provided by the present invention also includes: before laying a plurality of pairs of I-beams in the first groove, casting the first groove once; after the first groove is filled with the I-beams, casting the first groove a second time until the first groove is filled.

[0009] According to a method for controlling surrounding rock of a deep soft rock gob-side entry retaining provided by the present invention, the step of casting a plurality of supporting piers along the extension direction of the length of the component further includes: casting the supporting piers at the splicing or overlapping of two adjacent pairs of I-beams; after a plurality of pairs of I-beams are spliced ​​or overlapped into an integral frame, casting the supporting piers at both ends of the integral frame, wherein the diameter of the supporting piers is greater than the spacing between a pair of parallel I-beams.

[0010] According to a method for controlling surrounding rock of a deep soft rock gob-side tunnelling provided by the present invention, the step of casting supporting piers includes: after the first groove is fully cast and solidified, a plurality of restraining sleeves are arranged on the first groove along the extension direction of the length of the first groove, and a first steel mesh cage is pre-installed in the restraining sleeve; concrete is poured into the restraining sleeve to form the supporting pier.

[0011] A surrounding rock control method for deep soft rock gob-side entry retaining provided by the present invention also includes: arranging a plurality of pairs of tension anchor rods along the extension direction of the length of each of the supporting piers.

[0012] According to a method for controlling surrounding rock of a deep soft rock gob-side tunnel provided by the present invention, the step of casting a supporting wall on one side of a tunnel of a mining face comprises: hanging a flexible formwork at a preset position on the top plate of the tunnel of the mining face, wherein a second steel mesh cage is pre-installed in the flexible formwork; and pouring concrete into the flexible formwork to form the supporting wall.

[0013] A method for controlling surrounding rock of a deep soft rock gob-side entry retaining provided by the present invention also includes: opening a second groove at a preset position of the bottom plate and pouring concrete, and pouring the supporting wall on the second groove after the concrete solidifies.

[0014] The method for controlling surrounding rock of deep soft rock gob-side tunneling provided by the present invention casts supporting walls and supporting piers, and the supporting walls and supporting piers jointly bear the roof load. The coordinated support of the walls and columns greatly improves the strength of tunnel support, reduces the pressure of the supporting walls, reduces the pressure on the tunnel side, and improves the overall support effect of the tunnel. The supporting piers divide the tunnel in the middle, which significantly reduces the span of the tunnel floor. The reduction in the span of the floor allows the floor to withstand greater horizontal stress, significantly reduces the bending moment of the floor, and the bulging range of the floor is reduced accordingly, which can significantly reduce the amount of floor bulging. The supporting walls and piers support the overall structure formed by the π-shaped beams, which can prevent the weak roof from being cut along the wall, and at the same time strengthen the support for the roof. The method for controlling surrounding rock of deep soft rock gob-side tunneling provided by the present invention can effectively control the large deformation problem of deep soft rock gob-side tunneling, and ensure safe and smooth mining of the mining face. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0016] Figure 1 It is a flow chart of the surrounding rock control method of deep soft rock gob-side entry retaining provided by the present invention.

[0017] Figure 2 This is the main view of the mining face tunnel.

[0018] Figure 3 This is a top view of the mining face tunnel.

[0019] Reference numerals: 1. Mining working face tunnel; 2. Bottom plate; 21. Groove; 3. I-beam; 4. Support wall; 5. Support pier; 6. π-shaped steel beam. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] Combine the following Figure 1-Figure 3 The invention describes a surrounding rock control method for deep soft rock gob-side entry retaining.

[0022] like Figure 1As shown, an embodiment of the present invention provides a method for controlling surrounding rock of a deep soft rock goaf-retained lane, which specifically includes the following steps: Step 100, after the working face is mined for a preset distance, a π-shaped steel beam 6 is set on the top plate of the mining working face tunnel 1, a supporting wall 4 is cast on one side of the mining working face tunnel 1, and the top of the supporting wall 4 is abutted against the π-shaped steel beam 6; Step 200, components are laid along the center line of the mining working face tunnel 1, and a plurality of supporting piers 5 are cast along the extension direction of the length of the components, and the top of the supporting piers 5 is abutted against the π-shaped steel beam 6.

[0023] Specifically, when the working face is mined, two tunnels are usually excavated, one of which is used as an air intake channel and the other as a return air channel to ensure the safety of mining. If, during mining, the mining face tunnel after the coal pillar is mined is retained as one of the tunnels of the new mining face, then when the new mining face is mined, only one more tunnel needs to be excavated, which can provide great convenience for mining. The deep soft rock gob-side tunnel surrounding rock control method provided in the embodiment of the present invention is to retain the mining face tunnel after mining for use as the tunnel of the new mining face.

[0024] Specifically, Figure 2 As shown, usually after the working face is mined for a certain distance, the rear of the working face is in a state of collapse. To prevent the rear of the working face from collapsing, after the working face is mined for a preset distance, a π-shaped steel beam 6 is hung on the top plate of the mining working face tunnel 1, and a support wall 4 is cast on one side of the mining working face tunnel 1, and the top of the support wall 4 is abutted against the π-shaped steel beam 6 to prevent the top plate from rotating and sinking. At the same time, components are laid along the center line of the mining working face tunnel 1, and multiple support piers 5 are cast along the extension direction of the length of the components, and the top of each support pier 5 is abutted against the π-shaped steel beam 6 to strengthen the tunnel support, and the top plate is used to press the bottom plate 2 of the mining working face tunnel 1 to improve the stress environment of the bottom plate. In this embodiment, the π-shaped steel beam 6 can prevent the weak top plate from cutting along the wall when the support wall 4 abuts against the top plate, and can also play a role in strengthening the support of the top plate. The supporting pier 5 and the component form a beam-column structure, which can transfer the pressure of the top plate to the component to prevent the bottom plate 2 from bulging. Furthermore, in this embodiment, the component is arranged on the center line of the mining face tunnel 1, which separates the mining face tunnel 1 from the middle, so that the span of the bottom plate 2 of the mining face tunnel 1 is reduced by 50%. The reduction of the span of the bottom plate 2 can enable the bottom plate 2 to withstand greater horizontal forces, reduce the bending moment of the bottom plate 2, and reduce the bulging range of the bottom plate 2, thereby reducing the bulging amount of the bottom plate 2.

[0025] In this embodiment, the roof movement of the gob-side entry retaining has hysteresis. After the coal body is excavated, the roof behind the working face breaks, rotates and sinks. According to actual engineering experience, the 10-300m behind the working face is the dynamic pressure influence zone. Therefore, when pouring the supporting wall 4 and the supporting pier 5, it is necessary to keep up with the working face and pour the supporting wall 4 and the supporting pier 5 within the range of 0-10m lagging behind the working face to ensure the stability and reliability of the gob-side entry retaining system.

[0026] Optionally, in an embodiment of the present invention, the component may be a steel plate or other steel sections.

[0027] The surrounding rock control method for deep soft rock gob-side tunneling provided by the embodiment of the present invention casts supporting walls and supporting piers, and the supporting walls and supporting piers jointly bear the roof load. The coordinated support of the walls and columns greatly improves the strength of the tunnel support, reduces the pressure of the supporting walls, reduces the pressure on the tunnel side, and improves the overall support effect of the tunnel; the supporting piers divide the tunnel in the middle, significantly reducing the span of the tunnel floor. The reduction in the span of the floor allows the floor to withstand greater horizontal stress, significantly reduces the bending moment of the floor, and the bulging range of the floor is reduced accordingly, which can significantly reduce the amount of floor bulging; the supporting walls and piers support the overall structure formed by the π-shaped beams, which can prevent the weak roof from being cut along the wall, and at the same time play a role in strengthening the support of the roof; the surrounding rock control method for deep soft rock gob-side tunneling provided by the embodiment of the present invention can effectively control the large deformation problem of deep soft rock gob-side tunneling, and ensure the safe and smooth mining of the mining face.

[0028] Furthermore, in an embodiment of the present invention, the step of laying components along the center line of the mining face tunnel 1 further includes: opening a first groove 21 on the bottom plate 2 along the center line of the mining face tunnel 1, burying components in the first groove 21, and filling the first groove 21 with cast.

[0029] Specifically, in this embodiment, the bottom plate 2 of the roadway 1 of the mining working face is soft rock. If components are laid directly on the soft rock, the supporting pier 5 may easily become unstable when the soft rock slides. In order to improve the stability of the supporting pier 5, a first groove 21 is opened on the bottom plate 2, and components are buried in the first groove 21, and then the first groove 21 is filled with concrete. After the concrete in the first groove 21 solidifies, the supporting pier 5 is poured, so that the foundation of the supporting pier 5 is solid, thereby improving the stability of the supporting pier 5.

[0030] In the embodiment of the present invention, the component is an I-beam 3. A plurality of pairs of I-beams 3 are embedded in the first groove 21, and the plurality of pairs of I-beams 3 can be spliced ​​end to end to form an overall frame, or overlapped end to end to form an overall frame. When the supporting piers 5 are cast, the splicing or overlapping of two adjacent pairs of I-beams 3 is cast to compact the connection. At the same time, the supporting piers 5 are cast at both ends of the overall frame to compact the two ends of the overall frame, thereby increasing the pressure on the bottom plate 2, thereby reducing the bulging amount of the bottom plate 2.

[0031] like Figure 3 As shown, when overlapping multiple pairs of I-beams 3 in sequence, some pairs of I-beams 3 can be arranged in parallel, and the remaining pairs of I-beams 3 can be arranged close together, and the parallel I-beams 3 and the close I-beams 3 are arranged alternately. The two ends of the close I-beams 3 are inserted into the parallel I-beams 3, so that the multiple pairs of I-beams 3 can be overlapped.

[0032] Some of the multiple pairs of I-beams 3 are arranged in parallel, and some of the pairs of I-beams 3 are arranged close together. The I-beams 3 arranged in parallel increase the contact area with the bottom plate 2, which can effectively prevent the bottom bulge. The I-beams 3 arranged close together are beneficial to improving the strength of the base, making the supporting pier 5 stable and not prone to instability.

[0033] Furthermore, before laying multiple pairs of I-beams 3 in the first groove 21, the first groove 21 may be cast once. Optionally, in one embodiment of the present invention, the depth of the first groove 21 is 600 mm, and the depth of the first casting may be 400 mm. After the first casting, the I-beam 3 is laid in the first groove 21 according to the above-mentioned overlap method, and then the first groove 21 is cast for the second time, with a casting depth of 200 mm, so that the first groove 21 is filled. In this embodiment, the I-beam 3 and the first groove 21 are cast together, which improves the bending strength of the bottom channel beam formed by the I-beam 3 and the first groove 21, thereby improving the stability of the supporting pier 5. It can be understood that the depth of the secondary casting can also be designed according to the construction conditions.

[0034] In this embodiment, when the I-beams 3 are laid in the first groove 21, the I-beams 3 arranged side by side are respectively located on both sides of the center line of the first groove 21. Optionally, the length of each I-beam 3 is 2800 mm.

[0035] After the first groove 21 is filled, a plurality of supporting piers 5 are cast on the top surface of the first groove 21. The diameter of each supporting pier 5 is larger than the width between a pair of parallel I-beams 3 and smaller than the width of the first groove 21. By casting the first groove 21 twice, the firmness and stability of the base of the supporting pier 5 are improved. At the same time, after the supporting pier 5 is cast, the first groove 21, the I-beam 3 and the supporting pier 5 form a bottom channel beam structure. The buried I-beam 3 can greatly improve the bending and shearing resistance of the bottom channel beam, and can also prevent the bottom channel from bulging under the influence of strong mine pressure.

[0036] It should be noted that if there is equipment operation at the mining face, so that the first groove 21 cannot be opened on the center line of the mining face tunnel 1, the first groove 21 can also be set offset from the center line.

[0037] Further, in an embodiment of the present invention, the step of pouring the supporting pier column 5 includes: after the first groove 21 is poured and solidified, a plurality of restraining sleeves are arranged on the first groove 21 along the extension direction of the length of the first groove 21, the restraining sleeves are rigid molds, and a first steel mesh cage is pre-set in the restraining sleeves. Concrete is poured into the restraining sleeves to form the supporting pier column 5. The first steel mesh cage is arranged in the supporting pier column 5, which can significantly improve the bending resistance of the supporting pier column 5. Optionally, the center distance between two adjacent supporting pier columns 5 is 2000mm, and the diameter of each supporting pier column 5 is 800mm.

[0038] After the supporting pier 5 is cast, a plurality of pairs of tension anchor rods are arranged along the extension direction of the length of each supporting pier 5. The tension anchor rods serve as external constraints of the supporting pier 5 and can significantly improve the strength of the supporting pier 5. In the embodiment of the present invention, the bearing capacity of each supporting pier 5 is above 20,000 KN.

[0039] In an embodiment of the present invention, the step of casting a supporting wall 4 on one side of the mining face tunnel 1 includes: hanging a flexible formwork above a preset position of the bottom plate 2 of the mining face tunnel 1, a second steel mesh cage is pre-installed in the flexible formwork, and concrete is poured into the flexible formwork to form a supporting wall 4.

[0040] Specifically, before pouring, clean the bottom plate 2 of the mining face tunnel 1, hang the flexible formwork at the designed position, unfold and shape it, and place the second steel mesh cage in the flexible formwork. Then install the concrete grouting pipe and the orifice hose, start the concrete pump to pump and pour the wall and the π-shaped steel beam 6. In this embodiment, the support wall 4 adopts a concrete flexible formwork wall, and the thickness of the support wall 4 is 1m-2m. The support wall 4 is set in the mining face tunnel 1 to effectively cut off the rotation of the direct top, stabilize the overburden rock contact with the gangue, and reduce the tunnel pressure.

[0041] Furthermore, the method for controlling surrounding rock of deep soft rock gob-side tunnel also includes: opening a second groove at a preset position of the base plate 2, pouring concrete into the second groove, and after the concrete solidifies, pouring a formed support wall 4 into the flexible formwork until the support wall 4 abuts against the π-shaped steel beam 6, so as to improve the bearing capacity of the support wall 4 and avoid the support wall 4 being placed on the soft rock base plate 2, causing the support wall 4 to become unstable.

[0042] Optionally, in an embodiment of the present invention, the concrete is C40 concrete.

[0043] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for controlling surrounding rock of gob-side entry retaining in deep soft rock, characterized in that: include: After the working face is mined for a preset distance, a π-shaped steel beam is set on the top plate of the mining working face tunnel, a supporting wall is cast on one side of the mining working face tunnel, and the top of the supporting wall is abutted against the π-shaped steel beam; Components are laid along the center line of the mining face tunnel, and a plurality of supporting piers are cast along the extension direction of the length of the components, and the tops of the supporting piers are made to abut against the π-shaped steel beams.

2. The surrounding rock control method for deep soft rock gob-side entry retaining according to claim 1 is characterized in that: The step of laying components along the center line of the mining face roadway further includes: A first groove is opened on the bottom plate of the mining face tunnel along the center line of the mining face tunnel, the component is buried in the first groove, and the first groove is filled with concrete.

3. The surrounding rock control method for deep soft rock gob-side entry retaining according to claim 2 is characterized in that: The step of opening a first groove on the bottom plate of the mining face tunnel along the center line of the mining face tunnel and burying the component in the first groove further comprises: A plurality of pairs of I-beams are arranged along the extension direction of the length of the first groove, and the plurality of pairs of I-beams are spliced ​​or overlapped in sequence.

4. The surrounding rock control method for deep soft rock gob-side entry retaining according to claim 3 is characterized in that: A plurality of pairs of I-beams are arranged along the extension direction of the length of the first groove, and the step of overlapping the plurality of pairs of I-beams in sequence further comprises: Arrange some pairs of I-beams in parallel among the multiple pairs of I-beams, and arrange the remaining pairs of I-beams close together, and the I-beams arranged in parallel and the I-beams arranged close together are arranged alternately; The two ends of the I-beams arranged close together are inserted into the I-beams arranged in parallel.

5. The surrounding rock control method for deep soft rock gob-side entry retaining according to claim 3 is characterized in that: Also includes: Before laying a plurality of pairs of I-beams in the first groove, casting the first groove once; After the first groove is filled with the I-beam, the first groove is poured a second time until the first groove is filled.

6. The surrounding rock control method for deep soft rock gob-side entry retaining according to claim 3 is characterized in that: The step of casting a plurality of supporting piers along the extension direction of the length of the component further comprises: Casting the supporting piers at the joints or overlaps of two adjacent pairs of I-beams; After a plurality of pairs of I-beams are spliced ​​or overlapped into an integral frame, the supporting piers are cast at both ends of the integral frame, wherein the diameter of the supporting piers is greater than the distance between a pair of parallel I-beams.

7. The surrounding rock control method for deep soft rock gob-side entry retaining according to claim 6 is characterized in that: The steps for pouring the supporting piers include: After the first groove is fully poured and solidified, a plurality of restraining sleeves are arranged on the first groove along the extension direction of the length of the first groove, and a first steel mesh cage is pre-installed in the restraining sleeves; Concrete is poured into the restraining sleeve to form the supporting pier.

8. The surrounding rock control method for deep soft rock gob-side entry retaining according to claim 7 is characterized in that: Also includes: A plurality of pairs of tension anchor rods are arranged along the extension direction of the length of each supporting pier column.

9. The surrounding rock control method for deep soft rock gob-side entry retaining according to claim 1, characterized in that: The steps of pouring the supporting wall on one side of the mining face tunnel include: A flexible formwork is hung at a preset position on the roof of the mining face tunnel, wherein a second steel mesh cage is preset in the flexible formwork; Concrete is poured into the flexible formwork to form the supporting wall.

10. The surrounding rock control method for deep soft rock gob-side entry retaining according to claim 9, characterized in that: Also includes: A second groove is opened at a preset position of the bottom plate and concrete is poured, and after the concrete solidifies, the supporting wall is poured on the second groove.

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