Grouting horizon and opportunity discrimination method for artificial consolidation body

Abstract

The invention discloses an artificial consolidation body grouting layer position and opportunity judgment method which comprises the steps that according to shallow-burial-depth fully-mechanized caving mining parameters, the theoretically-calculated artificial consolidation body grouting layer position is obtained; the grouting horizon and the earliest grouting opportunity of the artificial consolidation body are obtained by utilizing the measured data of overlying strata movement; determining the latest grouting opportunity of the artificial consolidation body by utilizing the actual measurement data of surface subsidence; computer numerical simulation is utilized to establish an evolution model of the artificial consolidation body for controlling the mining space void, and the optimal theoretical grouting opportunity and the theoretical grouting opportunity range of the artificial consolidation body with the largest mining space void are determined; and finally, actually measuring, checking, feeding back and adjusting the grouting opportunity, and checking, feeding back and obtaining the final grouting opportunity range of the artificial consolidation body by combining the actually-measured key rock stratum grouting amount, the grouting opportunity and the void ratio below the artificial consolidation body. According to the method, accurate control over the mining space of shallow-burial-depth fully-mechanized caving mining is achieved by accurately and reasonably judging the grouting layer position and the grouting opportunity of the artificial consolidation body.

Description

Technical Field

[0001] The present invention belongs to the technical field of coal mining, and is particularly applicable to mine scenarios such as solid waste disposal in shallow-buried coal mines, underground space utilization, green mining of mines, and filling mining. Specifically, it relates to a method for determining the grouting horizon and timing of artificial consolidated bodies. Background Art

[0003] As a reliable means and a green disposal method with low supervision costs, the filling technology is widely used by coal mining enterprises. This technology can scale up the treatment of solid waste and reduce the accumulation and emission of solid waste such as coal gangue. However, the western coal seams are characterized by shallow burial depth, large coal seam thickness, and fast mining speed. As the working face advances, the deformation speed of the shallow-buried mining space is fast, the deformation degree is large, and the mining volume is quickly transmitted to the ground surface, resulting in a fast closure of the mining space in shallow-buried fully-mechanized caving mining, a small filling space in the mining space, and a short filling timing, which restricts the efficient disposal of solid waste. The traditional filling method of gangue solid waste is difficult to meet the production and solid waste disposal requirements of modern large-scale mines, and the contradiction between high production and efficiency of coal mines and solid waste disposal is significant. Summary of the Invention

[0004] Aiming at the problem that the prior art cannot achieve high-volume and high-efficiency disposal without affecting production in the field of shallow-buried solid waste disposal, the present invention provides a method for determining the grouting horizon and timing of artificial consolidated bodies, which can determine the appropriate grouting horizon and timing of artificial consolidated bodies, so that the voids in the mining space are fully present to slow down their transmission to the ground surface, and solve the problems of many mining voids and fractures, easy caving, poor stability, difficult control of rock strata, and no solid waste filling disposal space and timing caused by shallow-buried fully-mechanized caving mining in the western mining area.

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

[0006] A method for determining the grouting horizon and timing of artificial consolidated bodies, the method comprising:

[0007] Obtaining shallow-buried fully-mechanized caving mining parameters;

[0008] According to the shallow-buried fully-mechanized caving mining parameters, obtaining the grouting horizon H of the theoretically calculated artificial consolidated body g ;

[0009] Using the measured data of overlying rock movement, obtaining the grouting horizon H of the artificial consolidated body s and the earliest grouting timing T min ;

[0010] Using the measured data of surface subsidence, determining the latest grouting timing T of the artificial consolidated body max ;

[0011] Use computer numerical simulation to establish an evolution model for artificial consolidated bodies to control the voids in the mined space, analyze the evolution law of the voids in the mined space at different grouting times of different artificial consolidated bodies, and determine the optimal theoretical grouting time T of the artificial consolidated body with the largest voids in the mined space r and the theoretical grouting time range T a ~T b ;

[0012] Finally, measure, check, feedback and adjust the grouting time. Combine the measured grouting volume, grouting time of the key strata and the void ratio under the artificial consolidated body to check and feedback to obtain the final grouting time range T am ~T bm 。

[0013] Preferably, the fully-mechanized caving mining parameters for shallow buried depth include the daily average advancing distance D e , coal seam thickness, mining and caving ratio, buried depth, working face length, physical and mechanical parameters of the coal seam and overlying rock mass

[0014] Preferably, according to the fully-mechanized caving mining parameters for shallow buried depth, obtain the grouting horizon H of the artificial consolidated body g including:

[0015] According to the fully-mechanized caving mining parameters for shallow buried depth, use the key stratum theory to obtain the breaking distances of different overlying strata horizons

[0016] According to the breaking distances of different overlying strata horizons, obtain the horizons of the key strata

[0017] According to the horizons of the key strata, obtain the grouting horizon H of the artificial consolidated body g 。

[0018] Preferably, the judgment of the grouting horizon H of the artificial consolidated body s is based on the range of the theoretically calculated grouting horizon H of the artificial consolidated body g , and through comparison and verification of the actual thickness, lithology and breaking law of the strata within the preset range obtained from the measured boreholes of overlying strata movement, obtain the actual grouting horizon H of the artificial consolidated body g 。 s 。

[0019] Preferably, the earliest grouting time T min is the distance D s when the designed grouting horizon H of the artificial consolidated body begins to break and deform as the working face advances min divided by the daily average advancing time D e , and the calculation formula is:

[0020] Preferably, the latest grouting time T of the artificial consolidated body maxThe distance D where there is no void in the mined space for surface subsidence to stabilize as the working face advances max Divided by the daily average advancing time D e , and the calculation formula is:

[0021] Preferably, use computer numerical simulation to establish an evolution model of artificial consolidated bodies controlling the voids in the mined space, analyze the evolution law of voids in the mined space at different grouting times of different artificial consolidated bodies, and determine the optimal theoretical grouting time T of the artificial consolidated body with the largest voids in the mined space r 、The theoretical grouting time range T a ~T b Includes:

[0022] Use discrete element software to establish an evolution model of artificial consolidated bodies controlling the voids in the mined space, obtain the cloud map of the evolution distribution law of voids in the key strata at different advancing distances, and use the binary method to obtain the void ratio of the key strata at different advancing distances;

[0023] According to the void ratio of the key strata at different advancing distances, conduct a simulation of the evolution of mined voids at different grouting times of different artificial consolidated bodies. Specifically: D min ~D max At intervals of the daily average advancing distance D e , simulate the advancement of D min 、D1、D2、D3……D x ……, when grouting the voids in the key strata to form artificial consolidated bodies, and then excavating to D max , obtain the evolution law of the voids under the artificial consolidated bodies after the voids in the key strata are filled with grout to form artificial consolidated bodies at different advancing distances after full excavation; According to the daily average advancing distance D e , obtain the evolution law of mined voids at different grouting times of different artificial consolidated bodies; among them, D min Is the distance when the key strata at the designed grouting horizon H s Of the working face start to break and deform; D max Is the distance where there is no void in the mined space for surface subsidence to stabilize as the working face advances; D1 is D min Plus 1 daily average advancing distance D e ; D x Is D min Plus x daily average advancing distances D e ;

[0024] Compare and analyze the laws of mined voids at different grouting times of different artificial consolidated bodies, and take the maximum value of the void ratio in the mined space as the optimal theoretical grouting time T r , and take the time range with a void ratio of 80% of the maximum value in the mined space as the theoretical grouting time range T of the artificial consolidated body a ~T b .

[0025] Preferably, D x is D min plus x Ds e , and the calculation formula is: D x = D min + xD e ; D min ≤ D x < D max , during simulation, after grouting to form an artificial key rock stratum when advancing to D x , further advance until reaching D max .

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

[0027] By accurately and reasonably judging the grouting horizon and grouting timing of the artificial consolidated body, the present invention realizes precise control of the mining space in shallow buried depth fully-mechanized caving mining, and realizes that the coal mining efficiency is not reduced as much as possible and the coal gangue and underground space are utilized to the greatest extent during the filling and disposal of solid wastes, thus facilitating the resource utilization of the mining space, the disposal of solid wastes and the green mining of coal mines.

[0028] The present invention can determine the appropriate grouting horizon and grouting timing of the artificial consolidated body, so that the voids in the mining space are fully present to slow down their transmission to the ground surface, and solves the problems existing in the western mining areas, such as many mining voids and fissures, easy caving, poor stability, difficult control of rock strata, and no space and timing for solid waste filling and disposal caused by fully-mechanized caving mining with shallow buried depth of rock strata.

[0029] The present invention has the advantages of improving the mechanical properties of surrounding rocks, saving the grouting volume, optimizing the grouting parameters, and improving the construction safety, etc. It not only improves the safety and economy of the project, but also improves the construction efficiency and quality. It has wide practicability in the technical field. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0031] Figure 1 is a flowchart of a method for discriminating the grouting horizon and timing of an artificial consolidated body of the present invention;

[0032] Figure 2 is a measured law diagram of overlying strata movement in shallow buried depth fully-mechanized caving mining of the present invention;

[0033] Figure 3 is a measured diagram of surface subsidence law in shallow buried depth fully-mechanized caving mining of the present invention;

[0034] Figure 4 This is the key stratum void distribution map at different advancing distances in the fully-mechanized caving mining with shallow burial depth of the present invention;

[0035] Figure 5 This is the schematic diagram of the grouting horizon and timing of the artificial consolidated body in the fully-mechanized caving mining with shallow burial depth of the present invention;

[0036] In the figure: 1 - Grouting horizon of the artificial consolidated body, 2 - Grouting timing of the artificial consolidated body, 3 - Void distribution in the mined space below the artificial consolidated body. Specific implementation manners

[0037] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0038] To make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific implementation manners.

[0039] Embodiment 1

[0040] The present invention provides a method for determining the grouting horizon and timing of an artificial consolidated body, as Figure 1 shown, including the following steps:

[0041] S1: Conduct on-site research to obtain the fully-mechanized caving mining parameters with shallow burial depth;

[0042] S2: Perform theoretical calculations, use the key stratum theory to obtain the fracture distances of different overlying strata, obtain the horizons of the key strata, and obtain the grouting horizon H of the theoretically calculated artificial consolidated body g ;

[0043] S3: Analyze the measured parameters of overlying strata movement, the overlying strata subsidence and fracture laws at different advancing distances, and obtain the grouting horizon H s and the earliest grouting timing T min ;

[0044] S4: Analyze the measured parameters of surface subsidence, the surface subsidence laws at different advancing distances, and determine the latest grouting timing T max ;

[0045] S5: Numerical simulation of the void evolution of key strata at different advancing distances. Use discrete element software to establish an evolution model of the voids in the mining space controlled by artificial consolidated bodies, obtain the contour map of the void evolution distribution of key strata at different advancing distances, and use the binary method to obtain the void ratios of key strata at different advancing distances;

[0046] Among them, obtaining the void ratios of key strata at different advancing distances by the binary method includes: through the software MATLAB, import the simulated pictures into the software, set different extreme values, change the simulated result pictures into black-and-white pictures, and in MATLAB, call the calculation function to obtain the void ratios.

[0047] S6: Numerical simulation of the void evolution during mining with different grouting times of artificial consolidated bodies, D min ~D max with the daily average advancing distance D e as the interval, simulate the advancement of D min , D1, D2, D3... D x ..., when grout the voids of the key strata to form artificial consolidated bodies, and then excavate to D max , obtain the void evolution law under the artificial consolidated bodies after the voids of the key strata are filled with grout at different advancing distances after full excavation; according to the daily average advancing distance D e , obtain the void evolution law during mining with different grouting times of artificial consolidated bodies. Among them, D min is the distance when the working face advances to the designed grouting horizon H s of the artificial consolidated body and starts to break and deform (the distance from the overlying strata movement monitoring borehole to the position of the working face when the grouting horizon H s starts to break and deform); D max is the distance when the working face advances to the mining space where the surface subsidence is stable and there are no voids to be filled (the distance from the working face when the surface subsidence is stable); D1 is D min plus 1 daily average advancing distance D e ; D x is D min plus x daily average advancing distances D e ; The evolution law is obtained by the simulation software through simulating different excavation distances.

[0048] S7: Determination of the theoretical grouting time range of artificial consolidated bodies. Compare and analyze the void laws during mining with different grouting times of artificial consolidated bodies, and take the maximum void ratio in the mining space as the best theoretical grouting time T r , and take the time range with a void ratio of 80% of the maximum void ratio in the mining space as the theoretical grouting time range T a ~T b ;

[0049] S8: Measure and check to feedback and adjust the grouting timing, measure the grouting volume, grouting timing of the key strata, and the void ratio under the artificial consolidated body, and feedback and adjust the grouting timing of the artificial consolidated body for fully-mechanized caving mining with shallow burial depth.

[0050] In this embodiment, the parameters of fully-mechanized caving mining with shallow burial depth in S1 include the daily average advancing distance D e , coal seam thickness, mining and caving ratio, burial depth, working face length, and physical and mechanical parameters of the coal seam and overlying rock mass.

[0051] In this embodiment, the judgment of the grouting horizon H s of the artificial consolidated body in S2 is based on the theoretical calculation of the range of the grouting horizon H g of the artificial consolidated body, and through the comparison and verification of the actual thickness, lithology, and fracture law of the strata obtained by the overburden movement measurement boreholes, the actual grouting horizon H g of the artificial consolidated body is obtained. s .

[0052] In this embodiment, the earliest grouting timing T min in S3 is the distance D s when the designed grouting horizon H min of the artificial consolidated body starts to fracture and deform as the working face advances, divided by the daily average advancing time D e , as shown in Equation 1:

[0053]

[0054] In this embodiment, the latest grouting timing T max of the artificial consolidated body in S4 is the distance D max when the surface subsidence is stable and there is no void to fill in the mined-out space as the working face advances, divided by the daily average advancing time D e , as shown in Equation 2:

[0055]

[0056] In this embodiment, D x in S6 is D min plus x times D e , as shown in Equation 3:

[0057] D x = D min + xD e (3)

[0058] In this embodiment, D x , D min ≤ D x < D max , during simulation, when advancing to D xAfter grouting to form an artificial key stratum, further advance until reaching D. max 。

[0059] In this embodiment, in S8, the grouting timing of the shallow-buried fully-mechanized caving artificial consolidation body is feedback-adjusted. Based on the comparison between the measured grouting volume of the key stratum, the grouting timing, and the void ratio data below the artificial consolidation body and the simulated key stratum void ratio and the void ratio below the artificial consolidation body, if the deviation from the simulated value is greater than 30%, then update the S5 simulation parameters with the actual void ratio parameters as the target, and repeat the steps from S5 to S8 until the deviation between the actual measurement value and the simulated value is less than or equal to 30%. Then, select the theoretical grouting timing range T a ~T b as the reasonable and effective optimal grouting timing range T of the artificial consolidation body. am ~T bm 。

[0060] Specific case

[0061] Taking a fully-mechanized caving coal mine in the western region as an example, the specific implementation steps are as follows:

[0062] S1: Conduct on-site research to obtain the parameters of shallow-buried fully-mechanized caving mining; according to the research, the coal seam burial depth of a fully-mechanized caving coal mine in the western region is 259 - 284 m, the coal seam thickness is 9 m, the mining-to-caving ratio is 1:0.621, the daily advance distance D e is 10 m, the length of a certain working face is 300 m, and the physical and mechanical parameters of the coal seam and overlying rock mass are shown in Table 1.

[0063] Table 1 Physical and mechanical parameters of the coal seam and overlying rock mass (comprehensive columnar diagram)

[0064]

[0065] S2: Theoretical calculation, using the key stratum theory to obtain the fracture distances of different overlying strata positions, obtain the positions of the key strata, and obtain the grouting layer position H of the theoretically calculated artificial consolidation body g ;

[0066] The key stratum is the stratum in the overlying strata of the stope that controls the movement of local or all strata up to the ground surface. If the first stratum is the first key stratum and its control range reaches the nth stratum, then the conditions that the (n + 1)th stratum must satisfy to become the second key stratum are:

[0067] (q n+1 )1 < (q n )1 (4)

[0068]

[0069] In the formula: q n+1The load formed by the (n + 1)-th layer of rock strata on the first layer of hard rock strata; q n The load formed by the n-th layer of rock strata on the first layer of hard rock strata; h i and γ i and E i are respectively the thickness, volume force, and elastic modulus of the i-th layer of rock strata (i = 1, 2,..., n).

[0070] Substituting the above parameters into Equation (4) and Equation (5), it is obtained that the hard rock strata meeting the criterion is the siltstone at a buried depth of 161 m and a thickness of 35 m in the 5th layer, which is the key rock strata H g is 161 m.

[0071] S3: Analysis of the measured parameters of overlying strata movement. Measuring boreholes are drilled above the ground surface of this working face, and fiber optic cables are implanted through the boreholes to realize the strain monitoring of the surrounding rock. When the measuring boreholes are drilled, it is measured that the siltstone of this key rock strata is located at a buried depth of 135.5 m and a thickness of 20.5 m, and it is obtained that H s is 135.5 m; further analyze the law of overlying strata subsidence and fracture under different advancing distances, as Figure 2 shown. When the working face advances 11.7 m past the monitoring borehole, slight strain changes occur in the lower part of the fiber optic cable, mainly tensile strain. When it passes 19.0 m past the borehole, the fiber optic cable breaks for the first time, and the fracture depth is about 162 m. When it advances 59.0 m past the monitoring borehole, the fiber optic cable in the borehole breaks again at a buried depth of 124 m, that is, at a buried depth of 124 m; when it advances 59.0 m past the monitoring borehole, the key rock strata begins to fracture, and the artificial consolidated body fissures initially form a mined-out space. It is obtained that as the working face advances, the distance D s when the artificial consolidated body design grouting horizon H min begins to fracture and deform is 59.0 m. Combining with Equation 1, the earliest grouting opportunity T min is 5.9 days

[0072] S4: Analysis of the measured parameters of surface subsidence. As Figure 3 shown, the subsidence law of the surface subsidence measurement points near the measured points of overlying strata movement. When the working face advances 700 m, the surface subsidence speed approaches stability. It is determined that the distance D max when the surface subsidence is stable and there is no void to fill in the mined-out space as the working face advances is 700 m. Combining with Equation 2, the latest grouting opportunity T max of the artificial consolidated body is obtained as 70 days.

[0073] S5: Numerical simulation of the void evolution of the key rock strata at different advancing distances. Use the discrete element software 3DEC to establish an evolution model of the void of the artificial consolidated body controlling the mined-out space, and simulate to obtain the contour map of the void evolution distribution law of the key rock strata at different advancing distances. Use the binary method to obtain the void ratio of the key rock strata at different advancing distances, as Figure 4 shown.

[0074] S6: Numerical simulation of the evolution of mining-induced voids at different grouting times for artificial consolidation bodies, D min ~D max That is, the average daily advancement distance D between 59m and 700m e The simulation advances 59, 69, 79, 89, ... 699 m at intervals of 10 m, and grouting is performed in the key rock strata to form an artificial consolidation body. max At 700m, the evolution law of the voids under the artificial consolidation body after the key rock strata voids were filled with grouting at different advancement distances after full excavation was obtained. With the increase of the grouting time of the artificial consolidation layer, the voids under the artificial consolidation body first increased rapidly and then decreased slowly; according to the average daily advancement distance of 10m, the evolution law of the mining-induced voids at different grouting times of the artificial consolidation body was obtained;

[0075] S7: The theoretical grouting timing range of artificial consolidation body is determined, and the mining void law of different artificial consolidation body grouting timing is compared and analyzed. When the artificial consolidation body grouting advances 200m, that is, 20 days behind the working face, the mining space void ratio is the maximum, so the optimal theoretical grouting timing T r For 20 days, Figure 5 As shown in the figure (1 is the grouting layer of the artificial consolidation body, 2 is the grouting time of the artificial consolidation body, and 3 is the distribution of the voids in the mining space below the artificial consolidation body), the time range when the void ratio of the mining space reaches 80% is taken as the theoretical grouting time range T of the artificial consolidation body. a ~T b , that is, 18 to 30 days;

[0076] S8: Adjust the timing of grouting by actual measurement, verification and feedback. The grouting amount, grouting timing and void ratio under the artificial consolidation body of key rock formations were measured. The void ratio under the artificial consolidation body of shallow-buried and fully-mechanized top coal caving mining was fed back by three-dimensional seismic exploration. The monitoring results showed that grouting was performed 18 days after the working face. The deviation between the actual value and the simulation value was 25%, which met the requirements. The optimal grouting timing of shallow-buried and fully-mechanized top coal caving artificial consolidation body T am ~T bm It takes 18 to 30 days.

[0077] The embodiments described above are only descriptions of the preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for determining the grouting horizon and timing of an artificial consolidated body, characterized in that, The method includes: Obtaining the parameters of fully-mechanized caving mining with shallow burial depth; According to the parameters of fully-mechanized caving mining with shallow burial depth, the grouting horizon H of the artificially consolidated body obtained by theoretical calculation g ; Using the measured data of overburden movement, obtain the grouting horizon H of the artificial consolidated body s and the earliest grouting opportunity T min ; Determine the latest grouting time T of the artificial consolidation body by using the measured data of surface subsidence max ; An evolution model for controlling the voids in the mining space by artificial consolidated bodies is established using computer numerical simulation to analyze the evolution law of the voids in the mining space at different grouting times of different artificial consolidated bodies, and to determine the optimal theoretical grouting time T of the artificial consolidated body with the largest voids in the mining space r , the theoretical grouting time range T a ~T b ; Finally, through on-site measurement, checking, feedback, and adjustment of the grouting timing, combined with the measured grouting volume of the key strata, the grouting timing, and the void ratio under the artificial consolidated body, the final grouting timing range T of the artificial consolidated body is obtained through checking and feedback am ~T bm 。 2. The method according to claim 1, wherein The parameters of fully-mechanized caving mining with shallow burial depth include the daily average advancing distance D e , coal seam thickness, mining and caving ratio, burial depth, face length, and physical and mechanical parameters of coal seam and overlying rock mass.

3. The method according to claim 1, wherein According to the fully-mechanized caving mining parameters with shallow buried depth, the grouting horizon H of the artificial consolidated body is obtained g Including: According to the parameters of fully-mechanized caving mining with shallow burial depth, using the key stratum theory to obtain the breaking distances of different overlying strata positions; According to the breaking distances of different overlying strata positions, obtaining the positions of the key strata; According to the horizon of the key strata, the grouting horizon H of the artificial consolidated body is obtained g .

4. The method according to claim 1, wherein Grouting horizon H of the artificial consolidated body s The determination of g the grouting horizon H of the artificial consolidated body is based on the theoretically calculated range of g H, and is obtained by comparing and verifying the actual thickness, lithology and fracture law of the rock strata within the preset range through the measured boreholes of overlying strata movement, so as to obtain the actual grouting horizon H of the artificial consolidated body s .

5. The method according to claim 1, wherein The earliest grouting time T min is the designed grouting horizon H of the artificial consolidated body as the working face advances s The distance D at the start of fracture deformation min divided by the average daily advance time D e , and the calculation formula is:

6. The method according to claim 1, characterized in that The latest grouting timing T of the artificial consolidated body max is the distance D where there is no void to fill in the mined-out space with stable surface subsidence as the working face advances max divided by the daily average advancing time D e , and the calculation formula is:

7. The method according to claim 1, wherein Establish an evolution model of the mined-out space voids controlled by artificial consolidated bodies using computer numerical simulation, analyze the evolution law of the mined-out space voids with different grouting timings of artificial consolidated bodies, and determine the optimal theoretical grouting timing T of the artificial consolidated body with the largest mined-out space voids r , the theoretical grouting timing range T a ~T b including: Using discrete element software to establish an evolution model of artificial consolidated bodies controlling the voids in the mining space, obtaining the contour map of the void evolution distribution law of the key strata at different advancing distances, and using the binary method to obtain the void ratios of the key strata at different advancing distances; According to the void ratios of the key strata at different advancing distances, simulate the evolution of mined-out voids during the grouting of different artificial consolidated bodies at different times. Specifically: D min ~D max At intervals of the daily average advancing distance D e simulate the advancement of D min , D1, D2, D3... D x ..., when grouting the voids of the key strata to form artificial consolidated bodies, and then excavating to D max , obtain the evolution law of the voids under the artificial consolidated bodies after the voids of the key strata at different advancing distances are filled with grout to form artificial consolidated bodies after sufficient excavation; according to the daily average advancing distance D e , obtain the evolution law of mined-out voids during the grouting of different artificial consolidated bodies at different times; among them, D min is the distance when the working face advances to the designed grouting horizon H s of the artificial consolidated body and starts to break and deform; D max is the distance when the working face advances and the mined-out space for surface subsidence stabilization has no voids to be filled; D1 is D min plus one daily average advancing distance D e ; D x is D min plus x daily average advancing distances D e ; Compare and analyze the law of mined voids at different grouting times of different artificial consolidated bodies, and take the maximum value of the mined space void ratio as the optimal theoretical grouting time T r , and take the time range with a maximum mined space void ratio of 80% as the theoretical grouting time range T of the artificial consolidated body a ~T b .

8. The method according to claim 7, wherein D x is D min plus x Ds e , and the calculation formula is: D x = D min + xD e ; D min ≤ D x < D max , during simulation, after grouting to form an artificial key stratum when advancing to D x , further advance until reaching D max .

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