A method for controlling mining space deformation through grouting and backfilling in shallow-buried fully mechanized longwall mining.

Abstract

This invention belongs to the field of backfilling mining and discloses a method for controlling the deformation of the mining space through grouting and backfilling in shallow-buried fully mechanized longwall mining. The method includes dividing the mining space into a main control auxiliary backfilling space and an auxiliary control main backfilling space, with double-hole grouting and backfilling boreholes spaced at intervals on the ground. The main control auxiliary backfilling space is filled with high-strength rapid-setting material and fly ash-based reinforcement material. These two materials bond with the fractured rock mass to form a cemented composite support structure, hindering the movement of the key strata and extending the existence time of the auxiliary control main backfilling space. The auxiliary control main backfilling space is filled with coal gangue slurry, supporting the cemented composite support structure and assisting in controlling the key strata. The two spaces work together to achieve high-volume solid waste disposal and surface subsidence protection in shallow-buried fully mechanized longwall mining. This method provides safe and reliable control of the mining space and, while controlling the mining space, can further control surface subsidence and protect water resources, achieving green and low-carbon goals. It has broad applicability in shallow-buried fully mechanized longwall backfilling and solid waste disposal.

Description

Technical Field

[0001] This invention belongs to the field of backfilling mining, and is particularly applicable to mining scenarios such as coal mine solid waste disposal, green mining, surface subsidence control, and water-conserving coal mining under shallow-buried and high-intensity mining conditions. Specifically, it relates to a method for controlling mining space deformation by grouting and backfilling in shallow-buried fully mechanized longwall mining. Background Technology

[0002] Energy security and environmental protection in western China have become an important part of green mine construction. However, western coal seams are characterized by shallow burial, large thickness, and fast mining speed. The rapid change in mining space due to shallow burial depth restricts the efficient disposal of gangue. Traditional gangue solid waste disposal methods are difficult to meet the production and solid waste disposal needs of modern large-scale mines.

[0003] Traditional delamination grouting and backfilling lacks delamination space under shallow fully mechanized longwall mining conditions; underground solid backfilling lacks backfilling space under shallow coal seam conditions; subsequent backfilling under shallow-deep fully mechanized longwall mining conditions results in rapid closure of the mining space, limiting the amount and timing of solid waste disposal, and even leading to hazards such as surface grouting. Therefore, a mining space control method is urgently needed for backfilling in shallow-deep fully mechanized longwall mining. This method should achieve solid waste disposal and surface subsidence protection through mining space control without affecting normal production at the working face. It should be simple to operate, safe and reliable, and have extremely high engineering application value. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides a method for controlling the deformation of the mining space through grouting and backfilling in shallow-buried fully mechanized longwall mining. By using different backfilling materials in the main control auxiliary backfilling space and the auxiliary control main backfilling space, the deformation of the key layer is controlled in a coordinated manner. This method provides a safe and reliable control effect on the mining space. While achieving mining space control, it can also further control green and low-carbon goals such as surface subsidence and water resource protection. It has wide applicability in shallow-buried fully mechanized longwall backfilling and solid waste disposal.

[0005] To achieve the above objectives, the present invention provides the following solution:

[0006] A method for controlling mining space deformation through grouting and backfilling in shallow-buried, deep-long fully mechanized longwall mining, the method comprising:

[0007] The mining space is divided into a main control auxiliary filling space and an auxiliary control main filling space. Double-hole grouting filling boreholes are arranged at intervals on the ground. Different filling materials are used in the two spaces to synergistically control the deformation of the mining space, achieving high-volume disposal of solid waste from shallow-buried fully mechanized mining. The main control auxiliary filling space is filled with high-strength quick-setting material and fly ash-based reinforcement material. The two materials bond with the fractured rock mass to form a cemented composite support body, which hinders the movement of the key layer and extends the auxiliary control main filling space. The auxiliary control main filling space is filled with coal gangue slurry to support the cemented composite support body and synergistically assist in controlling the key layer.

[0008] Preferably, the main control and auxiliary filling space is the space between the key layer above the caving zone and below, which restricts 60% to 80% of the movement of the mining space and fills it with 20% to 30% of fly ash solid waste.

[0009] Preferably, the auxiliary control main filling space is the caving zone space, which restricts the movement of 20% to 40% or more of the mining space and handles 70% to 80% of the coal gangue solid waste.

[0010] This invention also provides a method for controlling mining space deformation through grouting and backfilling in shallow-buried, deep-long fully mechanized longwall mining, the method comprising:

[0011] S1: Drill a borehole on the ground at the exploration borehole point, one square meter from the lead-in borehole in the advancing direction and in the middle of the working face in the perpendicular advancing direction; arrange two main exploration boreholes adjacent to the exploration borehole point. K t1 Auxiliary control exploration hole K t2 ,in, K t1 final borehole depth H t1 Located below the critical layer, at the top of the main control and auxiliary filling space; K t2 final borehole depth H t2 Located at the top of the auxiliary control and main charging space, above the landslide zone;

[0012] S2: Main control probe K t1 Auxiliary control exploration hole K t2 Water injection and pressure maintenance were carried out, and the progress of the main control exploration hole at the working face was recorded. K t1 When the injection pressure continues to decrease T t1 And the corresponding lag working face distance S t1 Auxiliary control exploration hole K t2 When the injection pressure continues to decrease T t2And the corresponding lag working face distance S t2 The spacing of the grouting and filling boreholes is given. D t ;

[0013] S3: Grouting begins in the exploratory borehole; timing is controlled by the main exploratory borehole. K t1 Auxiliary control exploration hole K t2 In respectively T t1 , T t2 Grouting begins at this time, with the main control borehole drilled in space. K t1 Auxiliary control drilling K t2 At the lagging working face S t1 S t2 Grouting begins at this location;

[0014] S4: The orifice pressure of the main control hole is greater than the maximum grouting pressure. P zmax The orifice pressure of the auxiliary control hole is greater than P fmax Stop grouting at that time;

[0015] S5: Before mining the working face, grouting and filling boreholes are arranged on the ground, with the arrangement points advancing in the same direction as the borehole spacing. D t Arranged sequentially, with the main control boreholes located in the middle of the working face in the vertical advancement direction; each arrangement point has two adjacent main control boreholes. K za Auxiliary control drilling K fa ,in, K za final borehole depth H za Located below the critical layer, at the top of the main control and auxiliary filling space; K fa final borehole depth H fa Located at the top of the auxiliary control and main charging space, above the landslide zone;

[0016] S6: Two drilling master control drilling K za Auxiliary control drilling K fa Perform water injection and pressure maintenance, and record the main control drilling progress of the working face. K za When the injection pressure continues to decrease T za And the corresponding lag working face distance S zaAssisted drilling K fa When the injection pressure continues to decrease T fa And the corresponding lag working face distance S fa ;

[0017] S7: Grouting begins at the grouting hole; timing is controlled by the main drilling. K za Auxiliary control drilling K fa In respectively T za , T fa Grouting begins at this time, with the main control borehole drilled in space. K za Auxiliary control drilling K fa At the lagging working face S za S fa Grouting begins at this location;

[0018] S8: Circulating grouting. Different grouting points are arranged in a cyclical manner as the working face advances, until the grouting of the working face is completed.

[0019] Preferably, in step S2, the spacing between the grouting and filling borehole arrangement points... D t According to the master drilling K z Lagging working face distance S z Subtract auxiliary control drilling K f Lagging working face distance S f The grouting process begins at this point, and the calculation formula is as follows: .

[0020] Preferably, in step S3, grouting begins at the exploratory borehole, and the timing of the exploratory borehole is controlled by the main exploratory borehole. K t1 Auxiliary control exploration hole K t2 In respectively T t1 , T t2 Grouting begins at this time, with the main control borehole drilled in space. K t1 Auxiliary control drilling K t2 At the lagging working face S t1 S t2 Grouting begins at the following location:

[0021] S31: Cemented composite support structure construction, where the orifice pressure of the main control hole is less than 30% of the minimum orifice pressure of the main control hole.P zmin When high-strength, rapid-setting materials are used for grouting and filling, the rock mass is bonded and solidified to seal mining-induced fractures; when the orifice pressure of the main control borehole is greater than 30% of the minimum orifice pressure of the main control borehole... P zmin At the same time, fly ash-based reinforcement materials are used to solidify and support the key layer, and to co-treat fly ash solid waste.

[0022] S32: Auxiliary control main filling space grouting, auxiliary control hole injects coal gangue slurry;

[0023] Among them, minimum orifice pressure P zmin is: In the formula, H The za is the grouting layer for the main control hole. γ The overall density of the strata γ 1 represents the specific gravity of fly ash-based reinforcing materials.

[0024] Preferably, in step S4, the maximum orifice pressure of the main control hole... P The zmax target is to control the mining space; the maximum grouting pressure must be less than the grouting layer of the main control hole. H za and coal seam burial depth H Formation pressure between coal seams and the grouting layer of the main control borehole H za, coal seam burial depth H Coal and grouting layers of the main control borehole H Comprehensive proportion of strata above coal seams below za γ 2. Related, the calculation formula is: K is the safety factor of 1.1 to 1.3.

[0025] Preferably, in step S4, the minimum orifice pressure of the auxiliary control hole is... P fmin With the goal of coordinating the control of subsidence and fracture of the overlying key strata, the minimum grouting pressure needs to be greater than the self-weight of the overlying strata, and the grouting layer of the auxiliary control boreholes needs to be considered. H fa The above-mentioned comprehensive stratigraphic proportions γ 3. and the specific gravity of coal gangue slurry The relevant calculation formula is as follows: Maximum orifice pressure of auxiliary control hole P fmax It is 1.1 to 1.3 times the minimum orifice pressure.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] This invention utilizes different filling materials in the primary and secondary filling spaces to collaboratively control the fracture deformation of key layers. The mining space control effect is safe and reliable, the engineering construction is simple, and the operational indicators are clear. While achieving mining space control, it can further control green and low-carbon goals such as surface subsidence and water resource protection, demonstrating broad applicability in this technical field. Attached Figure Description

[0028] To more clearly illustrate the technical solution of the present invention, the drawings used in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a flowchart of a method for controlling the deformation of mining space by grouting and filling in shallow-buried deep fully mechanized longwall mining according to the present invention;

[0030] Figure 2 This is a cross-sectional view of the drilling layout for grouting and filling in shallow-buried fully mechanized longwall mining according to the present invention.

[0031] Figure 3 This is a plan view of the grouting and filling borehole layout for shallow-buried fully mechanized longwall mining according to the present invention;

[0032] In the diagram: 1-Main control auxiliary filling space, 2-Auxiliary control main filling space, 3-Key layer, 4-High-strength rapid-setting material, 5-Fly ash-based reinforcement material, 6-Cemented composite load-bearing body, 7-Coal gangue slurry, 8-Main control borehole (when it is an exploratory borehole, it is a main control exploratory borehole) K t1, when it is a grouting hole K za), 9-Auxiliary control borehole (when it is an exploratory borehole, it is an auxiliary control exploratory borehole) K t2, when it is a grouting hole K zb), 10-The burial depth of the main control borehole (when it is an exploratory borehole, it is the main control exploratory borehole). H t1, when it is a grouting hole H za), 11-the burial depth of the auxiliary borehole (when it is an exploratory borehole, it is an auxiliary control exploratory borehole) H t2, when it is a grouting hole H zb), 12-coal seam burial depth stratum H Coal, 13 - Main control exploration hole K t1, 14 - Auxiliary control exploration hole K t2, 15 - Main control drilling K za, 16-Auxiliary Control Drilling K fa, 17 - Length of the working face (square), 18 - Spacing between grouting and filling boreholes D t. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0035] Example 1

[0036] Taking a shallow-buried, fully mechanized longwall mining coal mine in western China as an example, the specific implementation steps are as follows:

[0037] This invention provides a method for controlling the deformation of the mining space through grouting and backfilling in shallow-buried, deep fully mechanized longwall mining. The mining space is divided into a main control auxiliary backfilling space 1 and an auxiliary control main backfilling space 2, as follows: Figure 2 , Figure 3 As shown, double-hole grouting and filling boreholes are arranged at intervals on the ground. Different filling materials are used in the two-layer space to control the deformation of the mining space in a coordinated manner, so as to achieve high-volume disposal of solid waste from shallow-buried deep fully mechanized mining.

[0038] In this embodiment, the main control auxiliary filling space 1 is the space between the key layer 3 above the caving zone and below, which restricts 60% to 80% of the movement of the mining space and fills it with 20% to 30% of fly ash solid waste.

[0039] In this embodiment, the auxiliary control main filling space 2 is the caving zone space, which restricts the movement of 20% to 40% or more of the mining space and handles 70% to 80% of the coal gangue solid waste.

[0040] In this embodiment, the main control auxiliary filling space 1 is filled with high-strength quick-setting material 4 and fly ash-based reinforcing material 5 through grouting. The two materials bond with the fractured rock mass to form a cemented composite bearing body 6, which hinders the movement of the key layer 3 and extends the auxiliary control main filling space 2.

[0041] In this embodiment, the auxiliary control main filling space 2 is filled with coal gangue slurry 7, which supports the cemented composite bearing body 6 and assists in the control of the key layer 3.

[0042] Furthermore, such as Figure 1 As shown, a method for controlling mining space deformation through grouting and backfilling in shallow-buried fully mechanized longwall mining includes the following steps:

[0043] S1: Exploration hole layout, drilling holes in the ground at the exploration borehole point, located one square meter ahead of the lead hole in the advancing direction. Figure 2Center 17 is located in the middle of the working face in the vertical advancement direction. Two main control exploration boreholes are arranged adjacent to the exploration borehole point. K t1 13. Auxiliary control exploration hole K t2 14. K t1 final borehole depth H t1 Located below the critical layer, at the top of the main control and auxiliary filling space; K t2 final borehole depth H t2 Located at the top of the secondary control and main filling space, above the caving zone.

[0044] S2: Water injection test of the exploration hole, main control exploration hole K t1 13. Auxiliary control exploration hole K t2 14. Perform water injection and pressure maintenance, and record the progress of the main control exploration hole at the working face. K t1 When to start when the water injection pressure of 13 continues to decrease T t1 And the corresponding lag working face distance S t1 Auxiliary control exploration hole K t2 14. Timing of initiation when the injection pressure continues to decrease T t2 And the corresponding lag working face distance S t2 The spacing between the grouting and filling boreholes is given. D t 18 that is Figure 2 18.

[0045] S3: Grouting begins in the exploratory borehole; timing is controlled by the main exploratory borehole. K t1 13. Auxiliary control exploration hole K t2 14 respectively in T t1 , T t2 Grouting begins at this time, with the main control borehole drilled in space. K t1 Auxiliary control drilling K t2 At the lagging working face S t1 S t2 Grouting begins at this location.

[0046] Specifically, S31: the cemented composite support 6 is constructed when the orifice pressure of the main control hole is less than 30% of the minimum orifice pressure of the main control hole. P zminAt that time, high-strength, rapid-setting material was used for grouting and filling to bond the rock mass and seal the mining-induced fractures; when the orifice pressure of the main control borehole was greater than 30% of the minimum orifice pressure of the main control borehole... P zmin At that time, fly ash-based reinforcement material 5 was used to solidify and support the key layer 3, and fly ash solid waste was disposed of in a coordinated manner.

[0047] Among them, the constructed cemented composite bearing body is a mixed rock mass formed by sealing and reinforcing the fractured rock mass in the main control and auxiliary filling space (the space between the key layer above the collapse zone and below the collapse zone) with high-strength quick-setting materials and fly ash-based materials. The bearing capacity, cohesion and tensile strength of the modified rock mass are better than those of the original fractured rock mass, so it is called cemented composite bearing body.

[0048] S32: Grouting of the auxiliary control main filling space 2, and injection of coal gangue slurry 7 into the auxiliary control hole. The grouting process involves preparing the slurry according to the designed ratio, and then injecting it into the auxiliary hole main filling space using a grouting pump. The grouting pressure is monitored at all times, and grouting closure measures are implemented after the borehole grouting is completed.

[0049] S4: Stop grouting; the orifice pressure of the main control hole is greater than the maximum grouting pressure. P zmax The orifice pressure of the auxiliary control hole is greater than P fmax Stop grouting at that time.

[0050] S5: Grouting and filling borehole layout. Grouting and filling boreholes are laid out on the ground before the working face is mined. The layout points are advanced in the direction of the borehole layout point spacing. D t Arranged sequentially, positioned in the middle of the working face in the vertical advancement direction. Two main control boreholes are arranged adjacent to each other at a single arrangement point. K za Auxiliary control drilling K fa . K za final borehole depth H za Located below the critical layer, at the top of the main control and auxiliary filling space; K fa final borehole depth H fa Located at the top of the secondary control and main filling space, above the caving zone.

[0051] S6: Water injection test parameter monitoring, two main control boreholes K za 15. Auxiliary control drilling K fa 16. Perform water injection and pressure maintenance, and record the progress of the main control borehole at the working face. K za When to start when the injection pressure of 15 continues to decreaseT za And the corresponding lag working face distance S za Assisted drilling K fa Timing of starting when the injection pressure of 16 continues to decrease T fa And the corresponding lag working face distance S fa .

[0052] S7: Grouting begins at the grouting hole; timing is controlled by the main drilling. K za 15. Auxiliary control drilling K fa 16 respectively in T za , T fa Grouting begins at this time, with controlled drilling in space. K za 15. Auxiliary control drilling K fa 16 respectively at the lagging working face S za S fa Grouting begins at this location.

[0053] Repeat steps S31 to S4. (The grouting process for the grouting holes is the same as that for the exploratory holes, except that the holes are given different names at different times depending on their functions.)

[0054] S8: Circulating grouting (in terms of time, the same hole, according to the change of function, is first an exploration hole (water injection and pressure maintenance), and then a grouting hole (slurry injection); in terms of space, the boundary is the influence of the working face advance. As the working face is mined, the pre-mining water injection and pressure maintenance hole is an exploration hole. After mining, due to the generation of fractures, the parameters monitored by the exploration hole are obtained, and the exploration hole becomes a grouting hole). Different grouting layout points are grouted in sequence as the working face advances until the grouting of the working face is completed.

[0055] In this embodiment, the spacing between the grouting and filling boreholes in S2 is... D t 18. Based on the master control drilling K z Lagging working face distance S z Subtract auxiliary control drilling K f Lagging working face distance S f Grouting begins at the location shown in equation (1).

[0056] (1)

[0057] In this embodiment, the minimum orifice pressure of the main control hole in S31 Pzmin With the goal of controlling the subsidence and fracture of the overlying key layer 3, the minimum grouting pressure needs to be greater than the self-weight of the overlying stratum and the grouting layer of the main control hole. H za The above-mentioned comprehensive stratigraphic proportions γ and the specific gravity of fly ash-based reinforcing material 5 γ 1. The relevant calculation is shown in Equation 2.

[0058] (2)

[0059] In this embodiment, the maximum grouting pressure mentioned in S4 includes the maximum orifice pressure of the main control hole. P zmax Maximum orifice pressure of auxiliary control hole P fmax .

[0060] Among them, the maximum orifice pressure of the main control hole P zmax With the goal of controlling the mining space, the maximum grouting pressure must be less than the grouting layer of the main control hole. H za With coal seam burial depth H 煤 The formation pressure between them, and the grouting layer of the main control borehole. H za Coal seam burial depth H 煤 and the grouting layer of the main control hole H za Overall proportion of strata above the following coal seams γ 2. Related calculations are shown in Equation 3.

[0061] (3)

[0062] Where K is a safety factor of 1.1~1.3, and the minimum orifice pressure of the auxiliary control hole. P fmin With the goal of coordinating the control of the subsidence and fracture of the overlying key layer 3, the minimum grouting pressure needs to be greater than the self-weight of the overlying overburden, and the grouting layer of the auxiliary control hole needs to be considered. H fa The above-mentioned comprehensive stratigraphic proportions γ 3 and the specific gravity of coal gangue slurry 7 The relevant calculations are shown in Equation 4.

[0063] (4)

[0064] Maximum orifice pressure of auxiliary control hole P fmax It is 1.1 to 1.3 times the minimum orifice pressure.

[0065] In this embodiment, the high-strength quick-setting material 4 is a water glass-cement two-component slurry, with a volume ratio of water glass to cement slurry of 0.6:1. The cement slurry comprises 70-90 parts cement and 100-120 parts water by mass.

[0066] In this embodiment, the fly ash-based reinforcing material 5 comprises, by weight, 40 parts fly ash, 25 parts cement, 3 parts quick-setting agent, and 32 parts water.

[0067] In this embodiment, the gangue slurry comprises, by mass fraction, 70 parts coal gangue aggregate and 30 parts water.

[0068] In this embodiment, the gangue slurry is characterized in that the particle size of the coal gangue aggregate is not higher than 20 mm.

[0069] In this technical solution, high-strength quick-setting material 4 and fly ash-based reinforcing material 5 are bonded to the fractured rock mass in the main control auxiliary filling space 1 to form a cemented composite bearing body 6, which hinders the movement of the key layer 3, extends the auxiliary control main filling space 2, and provides filling space and filling time for the auxiliary control main filling space 2. This is conducive to solving the problem of large-scale treatment of gangue in shallow-buried deep fully mechanized mining. Moreover, since the system is arranged on the ground, it does not affect the safe and efficient mining underground, and can achieve parallel mining and filling. This method is logically reasonable, highly applicable, simple to operate, and effective, and has a wide range of application value.

[0070] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made to the technical solutions of the present invention by those skilled in the art without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for controlling deformation of a mining space in shallow depth fully-mechanized caving and grouting filling, characterized in that, The method comprises: S1: probing drilling point ground punching, one square in the direction of advancement in the advanced cut, in the middle of the working face vertically in the direction of advancement; probing drilling point adjacent arrangement of two drilling main control probing holes K t1 , auxiliary control probing holes K t2 , wherein K t1 the depth of the final hole horizon H t1 is located in the lower part of the key layer and the top of the main control auxiliary space K t2 the depth of the final hole horizon H t2 is located in the upper part of the caving zone and the top of the auxiliary control main space S2: master control probe hole K t1 , auxiliary control probe hole K t2 Carrying out water injection pressure maintenance, recording the working face advancing master control probe hole K t1 The starting time when the water injection pressure of the master control probe hole T t1 and the corresponding lag working face distance S t1 , auxiliary control probe hole K t2 The starting time when the water injection pressure of the auxiliary control probe hole T t2 and the corresponding lag working face distance S t2 , give the grouting filling drill hole arrangement point spacing D t ; S3: start grouting in the exploration hole, and the main control exploration hole is in time K t1 , the auxiliary control exploration hole K t2 start grouting at T t1 , T t2 , the main control drilling hole is in space K t1 , the auxiliary control drilling hole K t2 start grouting at the lagging working face S t1 , S t2 ; specifically comprising: S31: cemented composite carrier construction, when the orifice pressure of the main control hole is less than 30% of the minimum orifice pressure of the main control hole P zmin , adopt high-strength rapid-setting material grouting filling, bonding rock mass solidification to seal mining fissures; when the orifice pressure of the main control hole is greater than 30% of the minimum orifice pressure of the main control hole P zmin , adopt fly ash-based reinforcement material to solidify the key layer and cooperatively dispose fly ash solid waste; S32: auxiliary control main filling space grouting, auxiliary control hole injection coal gangue slurry; wherein the minimum orifice pressure P zmin is: wherein, H za is the main control hole grouting horizon, γ is the comprehensive formation specific gravity, γ 1 is the specific gravity of fly ash-based reinforcing material; S4: the orifice pressure of the master control hole is greater than the maximum grouting pressure P zmax the orifice pressure of the auxiliary control hole is greater than P fmax the grouting is stopped; S5: ground layout of grouting filling drill hole before working face mining, two drill holes are laid out in each layout point according to drill hole layout point spacing in point pushing direction D t are laid out in turn and located in the middle of working face in vertical pushing direction; two drill holes are laid out in adjacent single layout point K za , auxiliary control drill hole K fa , wherein K za the buried depth of the final hole layer of H za is located in the lower part of the key layer and the top of the main control auxiliary filling space K fa the buried depth of the final hole layer of H fa is located in the upper part of the caving zone and the top of the auxiliary control main filling space S6: two main control boreholes K za , auxiliary control borehole K fa Water injection pressure is maintained, and the working face advancing main control borehole K za The starting time when the water injection pressure continues to decrease T za And the corresponding lag working face distance S za , auxiliary control borehole K fa The starting time when the water injection pressure continues to decrease T fa And the corresponding lag working face distance S fa ; S7: grouting hole starts grouting, time main control drilling K za , auxiliary control drilling K fa starts grouting respectively at T za , T fa , spatial main control drilling K za , auxiliary control drilling K fa starts grouting respectively at lagging working face S za , S fa ; S8: circulating grouting, different grouting arrangement points, with the working face advancing, the grouting process is sequentially and circularly carried out until the working face grouting is completed.

2. The method of claim 1, wherein, The S2, grouting filling drilling arrangement point interval D t According to the master control drilling K z The lag working face distance S z Subtract the auxiliary control drilling K f The lag working face distance S f Start grouting at, the calculation formula is: .

3. The method of claim 1, wherein, In the S4, the maximum orifice pressure of the main control hole P zmax The maximum grouting pressure should be less than the grouting layer of the main control hole H za The stratum pressure between the coal seam buried depth H 煤 The grouting layer of the main control hole H za The coal seam buried depth H 煤 The grouting layer of the main control hole H za The comprehensive specific gravity of the stratum above the following coal seam γ 2 related, the calculation formula is: K is the safety factor 1.1~1.

3.

4. The method of claim 1, wherein, The minimum orifice pressure of the auxiliary control hole in S4 P fmin In order to cooperatively control the sinking breakage of the overlying key layer, the minimum grouting pressure needs to be greater than the self weight of the overlying strata, and the auxiliary control hole grouting horizon H fa The above comprehensive specific gravity of strata γ 3 and the specific gravity of coal gangue slurry Related, the calculation formula is: The maximum orifice pressure of the auxiliary control hole P fmax 1.1~1.3 times of the minimum orifice pressure.

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