CN112065394B

CN112065394B - Roof cutting and roadway retaining cooperative anchoring and protecting structure and construction method thereof

Info

Publication number: CN112065394B
Application number: CN202010954427.0A
Authority: CN
Inventors: 龙景奎; 刘碧雁; 吴家来; 曹佐勇; 乞朝欣; 郭厚亮; 兰红; 纪少思; 徐再刚; 谢晶; 肖国强; 冯会杰; 梁勇生; 赵春
Original assignee: China University of Mining and Technology CUMT
Current assignee: China University of Mining and Technology CUMT
Priority date: 2020-09-11
Filing date: 2020-09-11
Publication date: 2021-10-08
Anticipated expiration: 2040-09-11
Also published as: CN112065394A

Abstract

The invention discloses a roof cutting and roadway retaining cooperative anchoring and protecting structure and a construction method thereof, belongs to the technical field of roadway tunneling and supporting, and solves the problems that the existing roadway retaining structure is poor in stability and adaptability, large in deformation, high in control cost, easy to cause roof accidents, low in applicability of the existing roadway retaining technology and the like. The construction method of the invention comprises the following steps: directional blasting pre-splitting is carried out between the direct top plate and the working face top plate in the roadway, and the mechanical connection between the direct top plate and the working face top plate is cut off; constructing a roof-cutting and roadway-retaining cooperative anchoring structure consisting of an in-roadway cooperative anchoring structure and a roadside cooperative supporting structure on a direct roof in the roadway and a roof adjacent to a working face after blasting pre-splitting; and (4) synchronously building a retained roadway closed structure at the outer side of the waste rock blocking support body to finish the construction of the roof cutting retained roadway and the anchor protection structure. The invention has simple and easy construction and low anchoring and protecting cost, solves the control problems of stability, adaptability and applicability of the gob-side entry retaining structure of the coal mine, and has higher application and popularization values.

Description

Roof cutting and roadway retaining cooperative anchoring and protecting structure and construction method thereof

Technical Field

The invention relates to the technical field of roadway tunneling and supporting, in particular to a roof cutting and roadway retaining cooperative anchoring and protecting structure and a construction method thereof.

Background

For a long time, the coal mine in China mainly adopts a coal pillar remaining mining method, so that the loss of the mined coal accounts for about 40 percent of the total loss of the whole mine coal. And the gob-side entry retaining mode is adopted for mining, so that the mining rate of a mining area can be improved by 10-20%, the tunneling rate of a roadway is reduced by 25-30%, the problems of gas control, mining disorder and the like are effectively solved, the economic benefit and the technical advantage are obvious, and the requirements of safe, economic, efficient, green and sustainable mining are better met.

And the key for determining the roadway retaining effect and popularizing and applying is to improve the stability and adaptability of the roadway retaining anchoring structure. In the past, the control of the entry retaining structure is performed under the destructive effect of 'passively' accepting the movement of the overlying strata, and the research on the structural adaptability is less involved, so that the application and popularization of the gob-side entry retaining technology are influenced.

Therefore, it is urgently needed to provide a roof cutting and entry retaining cooperative anchoring structure capable of remarkably enhancing the stability and the adaptability of a gob-side entry retaining structure and a construction method thereof.

Disclosure of Invention

In view of the above analysis, the present invention aims to provide a roof cutting and roadway retaining cooperative anchoring structure and a construction method thereof, so as to solve the major problems of poor stability and adaptability, large deformation, high control cost, easy occurrence of roof accidents, and poor applicability of the existing roadway retaining technology.

The purpose of the invention is mainly realized by the following technical scheme:

on one hand, the construction method of the roof cutting and roadway retaining cooperative anchoring and protecting structure is provided, and comprises the following steps:

step S1: directional blasting pre-splitting is carried out between the direct top plate and the working face top plate in the roadway, and the mechanical connection between the direct top plate and the working face top plate is cut off;

step S2: constructing a roof-cutting and roadway-retaining anchoring structure consisting of an in-roadway cooperative anchoring structure and a roadside cooperative supporting structure on the roof directly in the roadway and the roof adjacent to the gob after blasting pre-splitting;

and step S3, after the construction of the waste rock blocking support body is completed, a roadway-retaining closed structure is synchronously built on the outer side of the waste rock blocking support body, and the construction of the roof-cutting roadway-retaining and anchor-protecting structure is completed.

Further, the step S1 includes the following steps:

step S11: after the stope face is formed, drilling a plurality of groups of blast holes on the roof in the roadway close to the stope face from inside to outside along the direction of the roadway;

step S12: after the same group of blast holes are drilled, selecting the number of the segmented charging structures, the number of the energy-collecting pipes and the explosive quantity according to the surrounding rock structure, the mechanical property and the depth condition of the blast holes, and respectively charging the required explosive quantity and the detonators into the corresponding energy-collecting pipes;

step S13: sequentially feeding the assembled energy-gathering pipes into the blast holes, and plugging the blast holes; directional blasting pre-splitting is carried out through the energy-gathering pipe, and the mechanical connection between the direct top plate and the working face top plate is cut off.

Further, in step S11, the blastholes are drilled and blasted in groups, and the number of the blastholes in the same group is 8-10; the drilling positions of the same group of blasting holes are on the same straight line, and the drilling angles are kept unchanged, so that the angles of the same group of blasting holes are kept parallel.

Further, the diameter of the blast hole is 50mm, the angle is 15-20 degrees, the depth is 6500-8000mm, and the distance between the two holes is 500-700 mm.

Further, in step S12, each charge structure corresponds to one energy collecting tube, each energy collecting tube has a length of 1500mm and a diameter of 42 mm; each blast hole is filled with 3-4 energy-gathering pipes.

Furthermore, the depth of the blast hole is 6500mm, and 3 energy-gathering pipes are used; the first energy-collecting pipe is filled with 3 sections of explosives, the second energy-collecting pipe is filled with 2 sections of explosives, and the third energy-collecting pipe is filled with 1 section of explosives.

Furthermore, the third energy-collecting pipe is filled into 2-3 water-saving sand bags, and the water-saving sand bags are sequentially filled upwards from the lower pipe orifice.

Further, in step S13, a plurality of sections of stemming are used to plug the blasthole;

the plugging length of the stemming is 2000mm, the length of each section of the stemming is 200mm and 300mm, and each section of the stemming is fed in and is tamped by a gun and a stick.

Further, step S1 further includes:

step S14: carrying out blasting pre-splitting effect detection at intervals of 30-50 m;

selecting 2-3 adjacent blastholes from the same group of blastholes as detection blastholes, and adopting a detachable blasthole plugging device to replace stemming for plugging; and (5) detaching the blast hole plugging device after blasting, and detecting the blasting effect.

Further, step S2 includes the following steps:

step S21: when a roadway is tunneled and before working face extraction, an anchor rod, an anchor cable I and an anchor cable II are used for building an in-roadway cooperative anchoring structure; the in-lane cooperative anchoring structure consists of three secondary substructures, namely a top plate anchoring beam, a roadside reinforcing beam and a coal side anchoring body;

step S22: when the working face passes the stoping, constructing a roadside cooperative supporting structure at the stoping side of the entry retaining section; the roadside cooperative supporting structure consists of three secondary substructures of a waste rock retaining support body, a top cutting support body and a waste rock support body.

Further, step S21 includes the following steps:

step S211: during roadway excavation, cooperatively anchoring surrounding rocks of the top plate through the anchor rods, the anchor cables I, the anchor nets and the steel belts to build a top plate anchoring beam;

step S212: before stoping of the working face, the top plate anchoring beam and the deep stable rock mass of the top plate are anchored into a whole through the anchor cable II and the steel belt, and a roadside reinforcing beam is built;

step S213: and during roadway excavation, the solid coal side is cooperatively anchored through the anchor rods, the anchor cables III, the anchor nets and the steel belts, and a coal side anchoring body is built.

And further, drilling and installing an anchor cable III and an anchor cable II before stoping on a working face.

Further, step S22 includes the following steps:

step S221: after the stoping of the working face passes, a waste rock blocking support body is built by adopting an I-shaped steel beam and a connecting rod and is used for blocking waste rocks collapsed in the goaf;

step S222: the roof-cutting support is built by adopting single columns, hinged beams, iron shoes 26 and connecting devices, and is used for reinforcing and supporting a roof anchoring beam and a roadside reinforcing beam;

step S223: according to the surrounding rock structure and performance of the coal seam roof, the goaf roof is fully collapsed and the goaf is filled based on reasonable blasting roof cutting design, so that a waste rock support body is formed and the stable rock mass on the goaf is effectively supported.

Further, in step S221, the i-beam is erected at the junction of the goaf roof and the roof in the roadway, and the distance between the i-beam and the anchor rod closest to the goaf side roof is 200 mm.

Further, in the step S222, the hinged beam is arranged along the roadway direction, is attached to the roof bolt tray close to the outermost roof of the gob, and is supported by the single column.

Further, step S3 includes the following steps:

step S31: paving a reinforcing mesh, sealing cloth, a wire gauze and a sand bag in sequence from the roadside to the gob direction, and forming a roadway-retaining sealing structure on the outer side of the waste rock retaining support body;

step S32: connecting a wire netting, a sealing cloth, a reinforcing mesh and a top plate anchor net in sequence on the outer side of an I-shaped steel beam for erecting gangue blocking support;

step S33: after the connection construction of the reinforcing mesh, the closed cloth, the wire netting and the top plate anchor net is completed, the sand bag is tightly piled outside the wire netting.

Furthermore, in step S32, the overlapping position of the wire mesh, the sealing cloth, the reinforcing mesh and the top plate anchor mesh is not less than 100mm, and the overlapping position is bound by wire.

On the other hand, the roof-cutting entry-retaining cooperative anchoring structure is built by the building method, and the formed roof-cutting entry-retaining cooperative anchoring structure consists of two substructures, namely an in-lane cooperative anchoring structure and a roadside cooperative supporting structure;

the in-lane cooperative anchoring structure consists of three secondary substructures, namely a top plate anchoring beam, a roadside reinforcing beam and a coal side anchoring body;

the roadside cooperative supporting structure consists of three secondary substructures of a waste rock retaining support body, a top cutting support body and a waste rock support body.

Compared with the prior art, the invention has at least one of the following beneficial effects:

a) the invention provides a construction method of a roof-cutting roadway-retaining collaborative anchoring structure, which adopts a directional blasting presplitting roof-cutting method, fully considers the influence range (within 30 m) and the pressure effect of advanced dynamic pressure generated during stoping of a working face, and proposes that the position of blasting presplitting roof-cutting needs to exceed the stoping position of the working face by 30-50m, so that the roof plate of the working face which is separated from the roof plate in the roadway is more effectively sunk, fractured and crushed by virtue of the acting force of the advanced dynamic pressure, the roof plate is more fully collapsed after the stoping of the working face is passed, on one hand, the roof plate which is not collapsed above is more effectively supported, and on the other hand, the influence and the damage to the roof plate in the roadway are obviously reduced.

b) The construction method of the roof-cutting and roadway-retaining cooperative anchoring structure is based on a cooperative anchoring principle, and is characterized in that two substructures of an in-roadway cooperative anchoring structure and a roadside cooperative supporting structure and six secondary substructures contained by the two substructures are constructed, so that the structure is simple, the layers are clear, the cooperative anchoring and protecting effect is exerted between each substructure and the secondary substructures, the stability and the adaptability of the roof-cutting and roadway-retaining cooperative anchoring structure are obviously improved, and the safety, the reliability and the applicability of the structure are improved.

c) According to the construction method of the roof-cutting entry-retaining cooperative anchoring structure, provided by the invention, a cooperative anchoring principle and method are applied to gob-side entry-retaining structure control, and the stress state of the entry-retaining surrounding rock is further improved through roof-cutting pressure relief, intra-lane cooperative anchoring and roadside cooperative supporting, so that the stability and the adaptability of the entry-retaining structure are obviously improved, the entry-retaining cost is obviously reduced, the method is one of important directions of gob-side entry-retaining theoretical development and technical attack, and has a wide application prospect.

d) According to the construction method of the roof-cutting and roadway-retaining cooperative anchoring structure, on one hand, the in-roadway cooperative anchoring structure is constructed through the cooperative anchoring effect of the roof plate anchoring beam, the roadside reinforcing beam and the coal side anchoring body, and on the other hand, the roadside cooperative supporting structure is constructed through the cooperative supporting effect of the waste rock retaining support body, the roof-cutting support body and the waste rock support body; on the other hand, the stability and the adaptability of the cut-top entry retaining anchoring structure are obviously enhanced by exerting the cooperative bearing and the cooperative deformation of the intra-lane cooperative anchoring structure and the roadside cooperative supporting structure, so that the problems and the problems existing in gob-side entry retaining are effectively solved, the engineering applicability of the cut-top entry retaining cooperative anchoring structure is enhanced, and the safe, economic, efficient and green production of a coal mine is promoted.

e) The construction method of the roof cutting entry retaining cooperative anchoring and protecting structure provided by the invention is simple and easy to construct, has low anchoring and protecting cost, solves the control problem of stability and adaptability of the gob-side entry retaining structure of the coal mine, provides theoretical, technical and method support for more coal mines to implement gob-side entry retaining mining, is suitable for controlling other engineering rocks, and has great application and popularization values.

In the invention, the technical schemes can be combined with each other to realize more preferable combination schemes. Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and drawings.

Drawings

The drawings are only for purposes of illustrating particular embodiments and are not to be construed as limiting the invention, wherein like reference numerals are used to designate like parts throughout.

FIG. 1 is a schematic diagram of a borehole drilling and sealing structure in an embodiment of the present invention;

FIG. 2 is a schematic diagram of a roof cutting and roadway retaining cooperative anchoring structure in the embodiment of the present invention;

FIG. 3 is a schematic view of cooperative control of a roof cutting and roadway retaining anchoring structure in the embodiment of the present invention;

FIG. 4 is a schematic structural diagram of a water sand bag in an embodiment of the invention;

FIG. 5a is a schematic structural diagram of a borehole damper in an embodiment of the present invention;

FIG. 5b is a first schematic structural diagram of a damping rod according to an embodiment of the present invention;

FIG. 5c is a schematic structural diagram of a damping rod according to an embodiment of the present invention;

FIG. 5d is a first schematic structural diagram of a damping cap according to an embodiment of the present invention;

FIG. 5e is a schematic structural diagram of a damping cap according to an embodiment of the present invention;

FIG. 6a is a schematic cross-sectional view of a hole packer in an embodiment of the invention;

FIG. 6b is a schematic plan view of a hole packer in accordance with an embodiment of the present invention;

FIG. 7 is a schematic structural diagram of a blasthole plugging device in an embodiment of the invention;

FIG. 8 is a schematic diagram of the shot distance and the detected position in the embodiment of the present invention;

fig. 9 is a diagram showing the pre-splitting effect of blasthole blasting in the embodiment of the invention.

Reference numerals:

1-blast hole; 2-energy gathering pipe; 3-an explosive; 4-a detonator; 5-water sand bag; 501-external packing bag; 502-fine sand; 503-water; 6-a blasthole plugging device; 601-a damping rod; 602-a damping cap; 603

A wire hole; 604-a borehole damper; 605-column of air; 606-damping cushion blocks; 607-hole sealing disk; 608-blast hole packer; 609-a monomer column; 610-blasted area; 611-unexploded region; 7-A detonating cord; 8-a top plate; 9-mining the side coal slope; 10-solid coal side; 11-cooperative anchoring structures in the lane; 12-roadside cooperative support structures; 13-roof anchoring beam; 14-roadside reinforcing beams; 15-coal upper anchoring body; 16-a waste rock retaining support body; 17-a topping support; 18-a gangue supporting body; 19-anchor rod; 20-anchor cable one; 21-anchor cable two; 22-anchor cable III; 23-steel i-beams; 24-a monomer column; 25-articulated beam; 26-iron shoe.

Detailed Description

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate preferred embodiments of the invention and together with the description, serve to explain the principles of the invention and not to limit the scope of the invention.

Example 1

The invention discloses a roof cutting and roadway retaining cooperative anchoring structure capable of obviously enhancing stability and adaptability and a construction method thereof, wherein the roof cutting and roadway retaining cooperative anchoring structure comprises the following steps:

step S1: by researching the tunnel-retained top plate presplitting blasting roof cutting principle, in order to reduce the damage degree of the goaf top plate caving to the top plate in the tunnel during stoping of the working face, directional blasting presplitting is firstly carried out between the direct top plate in the tunnel and the working face top plate, the mechanical relation between the direct top plate and the working face top plate is cut off, and the damage of the goaf top plate caving to the top plate in the tunnel after stoping is reduced. The blasting pre-splitting between the direct roof and the working face roof in the roadway comprises the following steps:

step S11: before stoping of a working face, drilling blastholes 1 from inside to outside along the direction of a roadway, wherein the blastholes 1 are drilled and blasted in groups at the position, 200mm close to a stope side, of a top plate in the roadway, the blastholes 1 in the same group are preferably drilled and blasted, and 8-10 blasting blastholes 1 in the same group are preferably circularly drilled.

Further, the blastholes 1 are arranged on the top plate 8 close to the goaf side 9, the distance between the blastholes 1 and the goaf side 9 is 200mm, the drilling positions of the same group of blasting blastholes 1 are on the same straight line according to the trend of the roadway, the drilling installation angle is kept unchanged, and the angles of the same group of blastholes 1 are kept parallel.

Further, the diameter of the blasthole 1 is 50mm, the angle (tangent line) of the blasthole 1 is 15-20 degrees, the depth of the blasthole 1 is 6500-8000mm, the distance between the blastholes is 500-700mm, and the angle of the blasthole 1 and the position of the drilled hole are shown in fig. 1. The position of the top cutting blasting is required to exceed the influence range (outside the range of 30-50 m) of a leading pressure area formed by the stoping of a working face, and specific blasting parameters are determined according to the structure, the performance and the like of surrounding rocks of the top plate.

Step S12: after the same group of blast holes 1 are drilled, selecting the number of the segmented charging structures, the number of the energy-collecting pipes and the charging amount according to the surrounding rock structure, the mechanical property and the depth of the blast holes; according to the explosive loading of each section, the required explosive and the detonator 4 are respectively loaded into the corresponding energy-gathering pipes.

Furthermore, each charge structure is realized by adopting an energy-collecting pipe 2, and each energy-collecting pipe 2 is 1500mm long and 42mm in diameter; each blasthole 1 is filled with 3-4 energy-gathering pipes 2, namely the total length of the sectional charging structure is 4500-.

Illustratively, when the depth of a blast hole is 6500mm, 3 energy-collecting pipes 2 are used, and a 3-2-1 segmented charging structure and charging amount are adopted, as shown in fig. 1, namely, a first energy-collecting pipe is filled with 3 sections of explosives 3, a second energy-collecting pipe is filled with 2 sections of explosives 3, a third energy-collecting pipe is filled with 1 section of explosives 3, and the like; during charging, the explosive is continuously loaded downwards from the upper end pipe orifice of the energy collecting pipe 2, and the explosive 3 at the lowest part is fixed, so that the explosive is prevented from sliding out when the energy collecting pipe 2 is installed.

In order to reduce the huge impact force formed by the explosive 3 after being detonated along the axial direction of the blasthole, the last energy-collecting pipe 2 (such as the third pipe) is filled with 2-3 water-saving sandbags 5, the sandbags 5 are sequentially filled upwards from the pipe orifice at the lower end, the sandbag 5 at the lowest part is fixed to prevent the sandbags 5 from sliding out during installation, and a certain air column is required to be reserved between the sandbags 5 and the explosive 3.

Furthermore, the diameter of the water sand bag 5 is 40mm, the length of each section is 350mm, the thickness of the bag film is not less than 1mm, sand with the height of 250mm is filled into the bag, then the bag is filled with water, and then the bag is sealed.

Step S13: sequentially feeding the energy-collecting pipes 2 filled with the explosive 3 and the sand bags 5 into the blasthole 1, and plugging the blasthole 1 by adopting a plurality of sections of stemming to prevent the explosion energy from directly rushing out along the axial direction of the blasthole 1; and performing directional blasting pre-splitting after the blasthole 1 is plugged so as to cut off the mechanical connection between the direct top plate and the working face top plate.

Furthermore, the stemming plugging length is about 2000mm, each section of stemming is 200mm and 300mm, each section of stemming needs to be tamped by a stemming rod when being sent into the section of stemming, and the stemming can not be completely flushed out after blasting.

Step S14: and (5) detecting the blasting effect.

In order to detect the blasting pre-splitting effect, the blasting pre-splitting effect is detected once at intervals of 30-50m, namely 2-3 adjacent blastholes 1 are selected from the same group of blasting blastholes 1, the detection blastholes 1 are sealed by adopting a detachable blasthole plugging device 6 instead of stemming, the blasthole plugging device 6 can prevent the explosion energy from axially rushing out along the blastholes, and the blasthole plugging device 6 is convenient to take out for detecting the blasting effect after blasting.

It is to be understood that, in step S13, the detection blasthole 1 may be sealed by the blasthole sealing device 6 instead of the stemming.

Step S2: through research and analysis on the principle of cooperative control of the entry retaining anchor structure, a roof-cutting entry retaining anchor structure consisting of an in-lane cooperative anchoring structure 11 and a roadside cooperative support structure 12 is built on a direct roof in a lane and a roof adjacent to a gob after blasting pre-splitting, and as shown in fig. 1 to 3, the method specifically comprises the following building steps:

step S21: when a roadway is tunneled and before stoping of a working face, the in-roadway cooperative anchoring structure 11 is built by using anchoring materials such as the anchor rod 19, the anchor cable I20 and the anchor cable II 21, and the in-roadway cooperative anchoring structure 11 is composed of three secondary substructures including a top plate anchoring beam 13, a roadside reinforcing beam 14 and a coal side anchoring body 15.

In this embodiment, the roof anchoring beam 13 plays an effective supporting role for the upper-tracked rock mass, the roadside reinforcing beam 14 reinforces the roof anchoring beam 13 and the upper-tracked stable rock mass into a whole, and the coal slope anchoring body 15 plays an effective supporting role for both the roof anchoring beam 13 and the roadside reinforcing beam 14. The roof anchoring beam 13 and the coal side anchoring body 15 are built during roadway excavation, and the roadside reinforcing beam 14 can be built at a certain distance from the working face in the later stage.

Step S211: when a roadway is tunneled, roof surrounding rocks in a certain range are cooperatively anchored through an anchor rod 19, an anchor cable I20, an anchor net, a steel belt and the like, and a roof anchoring beam 13 is built, wherein the specific construction method comprises the following steps:

determining the length of the anchor rod 19 according to the specific conditions of roadway height, surrounding rock loosening ring and the like, wherein the length of the anchor rod 19 is 2400-2600mm, the anchoring length is 1000mm, and the pretightening force is 120 kN; the included angle between the anchor rod 19 of the top plate close to the shoulder angle and the vertical line is 20 degrees, the drilling and the installation are deviated to the coal slope direction, and other anchor rods 19 are perpendicular to the contour line of the roadway and the drilling and the installation are carried out. Further, the row spacing of the anchor rods 19 is preferably 800mm, and the spacing and the installation number are determined according to actual conditions.

Specifically selecting the length of the anchor cable I20 according to the structure of surrounding rocks, the mechanical property and the like, wherein the length of the anchor cable I20 is 6200-7200mm, the anchoring length is 2000mm, and the pretightening force is 180 kN; the included angle between the anchor cable I20 close to the two shoulder angles and the vertical line is 20 degrees, the anchor cables are drilled and installed in the direction deviated from the coal side, and the other anchor cables I20 are drilled and installed vertically. Furthermore, the first 20 rows of anchor cables are 1600mm in distance, and the distance and the installation number are determined according to actual conditions.

The anchor rods 19 are transversely interlocked by adopting W-shaped steel belts along the section of the roadway, the anchor cables I20 are longitudinally and continuously interlocked by adopting T-shaped steel belts along the direction of the roadway, and the specifications of the W-shaped steel belts and the T-shaped steel belts are selected according to the row spacing between the anchor rods 19 and the anchor cables I20; the anchor net can adopt a steel bar net or a rhombic steel wire net, and can be selected according to actual conditions.

Step S212: before stoping of the working face, the top plate anchoring beam 13 and the stable rock mass in the deep part of the top plate are anchored into a whole through the anchor cable II 21 and the steel belt, and the roadside reinforcing beam 14 is built. Wherein, anchor line three 22 can be drilled with anchor line two 21 before the working face is recovered. The specific construction method comprises the following steps:

the length of the second anchor cable 21 is specifically selected according to the structure of surrounding rocks, the mechanical property and the like, illustratively, the length of the second anchor cable 21 is 8200-9200mm, which is 2000mm longer than that of the first anchor cable 20, the length of the second anchor cable is not less than 1000mm when the second anchor cable is anchored into a more stable rock stratum above the first anchor cable, the anchoring length is 2500mm, and the pretightening force is 200 kN; the anchor cables 21 are vertically drilled and installed, the row spacing is 1600mm, the spacing and the installation number are determined according to actual conditions, and the distance between the outermost anchor cable 21 and the goaf side is 800-1000 mm.

And the anchor cables II 21 are longitudinally and continuously linked by adopting T-shaped steel belts along the trend of the roadway.

In order to reduce the weakening of the anchoring force of the anchor cable II 21 and the possible loosening and damage caused by blasting and top cutting, the anchor cable II 21 is preferably drilled beyond the working face by 30-50m and after the blasting and top cutting is finished.

Step S213: when a roadway is tunneled, the solid coal side 10 in a certain range is cooperatively anchored through the anchor rods 19, the anchor cables three 22, the anchor net, the steel belt and the like, and the coal side anchoring body 15 is built, wherein the specific construction method comprises the following steps:

the length and anchoring parameters of the anchor rod 19 are the same as those of the roof anchor rod 19, and the pretightening force is 100 kN; the included angle between the anchor rod 19 at the upper corner of the upper part and the horizontal line is 15 degrees, and the drill mounting is deviated to the direction of the top plate; the included angle between the upper lower angle anchor rod 19 and the horizontal line is 30 degrees, and the drilling and installation are performed in the direction deviated from the bottom plate; the other anchor rods 19 are drilled perpendicular to the roadway contour. The row spacing of the anchor rods 19 is preferably 800mm, and the spacing and the installation number are determined according to actual conditions.

Selecting the length of the anchor cable III 22 according to the conditions of a coal side loosening ring, a top-bottom plate rock stratum and the like, wherein the length of the anchor cable III 22 is 4200-6200mm, the anchoring length is 1500mm, and the pre-tightening force is 140 kN; an included angle between an anchor cable III 22 on the upper corner of the side part and the horizontal line is 20 degrees, and the anchor cable III is drilled and installed in a direction deviated to the top plate; an included angle between the anchor cable III 22 at the lower corner of the side part and the horizontal line is 20 degrees, and the anchor cable II is drilled and installed in a direction deviated from the bottom plate; the row spacing of the anchor cables three 22 is preferably 1600mm, and the spacing is determined according to actual conditions. When the coal seam is firmer, a row of anchor cables three 22 can be drilled and arranged at the waist line and perpendicular to the coal side.

The anchor rods 19 are transversely interlocked along the section of the roadway by adopting a W-shaped steel belt; and (3) longitudinally and continuously interlocking the anchor cables III 22 by using T-shaped steel belts along the roadway direction (the W-shaped steel belts are preferably used when a row of the anchor cables III 22 is drilled on the coal side waist line).

In order to reduce the weakening phenomenon of the anchoring force of the anchor cable three 22 and the loosening and damage possibly caused by blasting and roof cutting, the anchor cable three 22 and the anchor cable two 21 are preferably constructed synchronously.

Step S22: after the stoping of the working face is passed, a roadside cooperative supporting structure 12 is built on the goaf side of the entry retaining section, the roadside cooperative supporting structure 12 is composed of three secondary substructures, namely a waste rock blocking support 16, a top cutting support 17 and a waste rock support 18, wherein the waste rock blocking support 16 is used for blocking waste rock caving in the goaf, the top cutting support 17 is used for reinforcing and supporting the top plate anchoring beam 13 and the roadside reinforcing beam 14, and the waste rock support 18 is used for effectively supporting relatively stable rock mass on the goaf. The roadside cooperative supporting structure 12 is built to realize effective supporting and control of a roadside roof and a gob deep roof, gob gangue is prevented from falling into a roadway, and a foundation is laid for roadside sealing construction. The construction method is specifically characterized by comprising the following steps:

step S221: the waste rock retaining support 16 is built by adopting materials such as I-shaped steel beams 23, connecting rods and the like so as to prevent waste rocks formed after the goaf roof collapses from entering a roadway, and the specific construction method comprises the following steps:

the I-shaped steel beam 23 for blocking the waste rock cannot be erected in a roadway, needs to be erected at the joint of a goaf caving roof and a roof in the roadway, and is spaced by 200mm from the anchor rod 19 closest to the goaf side roof.

Further, after the working face is mined, by utilizing an inverted step formed by the caving of a goaf top plate after blasting and roof cutting, firstly digging a pit on a bottom plate to embed the lower part of the I-shaped steel beam 23, wherein the embedding depth is required to be not less than 150mm, and then erecting the upper part of the I-shaped steel beam 23 on the inverted step, wherein the erecting length is not less than 100 mm; if the top plate does not form an effective inverted step, a pit with the depth not less than 100mm is planed at the joint of the goaf top plate and the roadway top plate, and then the upper part of the I-shaped steel beam 23 is inserted into the pit.

For convenience of construction, according to the height of a goaf side, a complete I-shaped steel beam 23 can be used, two sections of I-shaped steel beams can also be used, a connecting device is adopted in the middle for linkage, and the overlapping length is required to be not less than 1000 mm.

Further, adopt the connecting rod to interlock between the I-steel roof beam 23, prevent to topple over.

Step S222: the roof-cutting support body 17 is constructed by adopting materials such as a single column 24, a hinged beam 25, an iron shoe 26, a connecting device and the like, so that the reinforcing support of a roadside reinforcing beam and a roof anchoring beam is realized, and simultaneously, the roof of a goaf is more favorably collapsed, and the concrete construction method comprises the following steps:

the hinged beam 25 is arranged along the trend of the roadway and is attached to the anchor rod tray close to the outermost roof of the goaf, the hinged beam 25 is supported by the single column 24, the row spacing is 800-1000mm (selected according to the structural performance of the roof rock stratum, the specification of the hinged beam 25 and the like), and the initial supporting force of the single column 24 is 10-15MPa (selected according to the surrounding rock conditions of the roof and the action condition of the anchor rod and the anchor rope).

The lower portion of the monomer post 24 is fitted with a skate 26 to prevent the monomer post 24 from being pressed into the base plate. Further, the iron shoe 26 is made of a square steel plate of 300 × 300 × 20mm or a disc of 300 × 20 mm.

The monomer posts 24 are interlocked by connecting rods to prevent toppling.

Step S223: in order that the waste rock supporting body 18 can form effective support for the upper old roof after the goaf collapses, the reasonable blasting roof cutting design is based on the surrounding rock structure and the mechanical property of the coal seam roof, the joint cutting quality and effect are improved, the goaf roof is made to fully collapse and the goaf is filled, the waste rock supporting body 18 is formed and effectively supports the stable rock mass on the goaf, namely, the effective supporting effect is formed on the upper old roof, and the influence and damage of the subsequent fracture collapse of the old roof on the roof in the roadway are reduced. The waste rock supporting body 18 is composed of a waste rock pile formed after the top plate of the goaf collapses.

And step S3, after the construction of the waste rock retaining support body 16 is completed, immediately constructing a retained roadway closed structure outside the waste rock retaining support body, and finishing the construction of the roof cutting retained roadway and anchor protection structure by the system. The concrete construction process comprises the following steps:

step S31: and a reinforcing mesh, sealing cloth, a wire gauze and a sand bag are sequentially paved from the roadside to the goaf, and a roadway-retaining sealing structure is formed on the outer side of the waste rock retaining support 16.

Step S32: the entry retaining closed structure consists of a reinforcing mesh, closed cloth, a wire mesh and a sand bag. At the outer side of the I-shaped steel beam 23 for waste rock retaining support, an iron wire net, sealing cloth, a reinforcing mesh and a top plate anchor net are sequentially connected, and the overlapping part is required to be not less than 100mm and bound by iron wires.

Step S33: after the connection construction of the reinforcing mesh, the closed cloth, the wire netting and the top plate anchor net is completed, one or two layers of sandbags are piled up to be close to the outer side of the wire netting so as to enhance the tightness of the roadway retaining space, better realize gas control and prevent spontaneous combustion of the coal bed.

In the embodiment, the diameters of the first anchor cable 20, the second anchor cable 21 and the third anchor cable 22 are equal, illustratively, the diameter of the first anchor cable is 21.6mm, and the diameter of the anchor rod 19 is 22 mm; the resin anchoring agent is divided into a fast anchoring agent and a medium-speed anchoring agent, the anchor rod 19 can use the fast anchoring agent, and the anchor cables I20, II 21 and III 22 are matched by using the fast anchoring agent and the medium-speed anchoring agent; the setting time of the quick anchoring agent is about 60s, the setting time of the medium-speed anchoring agent is about 90s, the length of the anchoring agent is 500 mm/strip, and the diameter is preferably 25 mm.

The invention provides a cooperative anchoring and protecting structure and a construction method thereof aiming at stability and adaptability of a gob-side entry retaining structure, and the lane retaining anchoring and protecting structure is promoted to form a cooperative enhancement effect by the cooperative control design of an anchor rod 19, an anchor cable I20, an anchor cable II 21 and an anchor cable III 22 on the aspects of rod body length, pretightening force, anchoring length, drilling and loading angle and the like, and is specifically embodied in the following aspects:

(1) and the anchor rod 19, the anchor cable I20 and the anchor cable II 21 are used for realizing the cooperative anchoring of rock strata at different depths of the top plate. Specifically, the length of the anchor rod 19 is 2400-.

(2) The anchor rod 19 and the anchor cable three 22 are used for realizing the cooperative anchoring of the solid coal upper 10 at different depths. Specifically, the length of the anchor rod 19 is 2400-.

(3) And the coordination of the anchor rod 19, the anchor cable I20, the anchor cable II 21 and the anchor cable III 22 on the pretightening force is realized. Specifically, the pretightening force of the top plate anchor rod 19 is about 120kN, the pretightening force of the first anchor cable 20 is about 160kN, and the pretightening force of the second anchor cable 21 is about 200kN, so that the pretightening force cooperation of the top plate anchor rod 19, the first anchor cable 20 and the second anchor cable 21 is realized; the pre-tightening force of the side anchor rod 19 is about 100kN, and the pre-tightening force of the anchor cable III 22 is 140kN, so that the pre-tightening force cooperation of the solid coal side anchor rod 19 and the anchor cable III 22 is realized.

(4) The cooperation of the rod body length and the anchoring length of the anchor rod 19, the anchor cable I20, the anchor cable II 21 and the anchor cable III 22 is realized. Specifically, the length of the anchor rod 19 is 2400-2600mm, and the corresponding anchoring length is about 1000 mm; the length of the anchor cable I20 is 6200-7200mm, and the corresponding anchoring length is about 2000 mm; the length of the anchor cable II 21 is 8200 and 9200mm, and the corresponding anchoring length is about 2500 mm; the length of the anchor cable three 22 is 4200 and 5200mm, and the corresponding anchoring length is about 1500 mm. Different lengthening anchoring modes are selected for anchor rods and anchor cables with different lengths, and collaboration among the rod body length, the anchoring length and the pre-tightening force is achieved.

(5) The cooperation of the drilling angle and the structural design of the anchor rod 19, the anchor cable I20, the anchor cable II 21 and the anchor cable III 22 is realized. Specifically, the included angles between the anchor rods 19 of the top plate close to the shoulder angles of the two sides and the plumb line are both 20 degrees, the upward rolling angle of the anchor rod 19 at the uppermost end of the two sides is 15 degrees, the downward rolling angle of the anchor rod 19 at the lowermost end is 30 degrees, and the rest anchor rods 19 are arranged perpendicular to the contour line of the roadway; the included angle between the anchor cable I20 close to the shoulder angles on the two sides of the top plate and the plumb line is 20 degrees, and the other anchor cables I20 are vertically installed; the top plate is vertically installed close to the second mining side anchor cable 21; the included angle between the anchor cable three 22 at the upper corner of the solid coal side part and the horizontal line is 20 degrees, and the included angle between the anchor cable three 22 at the lower corner of the solid coal side part and the horizontal line is 20 degrees. Through the angle control to shoulder angle, base angle key position stock and anchor rope, can form effective "draw" effect to one side on the one hand, prevent that the country rock from warping and shifting out, on the other hand bores the dress through certain angle of base angle stock, anchor rope and effectively prevents and treats the pucking.

Compared with the prior art, the roof-cutting and roadway-retaining cooperative anchoring structure and the construction method thereof provided by the embodiment are based on the cooperative principle, on one hand, the in-roadway cooperative anchoring structure 11 is constructed through the cooperative anchoring effect of the roof plate anchoring beam 13, the roadside reinforcing beam 14 and the coal side anchoring body 15, and simultaneously, the roadside cooperative supporting structure 12 is constructed through the cooperative supporting effect of the waste rock retaining support body 16, the roof-cutting support body 17 and the waste rock support body 18; on the other hand, the cooperative bearing and the cooperative deformation of the in-lane cooperative anchoring structure 11 and the roadside cooperative supporting structure 12 are exerted, and the stability and the adaptability of the cut-top entry retaining anchoring structure are obviously enhanced, so that the problems and the problems existing in gob-side entry retaining are effectively solved, the engineering applicability of the cut-top entry retaining cooperative anchoring structure is enhanced, and the safe, economic, efficient and green production of a coal mine is promoted. The method is simple and easy to construct, has low anchoring and protecting cost, solves the limitations faced by the application and popularization of the coal mine gob-side entry retaining technology, is suitable for controlling other engineering rocks, and has great application and popularization values.

Example 2

The invention further discloses a top-cutting entry-retaining cooperative anchoring structure, which is built by adopting the building method of the embodiment 1, and consists of two substructures, namely an in-lane cooperative anchoring structure 11 and a roadside cooperative supporting structure 12; the in-lane cooperative anchoring structure 11 consists of three secondary substructures, namely a top plate anchoring beam 13, a roadside reinforcing beam 14 and a coal side anchoring body 15; the roadside cooperative supporting structure 12 consists of three secondary substructures, namely a waste rock retaining support 16, a roof cutting support 17 and a waste rock support 18.

Fig. 2 shows the spatial position relationship of the three secondary substructures of the roof anchoring beam 13, the roadside reinforcing beam 14 and the coal wall anchoring body 15 of the intra-roadway cooperative anchoring structure 11 and the three secondary substructures of the waste rock retaining support 16, the top cutting support 17 and the waste rock support 18 of the roadside cooperative supporting structure 12. By researching the space-time relationship and the synergistic effect between each substructure and the secondary substructure, a mechanical formula of the roof-cutting roadway-retaining cooperative anchoring structure is established, wherein the formula is (1) and (2), the mechanical formula is used as a theoretical basis and a judgment basis for stability and adaptability control of the roof-cutting roadway-retaining anchoring structure, and when the mechanical parameters of the anchoring structure meet the formula (1) and the formula (2), the constructed roof-cutting roadway-retaining anchoring structure is safe and reliable.

f(Fq₁+Fq₂+Fq₃+Fq₄+Fq₅+Fq₆)－∑(Fq₁+Fq₂+Fq₃+Fq₄+Fq₅+Fq₆)＝△F＞0 (1)

f(Fq₁+Fq₂+Fq₃+Fq₄+Fq₅+Fq₆)≥k·Fq₀ (2)

In the formula: fq₀For overburden forces, Fq₁For anchoring the beam-carrying capacity of the roof, Fq₂For anchoring the supporting force of the coal side, Fq₃For roadside reinforcing beam bearing capacity, Fq₄For roof-cutting support, Fq₅For retaining the supporting force of the waste rock, Fq₆The supporting force of the gangue body is adopted, the Delta F is the synergistic effect reinforcement, F represents the nonlinear synergistic effect among all the forces, sigma represents the linear superposition among all the forces, and k represents the safety coefficient of the roof cutting and roadway retaining anchoring structure.

Through verification, the mechanical parameters of the cut-top entry retaining anchoring structure constructed by the construction method of the embodiment conform to the formulas (1) and (2), so that the cut-top entry retaining anchoring structure constructed by the construction method of the embodiment is safe and reliable.

Example 3

The directional blasting presplitting roof cutting effect is one of key factors for determining gob-side entry retaining effect, and a reasonable blasting position and blasting parameter design is needed to promote good through cracks to be formed between adjacent blastholes, so that the influence and the damage degree of a roof in a roadway when the roof in a goaf collapses are obviously reduced, and meanwhile, the roof in the goaf collapses sufficiently, and the stability, the adaptability and the applicability of the gob-side entry retaining anchor protection structure are obviously enhanced. A specific embodiment of the present invention discloses a blasthole plugging device in step S14 in embodiment 1, which is capable of detachably plugging a blasthole 1, and is convenient for detecting a pre-splitting blasting roof cutting effect, as shown in fig. 4 to 9, the blasthole plugging device includes an inner blasthole damping device and an outer blasthole damping device, the inner blasthole damping device is detachably mounted in the blasthole, and includes a water sand bag 5 and a blasthole damper 604, and is used for damping and pressure relief of blast energy rushing out along the axial direction of the blasthole 1; the damping device outside the blasthole can be detached and arranged outside the blasthole and comprises a blasthole packer 608 and a monomer column 609 for preventing the explosion energy and the damping device inside the blasthole from rushing out of the blasthole.

In this embodiment, the water sand bag 5 includes an outer packing bag 501, fine sand 502 and water 503. A column of air 605 is left between the water sand bag 5 and the explosive 3. The synergistic effect of the water sand bag 5, the air column 605 and the blast hole damper 604 realizes the primary damping and pressure relief effect when the explosion energy rushes out along the axial direction of the blast hole 1.

In the present embodiment, the blasthole damper 604 comprises a damping rod 601 and a damping cap 602, wherein the damping cap 602 is provided with a wire hole 603. When the blasthole is plugged, a traction wire is firstly threaded through the wire leading hole 603, the wire end is required to be left outside the blasthole opening, and then the damping cap 602 and the damping rod 601 are sleeved and fastened and then are installed in the blasthole 1. Through the synergistic action among the damping rod 601, the damping cap 602 and the blasthole packer 608, the secondary damping and pressure relief effects on the blast energy during the axial punching of the blasthole 1 are realized.

In this embodiment, the blasthole packer 608 is composed of a damping pad 606 and a hole sealing disc 607. The damping cushion block 606 and the hole sealing disc 607 are assembled, then the assembled blast hole damper 604 is inserted into the blast hole 1, and then the blast hole packer 608 is used for sealing and the single column 609 is used for jacking. Three damping and pressure relief effects on the blast energy during the axial punching of the blasthole 1 are realized through the synergistic effect among the blasthole damper 604, the blasthole packer 608 and the monomer column 609.

In this embodiment, after the blasting is finished, on the basis of safety protection, the blasthole packer 608 and the monomer column 609 are removed, and then the blasthole damper 604 is moved out by using a pull wire, so as to realize field detection of the gob-side entry retaining presplitting blasting roof cutting effect.

The method for plugging the blasthole by using the blasthole plugging device in the embodiment comprises the following steps:

step S101: and manufacturing a water sand bag 5, and filling the water sand bag 5 into the energy-gathering pipe 2 at the lowest end of the blast hole 1 according to requirements to perform primary plugging on the blast hole 1. The water sand bag 5 filled in can realize the primary damping and pressure relief of the explosion energy.

The steps for manufacturing the single water sand bag 5 are as follows: fine sand 502 and water 503 are filled into the overwrap bag 501 and sealed. Preferably, the outer packaging bag 501 of the water sand bag 5 is made of a high-elasticity plastic film with the thickness not less than 1mm, the diameter of the outer packaging bag is 40mm, the length of the outer packaging bag is 350mm, and the volume ratio of the water 503 to the fine sand 502 is 1: 0.6; when the water sand bag 5 is manufactured, fine sand 502 with the height of 250mm is filled, then water 503 is filled, and finally the bag opening is clamped and sealed to prevent the water sand from seeping. The water sand bag structure is shown in figure 4.

Furthermore, the number of the sand bags 5 is selected according to the charge number of the energy collecting pipe 2 at the lowest end, and is 2-3 sections. Specifically, 2-3 water-saving sand bags 5 are arranged in the energy-collecting pipe 2 at the lowest end of the blasthole 1 from the bottom to the top and fixed to prevent slipping during installation, an air column 605 is left between the water sand bags 5 and the explosive 3, and the energy-collecting pipe 2 is blocked by a damper 604. The synergistic effect of the water sand bag 5, the air column 605 and the blast hole damper 604 realizes the primary damping and pressure relief effect when the explosion energy rushes out along the axial direction of the blast hole 1.

Step S102: and manufacturing a blast hole damper 604, and performing secondary plugging on the blast hole 1. The damping rod 601 and the damping cap 602 have the effect of 'rigidity and flexibility' to realize the secondary damping and pressure relief of the explosion energy.

The steps for making a single borehole damper 604 are: on the basis of processing the damping rod 601, the damping cap 602 and the wire leading hole 603, firstly threading a traction wire through the wire leading hole 603, requiring a wire end to be left outside an orifice of the blasthole 1 for moving the blasthole damper 604 out of the blasthole 1 after blasting; the damping cap 602 and the damping rod 601 are sleeved firmly, and the damping cap 602 and the damping rod 601 can be plugged by soft cloth or other materials to prevent slipping during installation; the borehole damper 604 is then loaded into the borehole. Through the synergistic action among the damping rod 601, the damping cap 602 and the blasthole packer 608, the secondary damping and pressure relief effects on the blast energy during the axial punching of the blasthole 1 are realized.

Furthermore, the damping rod 601 is made of high-elastic plastic, the damping rod 601 comprises a base and a rod body, the total length is 1800mm, the length of the base part is 300mm, the diameter of the base part is 46mm, the length of the rod body part is 1500mm, and the diameter of the rod body part is 40 mm; the damping cap 602 is made of alloy steel, and has an outer diameter of 46mm, an inner hole diameter of 42mm, an inner hole depth of 300mm, and a height of 500 mm. The structure of the blasthole damper 604 is shown in fig. 5 a-5 e.

Step S103: and manufacturing a blast hole packer 608, and installing the blast hole packer 608 to perform third plugging on the blast hole 1. The elastic damping function of the damping cushion block 606, the rigid impedance function of the hole sealing disc 607 and the elastic damping function between the damping rod 601 are exerted, so that the third damping and pressure relief of the explosion energy are realized.

The steps for making the hole packer 608 are: on the basis of manufacturing the damping cushion block 606 and the hole sealing disc 607, the damping cushion block 606 is firstly pressed into a circular groove of the hole sealing disc 607, then the central alignment blasthole 1 of the blasthole hole packer 608 is sealed, and the combined blasthole packer 608 is jacked to be solid by the monomer column 609. Three damping and pressure relief effects on the blast energy during the axial punching of the blasthole 1 are realized through the synergistic effect among the blasthole damper 604, the blasthole packer 608 and the monomer column 609.

Further, the damping pad 606 is made of high-elastic plastic and has the specification of

A disc, wherein the base of the damping rod 601 is in centered butt joint with the damping cushion block 606 during installation; the hole sealing plate 607 is made of alloy steel and has a specification of 160X 200mm, a circular groove is processed in the middle of the upper surface, and the specification is that

For mounting a dampening shoe 606; the structure of the borehole packer 608 is shown in figures 6 a-6 b.

Further, after the blast hole damper 604 is installed, a blast hole packer 608 is laid with the blast hole as the center and tightly attached to the roof rock face, and then the blast hole packer 608 is jacked up by using a single column 609, wherein the initial support force of the single column 609 is 2-3 MPa.

Before the above steps are completed, the detonating cord 7 and the pulling cord are threaded in the wire leading hole 603 and led out of the hole of the blasthole 1, taking care not to break or press the cord.

Fig. 7 shows the spatial relationship between the borehole 1, the energy concentrator 2, the explosive 3, the air column 605, the water sand bag 5, the borehole damper 604 and the internal structure, the borehole packer 608 and the internal structure, and the monomer column 609. Exemplarily, firstly, the energy-gathering tube 2 filled with the explosive 3 and the water sand bag 5 is filled into the blast hole 1, and an air column 605 is required to be left between the explosive 3 and the water sand bag 5; then, a blast hole damper 604 is loaded, a traction line connected with a lead wire hole 603 is pulled out of an orifice of a blast hole 1, then, a blast hole packer 608 is used for centering on the blast hole 1 for hole sealing, finally, a monomer column 609 is used for jacking the blast hole packer 608, and initial support force of 2-3MPa is given to ensure the support effect.

Compared with the prior art, the blasthole plugging device has the advantages that the blasthole plugging device structure convenient to process and disassemble is innovatively designed, the structure is simple, the manufacturing is convenient, and the cost is low. On one hand, the effect that the primary damping blasting energy is axially rushed out along the blast hole is realized by arranging a segmented structure of an air column 605 between the water sand bag 5 and the explosive 3; on the other hand, the effect that secondary damping blasting energy rushes out along the axial direction of the blast hole is realized by arranging a rigid-flexible structure of the blast hole damper 604; on the other hand, the effect of punching out the triple damping blasting energy along the axial direction of the blast hole is realized by arranging the supporting structure of the blast hole packer 608 and the monomer column 609. The blasthole plugging device is used for plugging, is very simple and convenient to process, manufacture and plug construction, and can provide powerful support for detecting the pre-splitting blasting roof cutting effect and improving the gob-side entry retaining technology.

Example 4

The invention also discloses a method for detecting the blasting presplitting and top cutting effects, which comprises the following steps:

plugging the blasthole 1 by using the blasthole plugging method of the embodiment 3; selecting one blast hole 1 as a detection blast hole every 20-30 meters after blasting, sequentially detaching an outer blast hole damping device and an inner blast hole damping device which are arranged in the detection blast hole from outside to inside, and detecting the gob-side entry retaining presplitting blasting roof cutting effect by adopting a drilling sight.

Specifically, after steps S101-S103 are completed, blasting and related process operations are performed. After blasting is finished, on the basis of safety protection, firstly detaching the monomer column 609, then removing the blasthole hole packer 608, finally removing the blasthole damper 604 from the blasthole 1 through a traction line, extending the drilling peeping instrument into the blasted blasthole 1, and detecting the gob-side entry retaining presplitting blasting roof cutting effect.

In the embodiment, blasting parameters and the like can be optimized through the detection effect, and illustratively, if the blasting effect is good and an expected blasting effect is obtained, the next coal mining construction is carried out; if the blasting effect is not good, blasting encryption measures are taken to carry out encrypted blasting on the gob-side entry retaining so as to improve the blasting effect.

Further, in order to better sink, fracture and crush the coal seam roof in front of the working face stope by utilizing the advanced dynamic pressure acting force formed during the working face stope, promote the coal seam roof to collapse more fully after the working face stope passes, and reduce the damage and influence on the roof in the roadway, the distance between the blasted area 610 and the working face is required to be not less than 50m, or the distance between the non-blasted area 611 and the working face is required to be always more than 50 m. The shot distance and the detection position are shown in fig. 8.

Furthermore, according to the change of the structure and the mechanical property of the top plate rock stratum, the field detection of the blasting presplitting roof cutting effect needs to be carried out in a segmented mode, namely, the blasting roof cutting effect detection is carried out at intervals of 30-50m along the trend of blasting positions. As shown in fig. 8, 2-3 adjacent blastholes 1 are selected from a certain group of top-cutting blastholes 1, the blasthole plugging device provided by the invention can be used for performing two-stage plugging of inside and outside blastholes, and the blasthole plugging device can be detached and moved as required after blasting is finished, so that the detection of the blasting pre-splitting effect can be performed. The detection standard is that mutually communicated effective cracks are formed between adjacent blastholes, as shown in fig. 9, the blasting presplitting roof cutting effect meets the construction quality requirement of gob-side entry retaining; if the effective cracks can not be formed, the charging structure, the charging quantity, the blast hole parameters and the like need to be adjusted and checked again until the top cutting effect requirement of the gob-side entry retaining is met.

Compared with the prior art, the detection method of blasting presplitting topping effect provided by the embodiment adopts the detachable blasthole plugging device to plug blastholes, the blasthole plugging device can be conveniently and quickly removed after blasting, the detection of the blasting presplitting topping effect is realized, the construction efficiency is improved, the construction cost is reduced, the target of conveniently detecting the blasting topping effect is realized, the difficult problem that the detection is abandoned due to inconvenient detection after the coal mine blasting presplitting topping is solved, and the method has important significance and value in promotion of gob-side entry retaining overall effect and popularization and application of expansion technology.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention.

Claims

1. A construction method of a roof cutting and roadway retaining cooperative anchoring and protecting structure is characterized by comprising the following steps:

step S2: constructing a roof-cutting and roadway-retaining anchor structure consisting of an in-roadway cooperative anchoring structure (11) and a roadside cooperative supporting structure (12) on the roof directly in the roadway and the roof adjacent to the gob after blasting pre-splitting;

step S3, after the construction of the waste rock blocking support body (16) is completed, a roadway-retaining closed structure is synchronously built on the outer side of the waste rock blocking support body, and the construction of the roof-cutting roadway-retaining cooperative anchoring structure is completed;

the step S1 includes the following steps:

step S11: after the stope face is formed, drilling a plurality of groups of blast holes (1) on the roof in the roadway close to the stope face from inside to outside along the direction of the roadway;

step S12: after drilling of the same group of blast holes (1), selecting the number of the segmented charging structures, the number of the energy-collecting pipes and the explosive quantity according to the surrounding rock structure, the mechanical property and the depth condition of the blast holes, and respectively filling the required explosive quantity and the detonators (4) into the corresponding energy-collecting pipes (2);

step S13: the assembled energy-gathering pipes (2) are sequentially sent into the blast hole (1), and the blast hole (1) is plugged;

directional blasting pre-splitting is carried out through an energy-gathering pipe, and mechanical connection between a direct top plate and a working face top plate is cut off;

step S1 further includes:

2-3 adjacent blastholes are selected from the same group of blastholes (1) as detection blastholes, and a detachable blasthole plugging device (6) is adopted to replace stemming for plugging;

after blasting, the blast hole plugging device (6) is removed, and blasting effect detection is carried out;

step S2 includes the following steps:

step S21: when a roadway is tunneled and before the working face is stoped, an anchor rod (19), an anchor cable I (20) and an anchor cable II (21) are used for building an in-roadway cooperative anchoring structure (11); the in-lane cooperative anchoring structure (11) consists of three secondary substructures, namely a top plate anchoring beam (13), a roadside reinforcing beam (14) and a coal side anchoring body (15);

step S22: when the working face passes the stoping, a roadside cooperative supporting structure (12) is built at the stoping hollow side of the entry retaining section; the roadside cooperative supporting structure (12) consists of three secondary substructures of a waste rock retaining support body (16), a roof cutting support body (17) and a waste rock support body (18);

step S3 includes the following steps:

step S31: a reinforcing mesh, sealing cloth, a wire gauze and a sand bag are sequentially paved from the roadside to the goaf direction, and a roadway-retaining sealing structure is formed on the outer side of the waste rock retaining support body (16);

step S32: connecting a wire netting, a sealing cloth, a reinforcing mesh and a top plate anchor net in sequence on the outer side of an I-shaped steel beam (23) for erecting gangue blocking support;

2. The method for constructing a roof-cutting drift-in-coordination anchoring structure according to claim 1, wherein in step S11, blastholes (1) are drilled and blasted in groups, and the number of blastholes (1) in the same group is 8-10;

the drilling positions of the same group of blasting holes (1) are on the same straight line, and the drilling angle is kept unchanged, so that the angles of the same group of blasting holes (1) are kept parallel.

3. The construction method of the roof cutting and roadway retaining cooperative anchoring structure as claimed in claim 2, wherein the diameter of the blasthole (1) is 50mm, the angle is 15-20 degrees, the depth is 6500-8000mm, and the eye distance is 500-700 mm.

4. The method for constructing a roof-cutting entry-retaining cooperative anchoring structure according to claim 3, wherein in step S12, each charge structure corresponds to one energy-collecting pipe (2), each energy-collecting pipe (2) has a length of 1500mm and a diameter of 42 mm;

3-4 energy-gathering pipes (2) are arranged in each blast hole (1).

5. A method of construction of a roof cutting and entry retaining co-anchored structure according to claim 4, characterized in that the blasthole depth is 6500mm, 3 energy-collecting pipes (2) are used; the first energy-collecting pipe is filled with 3 sections of explosives (3), the second energy-collecting pipe is filled with 2 sections of explosives (3), and the third energy-collecting pipe is filled with 1 section of explosives (3);

the third energy-collecting pipe is filled into a 2-3 water-saving sand bag (5), and the water sand bag (5) is filled continuously from the lower pipe orifice upwards in sequence.

6. The method for constructing a roof-cutting roadway-retaining cooperative anchoring structure according to claim 1, wherein in step S13, a plurality of sections of stemming are used for plugging the blasthole (1);