阅读说明：本技术 厚煤层综放沿顶掘进切顶卸压自动成巷方法 (Thick coal seam fully-mechanized top-tunneling top-cutting pressure relief automatic roadway forming method ) 是由 王炯 王浩森 马资敏 明灿 李文飞 张权 于光远 于 2020-12-02 设计创作，主要内容包括：涉及煤炭开采技术领域,本申请公开一种厚煤层综放沿顶掘进切顶卸压自动成巷方法,包括以下步骤：工作面计划保留巷道掘进时沿煤层顶板掘进,回采时进行超前支护和临时滞后支护,临时滞后支护装置抵接于底梁上,底梁沿留巷的走向方向铺设；在留巷采空区侧设挡矸支护装置、防侧倾装置和防陷装置,且防侧倾装置的外漏段插入预裂缝的切缝钻孔内,防陷装置与挡矸支护装置的底部固定并埋入底板煤层内。本发明,临时滞后支护装置的压力通过底梁均匀分散到留巷巷道的底板,有效防止底臌和滞后支护陷入底板中；利用挡矸支护装置、防侧倾装置、防陷装置、临时滞后支护装置和底梁实现工作面间不留煤柱,保留一条回采巷道给下一个工作面使用。(The application discloses a thick coal seam fully mechanized caving top-cutting pressure relief automatic roadway forming method, which relates to the technical field of coal mining and comprises the following steps: the working face plans to keep the tunneling along the coal seam roof when tunneling, and carries out forepoling and temporary lagging support when stoping, wherein the temporary lagging support device is abutted against the bottom beam, and the bottom beam is laid along the heading direction of the roadway; and a waste rock blocking support device, an anti-roll device and an anti-sinking device are arranged on the side of the roadway mining area, an outer leakage section of the anti-roll device is inserted into a cutting seam drill hole of the pre-crack, and the anti-sinking device and the bottom of the waste rock blocking support device are fixed and buried in a coal seam of a bottom plate. According to the invention, the pressure of the temporary lag support device is uniformly dispersed to the bottom plate of the entry retaining roadway through the bottom beam, so that floor heave and lag support are effectively prevented from being sunk into the bottom plate; and the coal pillars are not left between the working surfaces by utilizing the waste rock blocking supporting device, the anti-roll device, the anti-sinking device, the temporary lagging supporting device and the bottom beam, and a stoping roadway is reserved for the next working surface.)

1. The thick coal seam fully mechanized caving top-cutting pressure relief automatic roadway forming method is characterized by comprising the following steps of:

when a working face planned entry retaining roadway (9) is tunneled, tunneling is carried out along the top plate of the thick coal seam to be mined;

the advanced working face carries out reinforcement supporting on a top plate and a counter wall of a planned entry retaining roadway (9);

reinforcing the supporting structure after exceeding, drilling a cutting seam and a hole (7) on the top plate on the side of the front wall of the roadway retaining roadway (9), and then performing directional presplitting blasting to form a presplitting seam (8);

the method comprises the following steps of carrying out forepoling during stoping of a working face, arranging a temporary lagging support device on the retreating working face, wherein the temporary lagging support device is abutted against a bottom beam (14), and the bottom beam (14) is at least one row and is laid along the trend direction of a roadway (9); a waste rock blocking support device, an anti-roll device and an anti-sinking device are arranged on the side of the retained roadway goaf (15), the anti-roll device is fixed with the waste rock blocking support device, an outer leakage section of the anti-roll device is inserted into a cutting seam drilling hole (7) of a pre-crack (8), and the anti-sinking device is fixed with the bottom of the waste rock blocking support device and is buried in a coal seam of a bottom plate;

and (3) finishing the stoping of the working face, removing the temporary lagging support device in the retained roadway (9) after the roadway is stable, sealing the goaf (15) and finishing the retained roadway.

2. The method according to claim 1, characterized in that the waste rock retaining and supporting device comprises telescopic U-shaped steel (11), a reinforcing mesh (16) and a metal mesh (10), two telescopic U-shaped steel (11) are fixed by overlapping through a clamping flange (17) and are sequentially arranged at intervals along the running direction of the roadway retaining roadway (9), two adjacent telescopic U-shaped steel (11) are connected with the clamping flange (17) through a connecting rod (18), the telescopic U-shaped steel (11) sequentially hangs the reinforcing mesh (16) and the metal mesh (10) towards one side of the goaf (15), and the reinforcing mesh (16) and the metal mesh (10) are overlapped and are bound and fixed through wires.

3. The method as claimed in claim 2, wherein the anti-roll device is a round bar (22), one end of the round bar (22) is inserted into the telescopic U-shaped steel (11) and welded, and the other end is inserted into the slot drilling hole (7), and the round bar (22) and the upper part of the telescopic U-shaped steel (11) are welded with an inclination angle which is the same as the slot angle;

the anti-sinking device is a steel plate (27), the lower parts of the steel plate (27) and the telescopic U-shaped steel (11) are horizontally welded, and then the steel plate (27) and the bottom of the telescopic U-shaped steel (11) are embedded into a column socket on site.

4. The method according to claim 1, characterized in that the roof of the entry retaining roadway (9) is reinforced and supported by constant-resistance anchor cables (1), and the sublevel of the entry retaining roadway (9) is reinforced and supported by common anchor cables (2) of the roadway side to prevent caving.

5. The method according to claim 4, characterized in that the constant-resistance anchor cables (1) are arranged perpendicular to the roof direction, a plurality of rows are arranged along the trend of the entry retaining roadway (9), the first row of constant-resistance anchor cables (1) adjacent to the front side of the entry retaining roadway are connected by a trend W-shaped steel belt (6), the trend W-shaped steel belt (6) is arranged along the trend of the entry retaining roadway (9), the rest of the plurality of rows of adjacent constant-resistance anchor cables (1) are connected by a trend W-shaped steel belt (3), and the trend W-shaped steel belt (3) is arranged along the transverse direction of the entry retaining roadway (9).

6. A method according to claim 5, wherein the transverse spacing of the first and second rows of constant resistance cables (1) is less than the transverse spacing of the remaining rows of constant resistance cables (1).

7. A method according to claim 5, wherein the rows of constant resistance cables (1) are staggered, the pitch of the first row of constant resistance cables (1) being 1/2 of the pitch of the remaining rows of constant resistance cables (1).

8. A method according to claim 4, characterized in that prior to the reinforcing support, rock coring is performed every 50m in the planned entry drive (9), and the roof lithology profile of the entry drive (9) is drawn from the cores taken in the entry drive (9); and designing the height of the directional joint cutting, the angle of the directional joint cutting and the length of the constant-resistance anchor cable (1) according to the lithologic section diagram of the top plate, and determining the explosive loading conditions in the directional joint cutting holes with different joint cutting heights according to the field blasting experiment condition and the single-hole fracture rate.

9. The method as claimed in claim 4, wherein in the step of reinforcing and supporting the sublevel of the entry retaining roadway (9) by using the common anchor cables (2) for roadway sides, two common anchor cables (2) for roadway sides are additionally arranged in the solid coal of the sublevel of the entry retaining roadway (9), wherein one common anchor cable (2) for roadway sides is positioned at a position, 1 meter higher than the top plate, of the sublevel of the entry retaining roadway (9) and is obliquely arranged towards the top plate, and an included angle of 45 degrees is formed between the common anchor cables and the horizontal direction; the other side is positioned at the height of the assistant side of the retained roadway (9) and 1 meter away from the bottom plate, and is perpendicular to the assistant side of the retained roadway (9) for repairing.

10. The method as claimed in claim 1, wherein the temporary lagging support means comprises five rows of single hydraulic props (13) or portal frames, the lagging support distance is 250m, the bottom beams (14) are arranged at the bottoms of a row of the single hydraulic props (13) or portal frames, and the temporary lagging support means is withdrawn to the working face for circular support after the caving zone of the goaf (15) is stabilized.

Technical Field

The application relates to the field of coal mining in general, and particularly relates to a thick coal seam fully mechanized caving top-cutting pressure relief automatic roadway forming method.

Background

At present, China is the largest coal-producing country in the world, and coal occupies the dominant position in primary energy consumption in China. In the coal resource reserves which have been proved in China, the reserve of a thick coal seam accounts for about 44%, and the main mining method of a thick coal seam mine is a longwall fully-mechanized top-coal caving mining method. However, in the longwall mining method, because protective coal pillars need to be arranged between working faces, coal resources are wasted, and the recovery rate of coal resources in a mine is low. In the thick coal seam caving coal mining, the loss of a coal pillar resource part is larger due to the larger thickness of the coal seam, and the existence of the coal pillar can cause the stress concentration above the coal pillar, so that geological disasters such as roof fall, rib spalling, floor heave and the like can easily occur along a hollow side roadway. Meanwhile, the coal pillars are reserved, so that the ground surface above the goaf and the ground surface above the coal pillars are subjected to uneven settlement, large tensile cracks are generated on the ground surface due to uneven settlement of the ground surface, ground surface houses and vegetation are damaged, and ground surface shallow groundwater is damaged.

In order to solve a series of problems caused by reserving coal pillars in a long-wall fully-mechanized top coal caving mining method of a thick coal seam, a coal pillar-free self-entry technology is gradually applied. The coal-pillar-free self-propelled roadway is a technology that after a stoping roadway is reinforced and supported, directional pre-splitting blasting is carried out on the side of a roadway where a goaf is to be formed, a roof is subjected to joint cutting according to a designed position, after the joint cutting is finished, along with the stoping of a coal bed on a working face, under the action of mine pressure, the roof of the goaf collapses along the pre-splitting joint cutting to form a roadway side, and the roadway is reserved by using part of space of the original roadway and a waste rock blocking support to serve as the stoping roadway of the next working face.

However, for the fully mechanized top coal caving mining method of the thick coal seam, because the thickness of the coal seam is larger, and the thickness of the general coal seam is larger than the height of the roadway, one mode is to dig along the top plate of the mining coal seam when the mining roadway is excavated, and at the moment, because the top plate above the mining roadway is a rock stratum, the roadway is easier to support, and the excavation speed of the roadway is faster. However, because bottom coal is reserved on the general bottom plate of the top excavation roadway, coal beds with different thicknesses are reserved on the bottom plate of the stoping roadway, and a large-range floor heave can occur on the stoping roadway under the influence of mine pressure in the stoping process. In the traditional thick coal seam coal pillar-free automatic roadway forming method, a once-mining full-height coal mining method is adopted, and the bottom plate of a stoping roadway is generally a rock stratum, so that the condition that a temporary lagging support device is toppled or inserted into the bottom plate when bottom coal bottom plate floor heave is left on the bottom plate of the stoping roadway is not considered, and the condition that a waste rock retaining support is sunk into the bottom plate of the coal seam is not considered.

In view of this, it is urgently needed to improve the existing thick coal seam non-pillar automatic roadway forming method to improve the support stability of the roadway retaining and safely and stably retain the stoping roadway of the working face for the stoping of the next working face.

Disclosure of Invention

One of the main purposes of the present application is to overcome the above-mentioned unstable defect of bottom plate support of the mining roadway in the thick coal seam tunneling mode along the top plate in the prior art, and to provide a thick coal seam fully mechanized caving, top cutting and pressure relief automatic roadway forming method, which includes the following steps:

when a working face planned entry retaining roadway is tunneled, tunneling is carried out along the top plate of the mined thick coal seam;

the advanced working face carries out reinforcement supporting on a top plate and a side wall of a planned entry retaining roadway;

reinforcing the supporting structure after the roadway is built, drilling a cutting seam on a top plate on the side of the front wall of the roadway, and then performing directional presplitting blasting to form a presplitting crack;

the method comprises the following steps of carrying out forepoling during stoping of a working face, arranging a temporary lagging support device on the retreating working face, wherein the temporary lagging support device is abutted against a bottom beam, and the bottom beam is at least one row and is laid along the trend direction of a roadway; the side of a roadway mining area is provided with a waste rock blocking support device, an anti-roll device and an anti-sinking device, the anti-roll device is fixed with the waste rock blocking support device, an outer leakage section of the anti-roll device is inserted into a pre-cracked joint-cutting drill hole, and the anti-sinking device is fixed with the bottom of the waste rock blocking support device and is buried in a bottom plate coal seam.

And (4) finishing the stoping of the working face, removing the temporary lagging support device in the retained roadway after the roadway is stable, sealing the goaf and finishing the retained roadway.

According to an embodiment of the invention, the waste rock blocking and supporting device comprises telescopic U-shaped steel, a reinforcing mesh and a metal mesh, wherein two pieces of telescopic U-shaped steel are fixed through a flange in an overlapping mode and are sequentially arranged at intervals along the moving direction of a roadway retaining roadway, two adjacent pieces of telescopic U-shaped steel are connected with the flange through a connecting rod, the reinforcing mesh and the metal mesh are sequentially hung on one side, facing a goaf, of the telescopic U-shaped steel, and the reinforcing mesh and the metal mesh are overlapped and are bound and fixed through iron wires.

Furthermore, the anti-roll device is round steel, one end of the round steel extends into the telescopic U-shaped steel and is welded and fixed, the other end of the round steel is inserted into the cutting seam drilling hole, and the round steel and the upper part of the telescopic U-shaped steel are welded to form an inclination angle which is the same as the cutting seam angle;

the anti-sinking device is a steel plate, the steel plate is horizontally welded with the lower portion of the telescopic U-shaped steel, and then the steel plate and the bottom of the telescopic U-shaped steel are embedded into the column nest on site.

According to one embodiment of the invention, the top plate of the entry retaining tunnel is reinforced and supported by using the constant-resistance anchor cables, and the auxiliary side of the entry retaining tunnel is reinforced and supported by using the common anchor cables of the side wall, so that the side wall is prevented from being chipped.

Further, the constant-resistance anchor cables are perpendicular to the top plate direction, multiple rows are arranged along the trend of the entry retaining roadway, the first row of constant-resistance anchor cables close to the side of the positive side of the entry retaining roadway are connected through a trend W-shaped steel belt, the trend W-shaped steel belt is arranged along the trend direction of the entry retaining roadway, adjacent constant-resistance anchor cables of the remaining multiple rows are connected through a trend W-shaped steel belt, and the trend W-shaped steel belt is arranged along the transverse direction of the entry retaining roadway.

Further, the transverse distance between the first row and the second row of constant-resistance anchor cables is smaller than that between the remaining rows of constant-resistance anchor cables.

Furthermore, all the rows of constant-resistance anchor cables are distributed in a staggered mode, and the row distance of the first row of constant-resistance anchor cables is 1/2 of the row distances of the remaining multiple rows of constant-resistance anchor cables.

Further, before reinforcing support, performing rock coring every 50m in a planned entry retaining roadway, and drawing a top plate lithologic section of the entry retaining roadway according to a core taken out from the entry retaining roadway; and designing the height of the directional joint cutting, the angle of the directional joint cutting and the length of the constant-resistance anchor cable according to the lithologic section diagram of the top plate, and determining the explosive loading conditions in the directional joint cutting holes with different joint cutting heights according to the field blasting experiment condition and the single-hole fracture rate.

Further, in the step of reinforcing and supporting the auxiliary wall of the entry retaining roadway by using the common anchor cables for the roadway wall, two common anchor cables for the roadway wall are additionally arranged in the solid coal of the auxiliary wall of the entry retaining roadway, wherein one of the two common anchor cables is positioned at the position, 1 meter away from the top plate, of the auxiliary wall of the entry retaining roadway and is obliquely driven into the top plate, and an included angle of 45 degrees is formed between the one common anchor cable and the horizontal direction; and the other side is positioned at the height of the auxiliary side of the retained roadway, which is 1 meter away from the bottom plate, and is vertical to the auxiliary side of the retained roadway for repairing and driving.

According to an embodiment of the invention, the temporary lag support device comprises five rows of single hydraulic struts or portal supports, the lag support distance is 250m, the bottom beam pad is arranged at the bottom of one row of single hydraulic struts or portal supports, and after a goaf caving zone collapses stably, the temporary lag support device is withdrawn to a working face for cycle support.

According to the technical scheme, the thick coal seam fully mechanized caving method for automatically forming the roadway along top tunneling, top cutting and pressure relief has the advantages and positive effects that: the method is suitable for planning entry retaining along the top plate tunneling of the mined coal seam during the fully mechanized top coal caving mining of the thick coal seam, and performing combined support on an beyond working face by using a temporary lag support device and a bottom beam, wherein the bottom beam is arranged along the trend direction of the entry retaining tunnel, so that the pressure of the temporary lag support device is uniformly dispersed onto a bottom plate coal seam of the entry retaining tunnel through the bottom beam, and the method can effectively prevent the situation that the temporary lag support is toppled or sunk into the bottom plate coal seam when the pressure is applied due to the fact that the bottom plate coal seam is soft, and reduce the problem of unstable support due to deformation of the bottom plate; and the anti-roll device, the anti-sinking device and the waste rock blocking support device are fixed, and the waste rock blocking support device and the anti-sinking device are embedded into the coal seam of the roadway retaining roadway bottom plate, so that the reinforcing support, the anti-roll device, the anti-sinking device and the waste rock blocking support device realize the mutual restraining and supporting effects on the roadway retaining roadway bottom plate and the pre-cracks, the stability of the top plate in the caving motion process is effectively improved, and the stability of the roadway retaining roadway when the next working face is reused is improved.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and together with the description, serve to explain the principles of the invention.

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without inventive exercise.

FIG. 1 is a schematic flow diagram of one embodiment of the present invention.

Fig. 2 is a plan view of a mining operation according to an embodiment of the present invention.

Figure 3 is a cross-sectional view of a work surface of one embodiment of the present invention.

Fig. 4 is a cross-sectional view of a roadway roof constant-resistance anchor cable reinforcing support according to an embodiment of the invention.

Fig. 5 is a top view of a constant-resistance cable reinforcing support roof according to an embodiment of the present invention.

Fig. 6 is a cross-sectional view of a kerf placement of one embodiment of the invention.

FIG. 7 is a top plan view of a slit hole arrangement top plate in accordance with one embodiment of the present invention.

FIG. 8 is a schematic illustration of the slotted hole charging of one embodiment of the present invention.

Fig. 9 is a top view of a constant resistance anchor cable and slotted hole arrangement top plate according to one embodiment of the present invention.

Fig. 10 is a schematic view of a conventional anchor cable support for roadway sides according to an embodiment of the present invention.

Fig. 11 is a schematic illustration of a lane keeping roadway partition in accordance with an embodiment of the present invention.

Fig. 12 is a cross-sectional view of a forepoling system in accordance with one embodiment of the present invention.

Figure 13 is a cross-sectional view of a lagging support of one embodiment of the present invention.

Figure 14 is a top view of a lag bracing roof in accordance with one embodiment of the present invention.

Figure 15 is a top view of a fore and aft support of one embodiment of the present invention.

Fig. 16 is a schematic view of a retaining support of one embodiment of the present invention.

Figure 17 is a top plan view of the lagging and retaining support floor of one embodiment of the present invention.

Figure 18 is a cross-sectional view of a stabilization zone support according to one embodiment of the present invention.

Wherein the reference numerals are as follows:

the anchor rope comprises a constant-resistance anchor rope 1, a roadway side common anchor rope 2, an inclined W-shaped steel belt 3, a top plate common anchor rod 4, a top plate common anchor rope 5, a trend W-shaped steel belt 6, a kerf drilling hole 7, a pre-crack 8, a roadway retaining roadway 9, a metal mesh 10, telescopic U-shaped steel 11, a top beam 12, a single hydraulic prop 13, a bottom beam 14, a goaf 15, a reinforcing mesh 16, a flange 17, a connecting rod 18, an advance influence area 19, a lag influence area 20, a roadway forming stable area 21, round steel 22, a working face 23, a transportation roadway 24, a return air roadway 25, lower end triangular coal 26 and a steel plate 27.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

In order to overcome the problems in the thick coal seam roof cutting pressure relief automatic roadway forming method in the prior art, as shown in fig. 1, fig. 2, fig. 3 and fig. 4, the invention discloses a thick coal seam fully mechanized caving roof cutting pressure relief automatic roadway forming method, which comprises the following steps:

s100, as shown in the figures 2 and 3, when a working face planned entry retaining roadway 9 is tunneled, tunneling is carried out along the top plate of the mined thick coal seam;

s200, as shown in figures 4 and 5, a front working face carries out reinforcement supporting on a top plate and a counter wall of a planned entry retaining roadway 9;

s300, as shown in figures 4 and 5, reinforcing the supporting structure after overtaking, and performing directional blasting on a top plate on the front side of a roadway 9 to form a local straight and continuous pre-crack 8;

s400, as shown in figures 11, 12, 13 and 15, performing advance support during mining of a working face, arranging a temporary lagging support device on the overtaking working face, wherein the temporary lagging support device is abutted against the bottom beam 14, and the bottom beam 14 is at least one row and is laid along the trend direction of the entry retaining roadway 9; and a waste rock blocking support device, an anti-roll device and an anti-sinking device are arranged on the side of the retained roadway goaf 15, the anti-roll device and the waste rock blocking support device are fixed, an outer leakage section of the anti-roll device is inserted into the cutting seam drilling hole 7 of the pre-crack 8, and the anti-sinking device and the bottom of the waste rock blocking support device are fixed and buried in a bottom plate coal layer.

And S500, as shown in figure 18, completing the stoping of the working face, removing the temporary lagging support device in the roadway 9 after the roadway is stabilized, and sealing the goaf 15 to complete the roadway.

As shown in fig. 3, when the planned entry retaining roadway 9 is tunneled along the coal seam roof, since the top plate of the planned entry retaining roadway 9 is rock, the supporting is easy, and the tunneling speed is high. However, a part of the triangular bottom coal 26 pressed under the stoping roadway is lost on the bottom plate of the top excavation roadway, when the thickness of the coal layer is 6 meters, the bottom coal with the thickness of about 3 meters is generally remained, because the coal layer is soft, the bottom plate is easy to heave when being influenced by mining, and the single body is easy to topple or insert into the bottom plate for support failure when being supported;

as for the structure of the entry retaining tunnel 9, specifically, as shown in fig. 11 and 15, planned entry retaining tunnels 9 at different positions are affected differently by mining during the working face advancing process. The leading section of the face is affected by the leading bearing pressure, referred to as the leading affected zone 19; after the working face is pushed, the top plate of the goaf 15 begins to collapse, and a certain time is needed for the compaction stability of the waste rock in the goaf 15 from beginning to collapse, so that a hysteresis influence area 20 is formed in the area behind the rack close to the working face, the hysteresis influence area 20 is required to be supported by the top plate and also required to be supported by the waste rock, the waste rock in the goaf 15 is prevented from entering the entry retaining roadway 9, and the entry retaining roadway 9 is reserved to be used as an air return roadway 25 for the next working face to recover. With the continuous advancing of the working face, when the lagging working face of the entry retaining roadway 9 is far away, the collapse gangue of the goaf 15 is compacted stably, the movement of the top plate of the goaf 15 basically tends to be stable, at the moment, the temporary lagging support device can be removed when the goaf enters the entry forming stable area 21, and only the gangue retaining support is reserved. It can be understood that the supporting device needs to detect according to the data of on-site mine pressure monitoring during evacuation, and after the top plate of the entry retaining section is stable, the mine pressure monitoring data comprise the moving-in amount of the top bottom plate, the shrinkage amount of the single prop plunger, the pressure of the single prop and the horizontal stress of the goaf tend to be stable, and then the temporary supporting equipment can be removed at intervals.

The technical scheme provided by the invention is suitable for a roadway tunneled along a roof in a thick coal seam fully-mechanized top coal caving mining method, a temporary lag support device and a bottom beam 14 are utilized to carry out combined support on an overtop working face, the bottom beam 14 is arranged along the trend direction of a roadway 9, the pressure of the temporary lag support device is uniformly dispersed to a bottom coal seam of the roadway 9 through the bottom beam 14, the situation that the temporary lag support falls or sinks into the bottom coal seam when the floor coal seam is subjected to pressure and generates floor heave due to the fact that the material of the bottom coal seam is soft can be effectively prevented, and the problem of unstable support caused by deformation of the bottom floor is reduced; and the anti-roll device, the anti-sinking device and the waste rock blocking support device are fixed, and the waste rock blocking support device and the anti-sinking device are embedded into the coal seam of the bottom plate of the entry retaining roadway 9 together, so that the reinforcing support anchor cable, the anti-roll device, the anti-sinking device and the waste rock blocking support device realize the mutual control and support effect of the bottom plate and the pre-crack 8 of the entry retaining roadway 9, the stability of the top plate in the collapse motion process is effectively improved, and the stability of the entry retaining roadway 9 in the reuse of the next working face is improved.

By directional joint-cutting blasting and ore pressure, one roadway of the previous working face can be reserved for the next working face, and not only is a protective coal pillar between the working faces cancelled, so that the recovery rate of mine coal resources is effectively improved, but also the tunneling engineering quantity of the roadway can be reduced by 50%, and further the coal mining cost is reduced. Because the protective coal pillars between the working faces are cancelled, the problem of stress concentration generated in the coal pillars reserved is solved, the uneven settlement of the earth surface can be changed into even settlement, the damage to earth surface houses, vegetation and shallow groundwater is greatly relieved, and meanwhile, because the protective coal pillars are not reserved between the working faces, the recovery rate of mine coal resources can be greatly improved.

In step S100, when the working face planned entry retaining roadway 9 is tunneled, the tunneling is performed along the roof of the thick coal seam to be mined.

In this step, at this time, because the top plate of the entry retaining roadway 9 is rock, the support is easy, and the excavation speed of the entry retaining roadway 9 is high, but bottom coal is generally left along the bottom plate of the planned entry retaining roadway 9.

In a preferred embodiment, as shown in fig. 3, when the working face 23 is excavated, the transportation roadway 24 of the planned entry retaining roadway 9 in the working face 23 is excavated along the top plate of the coal seam, at this time, because the top plate of the transportation roadway 24 is made of mudstone, it is easier to support relative to the coal seam, and therefore the excavation speed of the transportation roadway 24 is faster, but bottom coal with a thickness of 3m is left on the bottom plate of the transportation roadway 24, because the coal seam is softer, the bottom plate is easy to heave when being influenced by mining, and the support is easy to topple over or insert into the bottom plate when the single body support fails.

Specifically, as shown in fig. 2, in an embodiment of a plan view of a mining project, the second mining area includes a first working surface, a second working surface and a third working surface, the working surface 23 is the second working surface shown in the figure, and the second transportation gateway of the second working surface is used as a third return air gateway of the third working surface.

It should be noted that when the top coal caving working face is stoped in the fully mechanized mining of the thick coal seam, 3-5 end supports on the side of the planned entry retaining roadway 9 on the working face do not discharge coal.

In step S200, the top plate and the counter wall of the planned entry retaining roadway 9 are reinforced and supported, and the construction can be performed with the reinforcement and support advanced by 100 m.

In a preferred embodiment, in the step of reinforcing and supporting the top plate of the entry retaining roadway 9 by using the constant-resistance anchor cables 1, the auxiliary side of the entry retaining roadway 9 is reinforced and supported by using the common anchor cables 2 for the roadway side. The constant-resistance anchor cable 1 reinforces and supports the top plate of the entry retaining roadway 9, and can ensure the stability of the entry retaining roadway 9 in the roof cutting process and the period pressure coming period. Specifically, as shown in fig. 4, 5, and 10, the reinforcing bar should be constructed in advance of the working face by 100 m. And the reinforcing support is carried out under the condition that the common roof anchor rod 4 and the common roof anchor cable 5 are arranged on the roof. The conventional roof common anchor rod 4 and the roof common anchor cable 5 are connected by steel belts, and the arrangement direction of the steel belts is perpendicular to the trend of the entry retaining roadway 9. In the embodiment, the constant-resistance anchor cable 1 is adopted, can bear large deformation compared with the traditional anchor cable, has stronger supporting capacity on the top plate, and is used for reinforcing and supporting the top plate; the deformation rate of the common anchor cable is relatively low, and the anchor cable is suitable for the counter side with relatively small deformation in the mining and falling processes.

As shown in fig. 5 and 10, the reinforced support of the constant-resistance anchor cable 1 has the following specific arrangement and structure:

the constant-resistance anchor cables 1 are arranged in the direction perpendicular to the top plate, multiple rows are arranged along the trend of the entry retaining roadway 9, the first row of constant-resistance anchor cables 1 close to the side of the entry retaining roadway and facing the side are connected through the trend W-shaped steel belt 6, the trend W-shaped steel belt 6 is arranged along the trend direction of the entry retaining roadway 9, the adjacent constant-resistance anchor cables 1 in the multiple rows are connected through the trend W-shaped steel belt 3, and the trend W-shaped steel belt 3 is arranged along the transverse direction of the entry retaining roadway 9. The side of keeping somewhere the lane is just group side promptly and is the joint-cutting side promptly, arranges first row of constant resistance anchor rope 1 along the 9 trends of keeping somewhere the lane and fixes through the trend W shaped steel area 6 of the same trend, can effectively provide better supporting effect for the atress of joint-cutting side.

Further, the transverse distance between the first row and the second row of constant-resistance anchor cables 1 is smaller than that between the remaining rows of constant-resistance anchor cables 1. The force of the constant-resistance anchor cable 1 is gradually reduced as the anchor cable is far away from the slitting side, so that the transverse spacing of the rest columns can be properly reduced.

Further, all the rows of constant-resistance anchor cables 1 are arranged in a staggered manner, and the row pitch of the first row of constant-resistance anchor cables 1 is 1/2 of the row pitch of the remaining multiple rows of constant-resistance anchor cables 1. The constant-resistance anchor cables 1 which are distributed in a staggered mode can effectively enlarge the layout area of the anchor cables, dead-angle-free supporting is carried out on the position of the top plate, and the row distance of the first row of constant-resistance anchor cables 1 on the joint cutting side in the moving direction of the roadway 9 can be properly shortened.

The transverse distance between the first row of constant-resistance anchor cables 1 and the cutting seam drill hole 7 is required to be more than or equal to 500mm, the first row of constant-resistance anchor cables 1 on the cutting seam side are prevented from being damaged by directional presplitting blasting, and the first row of constant-resistance anchor cables 1 on the cutting seam side are prevented from being damaged when the working face end support moves in a staggered mode into the planned entry retaining roadway 9. Specifically, the constant-resistance anchor cables 1 are distributed in 5 rows in a staggered mode, the distance between the first row of constant-resistance anchor cables 1 on the side of the front side of the retained roadway (namely the joint cutting side) and the front side of the retained roadway is 700mm, and the row pitch is 800 mm; the second row is 825mm away from the first row; the distance between the 3 rd row and the second row is 975mm, the distance between the fourth row and the 3 rd row is 975mm, the distance between the fifth row and the 9 th auxiliary side of the entry retaining roadway is 550mm, and the row distance between the second row, the 3 rd row, the fourth row and the fifth row is 3200 mm. The row spacing of the first row and the second row of constant-resistance anchor cables 1 on the side of the front side of the retained roadway is dense, and the row spacing of the other 3 rows of constant-resistance anchor cables 1 is sparse, so that the structural arrangement is used for enhancing the supporting strength of the roadway roof on the joint cutting side through the constant-resistance anchor cables 1.

The first row of constant-resistance anchor cables 1 on the side (i.e. the joint-cutting side) of the roadway front side are connected by the W-shaped steel belts 6 arranged along the direction of the roadway 9, each row of the W-shaped steel belts 6 is provided with three anchor cable holes, namely, every three initial supporting positions of the first row of constant-resistance anchor cables 1 on the joint-cutting side are connected by the W-shaped steel belts 6, the second row of the constant-resistance anchor cables 1 is lapped with the first row of the W-shaped steel belts 6, namely, the second row of the constant-resistance anchor cables 1 is connected by the W-shaped steel belts 6 from the initial supporting position, and the W-shaped steel belts 6 are parallel to the direction of the roadway 9. Specifically, the W-shaped steel belt 6 is 2.2m long along the heading of the entry retaining roadway 9, and 3 holes are expanded.

The row spacing of four rows of constant-resistance anchor cables 1 on the non-entry retaining side is 2 times that of the first row of constant-resistance anchor cables 1 on the lancing side, and from the lancing side, the constant-resistance anchor cables 1 are arranged in a staggered mode, so that the second row and the fourth row are adjacent in the transverse direction, and the third row and the fifth row are adjacent in the transverse direction, therefore, the second row of constant-resistance anchor cables 1 and the fourth row of constant-resistance anchor cables 1 are connected by inclined W-shaped steel belts 3, from the lancing side, the third row of constant-resistance anchor cables 1 and the fifth row of constant-resistance anchor cables 1 are connected by inclined W-shaped steel belts 3, and the inclined W-shaped steel 3 is perpendicular to the heading of an entry retaining roadway 9, namely the inclined W-shaped steel 3 is parallel to the entry retaining roadway 9. Specifically, the W-shaped steel strip 3 was 2.55m long along the inclination of the entry retaining roadway 9, and 2 holes were enlarged.

Further, before reinforcing support, rock coring is performed in the planned entry retaining roadway 9 every 50m, and a roof lithology section of the entry retaining roadway 9 is drawn according to a core taken out from the entry retaining roadway 9; according to a roof lithologic section diagram, the height of the directional joint cutting, the angle of the directional joint cutting and the length of the constant-resistance anchor cable 1 are designed, and according to the field blasting experiment condition and the single-hole fracture rate (the single-hole fracture rate is the length of the fracture section divided by the hole depth), the explosive loading conditions in the directional joint cutting holes with different joint cutting heights are determined.

According to the roof lithology profile of the entry retaining roadway 9, the following data are determined:

the height of the directional kerf is designed in a segmented mode, and the formula is as follows: h₁＝2.6*H₂(ii) a Wherein H₁Is the height of the cutting seam H₂The working face is adopted for height.

The orientation cutting seam angle is as follows: when the mining height of the working face is less than or equal to 1m, the joint cutting angle is 15-20 degrees, and when the mining height of the working face is more than 1m, the joint cutting angle is 10-15 degrees.

The length of the constant-resistance anchor cable 1 is designed in a segmented mode, and the formula is as follows: l is₁＝H₃+2.0m, wherein L₁The length of the anchor cable 1 is constant, H₃To orient the kerf height.

In a preferred embodiment, as shown in fig. 4, 10 and 12, a common anchor cable 2 for a roadway side is used to reinforce and support a sublevel of a roadway 9, specifically: two common anchor cables 2 for the roadway sides are additionally arranged in the solid coal of the auxiliary side of the roadway-retained roadway 9, wherein one of the common anchor cables 2 is positioned at a position 1 meter higher from the top plate of the auxiliary side of the roadway-retained roadway 9, and is obliquely driven into the top plate to form an included angle of 45 degrees with the horizontal direction; and the other side is positioned at the height of the 9 auxiliary walls of the retained roadway, which is 1 meter away from the bottom plate, and is perpendicular to the 9 auxiliary walls of the retained roadway for repairing and driving, so that the retained roadway is prevented from being broken.

The step effectively prevents the problem of hanging the top plate caused by the rib spalling of the auxiliary wall when the top coal caving working face of the fully mechanized mining of the thick coal seam is mined. Specifically, the diameter of the common anchor cable 2 for the roadway walls is 18.9mm, the length of the common anchor cable is 6300mm, one line of the common anchor cable is perpendicular to the 9 auxiliary walls of the roadway retained, one line of the common anchor cable is inclined to the 9 auxiliary walls of the roadway retained, and the spacing between the common anchor cable and the auxiliary walls is 900mm multiplied by 1600 mm.

It should be noted that when the constant-resistance anchor cable 1 or the common anchor cable 2 on the roadway side is additionally installed, if the anchor cable or the anchor rod is already installed in the roadway 9, the existing anchor cable, anchor rod and steel belt need to be slightly staggered.

And step S300, reinforcing the supporting structure after exceeding, and performing directional blasting on the top plate on the front side of the entry retaining roadway 9 to form a local straight and continuous pre-crack 8.

Specifically, as shown in fig. 6-10, the advanced repaired constant-resistance anchor cable 1 and the roadway side common anchor cable 2 are subjected to advanced kerf drilling construction of not less than 50m, then a kerf drilling hole 7 is constructed on a top plate on the front side (namely the working face side) of the roadway retaining roadway 9, top cutting is carried out by charging through a directional blasting energy-gathering technology, and a pre-crack 8 is formed on the top plate of the roadway retaining roadway 9; the kerf drilling holes 7 are sequentially arranged along the trend of the reserved planned roadway 9, and the distance is 500 mm. Specifically, the kerf drilling 7 is at an angle of 15 ° to the vertical roof direction.

Specifically, the slitting drilling 7 and the directional presplitting blasting cannot be operated simultaneously, and the directional presplitting blasting is generally operated independently in the early shift overhaul class. It is contemplated that the slotted borehole 7 is drilled and then charged as quickly as possible for directional presplitting blasting to avoid hole collapse.

Specifically, as shown in fig. 8, the directional energy-gathered blasting technology is used in the kerf drilling holes 7, non-coupled charging is adopted, the charging amounts in different lithologies are finally determined by field tests according to the lithology conditions of the depths of the kerf drilling holes 7, the mining emulsion explosive needs to be installed in an energy-gathered pipe to realize the directional energy-gathered blasting technology, and the mud sealing length in the kerf drilling holes 7 is not less than 2 m. The directional presplitting blasting can select 5-8 blast holes to be detonated at one time according to the hardness degree and the breaking condition of a top plate rock stratum on site and the power of a detonator initiator.

For step S400, advance support is carried out during stoping of the working face, a temporary lag support device is arranged on the working face behind, the temporary lag support device abuts against the bottom beam 14, the bottom beam 14 is at least one row and is laid along the trend direction of the entry retaining roadway 9; and a waste rock blocking support device, an anti-roll device and an anti-sinking device are arranged on the side of the retained gob 15, the anti-roll device and the anti-sinking device are fixed with the waste rock blocking support device, and the outer leakage section of the anti-roll device is inserted into the cutting seam drilling hole 7 of the pre-crack 8.

It can be understood that when the fully mechanized top coal caving plan entry retaining roadway 9 in the thick coal seam is tunneled along the top, the bottom plate is the coal seam, the gangue blocking support needs to take measures to prevent the coal seam from inclining, and the temporary lagging support device is prevented from sinking into the coal seam of the bottom plate or falling.

In a preferred embodiment, as shown in fig. 10, in the step of advance support during face extraction, the single hydraulic props 13 or portal supports are arranged in multiple rows along the running direction of the entry retaining roadway 9, the row distance of each row of single hydraulic props 13 or portal supports is 1000mm, the upper end of each row of single hydraulic props 13 or portal supports is provided with a top beam 12, and the top beam 12 is abutted against the top plate.

Specifically, the thick coal seam fully mechanized caving mining advance support adopts 3 rows of single hydraulic support columns 13 or gate type supports to prop against a top plate, and the advance support distance is 50 m. The entry retaining roadway 9 is located in the working face advance influence area 19 and needs to be reinforced for supporting. The top beam 12 may be embodied as an articulated top beam 12. Because disturbance of working face extraction on the advance area is weakened after directional energy-gathered blasting roof cutting is adopted, 3 rows of single hydraulic struts 13 are matched with the hinged top beam 12 to carry out advance support on the temporary support of the advance influence area 19, and the hinged top beam 12 matched with each row of single hydraulic struts 13 is arranged along the direction of the planned entry retaining roadway 9.

Further, as shown in fig. 13 and 16, the waste rock retaining and supporting device comprises telescopic U-shaped steel 11, a reinforcing mesh 16 and a metal mesh 10, wherein the two telescopic U-shaped steel 11 are fixed by overlapping through a flange 17 and are sequentially arranged at intervals along the moving direction of the roadway 9, the telescopic U-shaped steel 11 are connected on the flange 17 through a connecting rod 18, the reinforcing mesh 16 and the metal mesh 10 are sequentially hung on one side of the telescopic U-shaped steel 11 facing the goaf 15, and the reinforcing mesh 16 and the metal mesh 10 are overlapped and fixed by binding iron wires.

The waste rock blocking and supporting device is used for preventing waste rocks in the goaf 15 from drifting into the entry retaining roadway 9, the wire netting and the steel mesh 16 are bound together, the steel mesh 16 and the metal mesh 10 are overlapped, the overlapped part of the steel mesh 16 is overlapped by 100mm, the overlapped part of the metal mesh 10 is overlapped by 100mm, the steel wires are used for binding, and the waste rock blocking metal mesh 10 and the steel mesh 16 are fixed with the original roof wire netting structure in an overlapping mode. If serious gangue leakage occurs, a diamond-shaped metal net can be added in the reinforcing mesh 16 to strengthen gangue blocking support. The telescopic U-shaped steel 11 adopts an upper and a lower sections of contractible lap joint structure and is connected by two pairs of flanges 17. The telescopic U-shaped steel 11 is embedded below the bottom plate and is not less than 300mm, the usable connecting rods 18 and the flanges 17 of the adjacent telescopic U-shaped steel 11 are fixed to realize connection, the overall stability between the telescopic U-shaped steel 11 is reinforced, and the connecting rods 18 are determined to be long according to the size of the flanges 17 selected for purchase so as to increase the overall stability.

Further, the anti-roll device is a round steel 22, one end of the round steel 22 extends into the telescopic U-shaped steel 11 and is welded and fixed, and the other end of the round steel 22 is inserted into the kerf drilling hole 7. Round steel 22 can adopt the old and useless stock that the site operation left etc. can recycle the construction waste material, and the diameter of joint-cutting drilling 7 generally is 60cm moreover, and the diameter of round steel 22 has great choice space, can set up to diameter 30mm, and inserts joint-cutting drilling 7 about 200mm, specifically, welds the long round steel 22 of 400mm at the end of scalable U shaped steel 11, and the round steel 22 can adopt old and useless stock etc. leaks 200mm outward, inserts in joint-cutting drilling 7. When round steel 22 and the welding of scalable U shaped steel 11 upper portion, there is the inclination, the angle is the same with the lancing angle, and the same angle setting allows round steel 22's length to submerge the inside of lancing drilling 7 as far as possible, can provide more stable and deep protection basis for the motion that the roof probably takes place.

Further, as shown in fig. 16, the anti-trap device is a steel plate 27, and the steel plate 27 is horizontally welded to the lower portion of the telescopic U-shaped steel 11, and then the anti-trap device is embedded into the column socket on site. The purpose of embedding the column nest is to prevent two telescopic U-shaped steels 11 from being sunk into a coal seam of a bottom plate of a roadway retaining roadway 9 after being lapped. Specifically, the length, width and height of the steel plate 27 may preferably be 100mm × 100mm × 10mm, and the pre-excavation depth of the column nest may preferably be set to 300 mm.

In a preferred embodiment, as shown in fig. 13, the temporary lagging support device comprises five rows of single hydraulic prop 13 or portal supports, the lagging support distance is 250m, and when the goaf 15 is collapsed and compacted, namely the roadway is stabilized, the temporary lagging support device is withdrawn to the working face for circular support. The entry retaining roadway 9 is located in the working face hysteresis influence area 20, and in the area, because the rock caving of the top plate of the goaf 15 generates a certain friction effect on the top plate of the entry retaining roadway 9, the entry retaining roadway 9 is obviously influenced by dynamic pressure, and the pressure of the top plate is larger. Thus, the roof needs to be temporarily reinforced in the post-bay hysteresis zone 20. And the temporary support after the support is mainly delayed by adopting five rows of single hydraulic support columns 13 or door type supports matched with the hinged top beam 12.

As shown in fig. 13 and 14, in the planned entry retaining roadway 9 of the working face hysteresis influence area 20, the temporary hysteresis support device mainly adopts five rows of single hydraulic struts 13 matched with the hinged top beams 12 for hysteresis support. Wherein, the first, second, third, fourth and fifth rows of single hydraulic props 13 are respectively provided with a row of hinged top beams 12, and the hinged top beams 12 are arranged along the trend direction of the planned entry retaining roadway 9.

Further, as shown in fig. 17, the temporary lagging support device further includes a bottom beam 14, and the bottom beam 14 is laid along the running direction of the entry retaining roadway 9 and is padded at the bottom of the row of single hydraulic props 13 or the portal frames.

As shown in fig. 16, in order to control the floor heave of the planned entry retaining roadway 9, the drilling bottom of the single hydraulic prop 13 and the side inclination and the drilling bottom of the telescopic U-shaped steel 11 for waste rock blocking, the bottom beams 14 can be welded by using i-steel, two rows of single hydraulic props 13 at the auxiliary slope side of the entry retaining roadway 9 share one pair of T-shaped steel bottom beams 14 with the length of 2.1m, 3 rows of single hydraulic props 13 at the cutting seam side of the entry retaining roadway 9 share one pair of T-shaped steel bottom beams 14 with the length of 2.1m, the anti-sinking device is a steel plate 27 with the length, width and height of 100mm × 100mm × 10mm, the steel plate 27 and the lower part of the telescopic U-shaped steel 11 are horizontally welded, and then the anti-sinking device is buried into a 300mm column nest dug by a bottom plate on site, so as to prevent the two telescopic U-shaped steel 11 from sinking into the.

On the basis of the above embodiment, the row pitch of the single hydraulic prop 13 or the portal frame needs to be even times of the row pitch of the telescopic U-shaped steel 11, so that when the waste rock caving in the goaf 15 is not stable, the bottom beam 14 of the lagging support is used for abutting against the lower end of the telescopic U-shaped steel 11 of the waste rock support, and the waste rock blocking support can be prevented from toppling over.

For S500, as shown in fig. 18, after the working face mining is completed and the lane formation is stabilized, the temporary lagging support device in the lane keeping roadway 9 is removed, and the gob 15 is closed, and the lane keeping is completed.

The section of entry retaining roadway 9 is located in the working face entry stabilizing area 21, along with the continuous propulsion of the working face, when the entry retaining roadway 9 is far away from the working face, the collapse and compaction of the waste rock in the goaf 15 tend to be stable, at the moment, the entry retaining roadway 9 enters the entry stabilizing area 21, equipment for temporary support after erection can be withdrawn at intervals, only a waste rock retaining support device is reserved, and sealing materials are sprayed on one side, facing the goaf 15, of the waste rock retaining support device, so that the goaf 15 is sealed.

According to the technical scheme, the thick coal seam fully mechanized caving method for automatically forming the roadway along top tunneling, top cutting and pressure relief has the advantages and positive effects that: the method is suitable for planning entry retaining along the top plate tunneling of the mined coal seam during the fully mechanized top coal caving mining of the thick coal seam, and performing combined support on an beyond working face by using a temporary lag support device and a bottom beam, wherein the bottom beam is arranged along the trend direction of the entry retaining tunnel, so that the pressure of the temporary lag support device is uniformly dispersed onto a bottom plate coal seam of the entry retaining tunnel through the bottom beam, and the method can effectively prevent the situation that the temporary lag support is toppled or sunk into the bottom plate coal seam when the pressure is applied due to the fact that the bottom plate coal seam is soft, and reduce the problem of unstable support due to deformation of the bottom plate; and the anti-roll device, the anti-sinking device and the waste rock blocking support device are fixed, and the waste rock blocking support device and the anti-sinking device are embedded into the coal seam of the roadway retaining roadway bottom plate together, so that the reinforcing support anchor cable, the anti-roll device, the anti-sinking device and the waste rock blocking support device realize the mutual restraining and supporting effects on the roadway retaining roadway bottom plate and the pre-crack, the stability of the top plate in the collapse motion process is effectively improved, and the stability of the roadway retaining roadway when the next working face is reused is improved.

It is noted that, in this document, relational terms such as "first" and "second," and the like, may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

The foregoing are merely exemplary embodiments of the present invention, which enable those skilled in the art to understand or practice the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.