Mining method for reducing losses by controlling the collapse of rock mass in goaf roof

Abstract

The present invention discloses a method for mining with reduced losses by regulating and controlling the expansion of collapsed rock mass in a goaf, which belongs to the field of coal mining technology. The method includes: obtaining an optimal regulation scheme by simulation based on the basic mining data of the mine, wherein the optimal regulation scheme includes the loading strength, loading times and loading stress path of the hydraulic support, and the conditions of the optimal scheme are maximizing the expansion height of the collapsed rock mass of the roof and minimizing the surface subsidence; regulating the hydraulic support during the advancement of the working face according to the optimal regulation scheme; monitoring data during the advancement of the working face, integrating and analyzing the monitoring data, and selecting the optimal regulation scheme for continued execution or adjustment based on the integrated analysis results. Through the above technical solution, the present invention effectively increases the degree of expansion and expands the scope of expansion.

Description

Technical Field

[0001] The present invention belongs to the technical field of coal mining, and in particular relates to a mining method for reducing losses by regulating and controlling the collapse of rock mass in a goaf roof. Background Art

[0002] Reducing roof damage during coal mining, controlling surface deformation, and protecting the ecological environment are among the key scientific and technological challenges currently faced. Improving roof collapse and expansion in goafs during mining plays a key role in achieving this goal. The 110 / N00 method, based on roof cutting and expansion filling, employs roof slitting technology, fully utilizing the discontinuity and anisotropy of the rock mass. This allows the goaf roof to fully collapse and expand under the action of mining pressure, reducing concentrated stresses and significantly improving roof stability. Surface deformation at the slits is now within a controllable range.

[0003] However, this method still has certain limitations. It is effective only at the cut seam, while the degree of expansion gradually decreases in the middle of the working face, resulting in failure to meet higher requirements for roof control and surface protection. In this context, expanding the scope of roof expansion at the working face has become a top research priority. Therefore, there is an urgent need for the development of mining methods that can control and reduce losses by expanding the rock mass expansion of the collapsed roof in the goaf. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention proposes a method for mining by regulating and reducing losses by controlling the collapse of the rock mass in the goaf roof, so as to solve the problems existing in the above-mentioned prior art.

[0005] To achieve the above-mentioned object, the present invention provides a method for mining by controlling the loss reduction of rock mass by roof collapse in goaf, comprising:

[0006] Based on the mine's basic mining data, simulations were conducted to determine the optimal control scheme, which included the hydraulic support's loading strength, loading times, and loading stress path. The optimal control scheme was based on maximizing the height of the roof collapse rock mass and minimizing the ground subsidence.

[0007] According to the optimal control scheme, the hydraulic support is controlled during the advancement of the working face;

[0008] Monitor the monitoring data during the working face advancement process, including the surface deformation curve, the height of the collapsed rock mass, and the pressure and displacement change curve of the hydraulic support column;

[0009] Conduct an integrated analysis of the monitoring data, and based on the results of the integrated analysis, continue to implement or adjust the optimal control plan.

[0010] Optionally, before obtaining the loading strength of the hydraulic support, the average working resistance and additional working resistance of the hydraulic support are calculated based on basic mining data, and the support selection resistance is calculated based on the average working resistance and additional working resistance as the maximum limit of the loading strength of the hydraulic support.

[0011] Optionally, the process of obtaining the optimal control solution includes:

[0012] According to the basic mining data of the mine, a calculation model is constructed based on the discrete element model, wherein the calculation model includes a simulation numerical model of the goaf and a mathematical calculation model based on numerical simulation or theoretical calculation;

[0013] The simulation numerical model is simulated and calculated with different loading intensities, loading times and loading stress paths through a mathematical calculation model to obtain the roof expansion height and the surface subsidence. The loading intensity, loading times and loading stress path with the maximum roof expansion height and the minimum surface subsidence are used as the optimization control scheme.

[0014] Optionally, coal is mined through the working face mining control process during the advancement of the working face, wherein the working face mining control process includes: cutting coal, moving the comprehensive mining hydraulic support, and moving the front scraper conveyor, wherein the moving comprehensive mining hydraulic support is moved according to the loading intensity, loading times and loading stress path according to the optimal control plan.

[0015] Optionally, the process of monitoring the monitoring data during the working face advancement process includes:

[0016] Surface deformation, crushing height, and hydraulic support column pressure and displacement changes

[0017] Set a surface deformation monitoring point on the surface in the middle of the working face and obtain the surface deformation curve of the surface deformation monitoring point;

[0018] Drilling inclined holes from the two lanes of the goaf behind the working face to the middle of the working face to obtain the height of the roof of the working face;

[0019] Pressure sensors and displacement sensors are set in the columns and jacks of the hydraulic support, and the column pressure curve and displacement change curve are collected by the pressure sensors and displacement sensors.

[0020] Optionally, the process of integrating and analyzing monitoring data includes:

[0021] Determine whether the monitoring data meets the control requirements, wherein a threshold judgment is performed on the monitoring data, and whether the control requirements are met is determined based on the threshold judgment result.

[0022] Optionally, the process of continuing to execute or adjusting the optimal control solution includes:

[0023] When the surface deformation curve and crushing height meet the control requirements, the optimal control plan will continue to be implemented;

[0024] When the surface deformation curve and crushing expansion height do not meet the control requirements, it is determined whether the column pressure and displacement change curves meet the control requirements;

[0025] When the column pressure and displacement change curves do not meet the control requirements, the execution of the optimal control plan and the hydraulic support are checked;

[0026] When the column pressure and displacement change curves meet the control requirements, the optimal control scheme is adjusted or redesigned.

[0027] Compared with the prior art, the present invention has the following advantages and technical effects:

[0028] 1. The use of support resistance control can effectively promote the pre-crushing of the roof rock within a certain range, thereby further improving the degree of rock collapse and expansion in the goaf and reducing the sinking space after the overlying rock strata are broken;

[0029] 2. Reduce the amount of basic roof subsidence in the direction of working face advancement, weaken the phenomenon of high-position roof separation, slow down the variation of the maximum principal stress of the overlying rock strata, reduce the basic roof stress concentration coefficient, and ensure safe production of the working face;

[0030] 3. Dynamic regulation of the support and roof can expand the scope of expansion and crushing, reduce surface settlement, protect surface buildings, reduce ecological damage, and achieve source prevention and control of ecological damage in mining areas. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of this application. The exemplary embodiments and descriptions of this application are intended to explain this application and do not constitute an improper limitation on this application. In the accompanying drawings:

[0032] Figure 1 This is a design flow chart of a method for mining with controlled loss reduction due to collapse of rock mass in a goaf roof according to an embodiment of the present invention;

[0033] Figure 2 Schematic diagram of support control in a method for controlling loss reduction in mining by controlling rock mass expansion and roof collapse in a goaf according to an embodiment of the present invention;

[0034] Figure 3 Schematic diagram of a method for mining with controlled loss reduction due to collapse of rock mass in a goaf roof according to an embodiment of the present invention;

[0035] Figure 4 The simulated support resistance curve of an embodiment of the present invention;

[0036] Figure 5This is a comparison cloud diagram of the simulated crushing expansion before and after regulation of the stent according to an embodiment of the present invention. DETAILED DESCRIPTION

[0037] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0038] It should be noted that the steps shown in the flowcharts of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and that, although a logical order is shown in the flowcharts, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0039] The purpose of this invention is to provide a method for mining in which the rock mass collapses and expands during roof collapse in goaf areas, thereby reducing losses. This method not only effectively increases the degree of collapse and expands the scope of collapse, but also provides a new technical approach for controlling the roof and protecting the ground surface. To achieve the above objectives, the technical solutions adopted are as follows:

[0040] The method for controlling and reducing the loss of mining by controlling the collapse of the rock mass in the goaf includes the following steps:

[0041] Step 1: Collect basic mining data such as geological conditions of the working face and operating procedures, and calculate the average working resistance P of the hydraulic support through theoretical calculation. 工 , the additional resistance is at least 1.5 times the average working resistance, that is, P 额 >=1.5*P 工 , so the resistance of bracket selection is calculated to be the sum of working resistance and additional resistance;

[0042] Among them, an information collection module and a variable pressure safety valve are installed on the hydraulic support of the working face. The hydraulic support is equipped with columns and jacks. The information collection module includes pressure sensors and displacement sensors arranged in the columns and jacks, which can monitor the force and displacement changes of the support in real time.

[0043] Among them, the working resistance is calculated by multiplying the support area and the support strength, among which the support strength is related to factors such as the coal seam mining height, the roof rock density, and the dynamic load coefficient. The support strength is determined based on basic mining data such as the geological conditions of the working face and the operating procedures. The support area is determined based on the support top control distance and the support center distance. The support area is determined based on the layout of the hydraulic support in the basic mining data.

[0044] Step 2: Taking the support selection resistance as the maximum limit of loading strength, determine the control schemes such as the support loading strength P, loading times N, and loading stress path L on the roof in sequence to ensure that the roof is fully crushed and the impact on coal mining efficiency is reduced. Specifically, the following steps are included:

[0045] Step 2A: Based on the collected geological conditions and operating procedures of the working face, a calculation model is established through numerical simulation or theoretical calculation;

[0046] Among them, the PFC numerical model can be selected to simulate the collected working face geological conditions and operating procedures. In the PFC numerical model, a simulation numerical model is constructed according to the working face geological conditions, and the simulation numerical model is gradually adjusted according to the operating procedures. A calculation model for the simulation numerical model is established through the Mohr-Coulomb model in the PFC software;

[0047] Step 2B: Determine the loading intensity research plan based on the selected support resistance, and ultimately obtain the optimal control plan for the loading intensity P, loading number N, and loading stress path L through numerical simulation or theoretical calculation;

[0048] Among them, a hydraulic support simulation model is set up in the simulation numerical model, and the loading intensity is used as the applied load of the above simulation numerical model. The simulation is carried out through the calculation model to obtain the roof crushing height and surface subsidence in the simulated working face geology. The support selection resistance is used as the maximum limit of the loading intensity. By adjusting the loading intensity, loading times and loading stress path differently, the roof crushing height is maximized and the surface subsidence is minimized. Among them, the specific judgment of the target is made by artificial experience or weighted sum to obtain the optimal control plan.

[0049] Step 3: Determine the working face mining control process based on the parameters in the above optimal control scheme. The fully mechanized working face mines coal according to the process of cutting coal, moving the fully mechanized hydraulic support, and moving the front scraper conveyor. Every time the working face advances Lm, the support after the support is moved applies a load of strength P to the roof in turn, and then unloads it. This cycle is repeated N times. Coal mining and control are coordinated with each other to reduce interference between the two.

[0050] Step 4: Real-time monitoring of ground deformation, crushing height, and column pressure changes during the working face advancement process, specifically including the following steps:

[0051] Step 4A: Set up a surface deformation monitoring point on the surface in the middle of the working face, and derive the surface deformation curve every day to analyze whether the control requirements are met;

[0052] Among them, relevant thresholds are set for the maximum value and average value of the surface deformation curve to determine whether they exceed the threshold. If they exceed the threshold, they do not meet the control requirements.

[0053] Step 4B: Drill inclined holes from the two lanes in the goaf behind the working face toward the middle of the working face to analyze the height of the roof expansion of the working face;

[0054] Among them, relevant thresholds are set for the maximum and average values ​​of the height of the roof expansion of the working face to determine whether they exceed the thresholds. If they exceed the thresholds, they do not meet the control requirements.

[0055] Step 4C: Derive the support column pressure and displacement change curve every day to analyze whether the loading intensity, loading times and loading stress path of the above scheme are achieved;

[0056] The pressure and displacement change curve of the bracket column determines the pressure data and displacement change data. According to the preset loading intensity and loading stress path, it is judged whether the error of each corresponding data each time is within the controllable threshold. If not, it does not meet the control requirements.

[0057] Step 5: Integrate and analyze the above monitoring data to determine whether the control requirements are met, and then decide whether to redesign the control plan. The specific steps include:

[0058] Step 5A: Determine whether the surface deformation and crushing height meet the control requirements. If so, continue to use the current control plan.

[0059] Step 5B: If the ground deformation and crushing height do not meet the control requirements, analyze the column pressure and displacement change curves to determine whether the support is operating according to the designed loading intensity, loading times and loading stress path. If the column pressure and displacement curves do not match the design plan, check the actual operation and equipment for problems such as faults;

[0060] Step 5C: If the column pressure curve is consistent with the design plan, readjust the calculation model parameters according to the current design plan and the ground deformation and crushing height, and redesign the control plan.

[0061] The purpose of the present invention is to provide a method for mining with reduced losses due to collapse of the roof of the goaf. The design flow chart is as follows: Figure 1 As shown, the support resistance is used to apply cyclic load to the top plate, which effectively promotes direct top pre-crushing. The schematic diagram of the support control is shown in Figure 2 As shown in the figure, it not only improves the collapse and expansion degree of the non-cut side and middle roof of the working face, but also expands the expansion range. The schematic diagram of the dynamic control method of the support is shown in the figure. Figure 3 As shown, it is a completely new technical path for controlling the roof and protecting the surface.

[0062] The above technical solution is explained in detail through relevant examples and actual data:

[0063] The designed production capacity of a mine in a certain mining area is 6.50Mt / a. The main coal seam currently mined is 2# coal. The designed first mining working face is 201 working face. The working face advancement length is 800m, the face length is 100m, the burial depth is 200m, the coal seam thickness is 3-4m, and the average thickness is 3.5m. The 110 working method is used for mining, and the daily advance is 8.0m / d. There are buildings left on the surface, which belongs to the three-down pressure coal. The surface subsidence control range is required to be within 0.1m, so the surface control requirements are relatively high.

[0064] S1. Collect basic mining data such as geological conditions, operating procedures, and histograms of the 201 working face, and calculate the average working resistance P of the hydraulic support through theoretical calculation. 工 The load is 10,000 kN, and the additional resistance is at least 1.5 times the average working resistance, that is, P rated >= 1.5*P work, and 15,000 kN is selected. Therefore, the support selection resistance P is calculated to be the sum of the working resistance and the additional resistance, that is, P = 25,000 kN; wherein, an information acquisition module and a variable pressure safety valve are installed on the hydraulic support on the working surface. The information acquisition module includes pressure sensors and displacement sensors in the columns and jacks, which can monitor the force and displacement changes of the support in real time;

[0065] S2. Determine the control schemes such as the support loading strength P, loading times N, and loading stress path L on the roof in sequence to ensure that the roof is fully crushed and expanded and the impact on coal mining efficiency is reduced, specifically including the following steps:

[0066] S2A. Based on the collected geological conditions and operating procedures of the working face, a calculation model was established through numerical simulation methods. A PFC numerical model with a size of 500m×150m was established. The coal seam was buried at a depth of 200m. A uniformly distributed load of 2.5MPa was applied vertically downward to the top of the model. The horizontal displacement was constrained on both sides of the model, and the vertical displacement was constrained at the bottom. The Mohr-Coulomb model was used to simulate the rock layer structure, and the gravity field was set to 9.8m / s. 2 , the structural unit model is used to simulate the hydraulic support;

[0067] S2B. Determine the loading strength research plan based on the selected support resistance. Study the roof plate crushing height and surface subsidence when the support loading strength is 15,000 kN, 20,000 kN, and 25,000 kN respectively. With the goal of maximizing the roof plate collapse rock mass crushing height and minimizing the surface subsidence, select the optimal loading strength and then study the roof plate crushing height and surface subsidence when the loading times are 1, 2, and 3. Finally, study the roof plate crushing height and surface subsidence when the advancement step distance is 1m, 2m, 3m, 4m, and 5m respectively.

[0068] According to the simulation results, the optimal loading intensity P, loading times N and loading stress path L are 20,000 kN, 2 times and 5 m respectively. The support resistance curve is as follows: Figure 4As shown, the comparison cloud diagram of simulated expansion before and after stent regulation is as follows Figure 5 shown.

[0069] The ultimate goal of the above simulation is to minimize surface subsidence. While maximizing the roof heave height is a prerequisite for this, it is not an absolutely necessary and sufficient condition and may be affected by other special circumstances. Based on this, surface subsidence can be used as the ultimate goal, or, while maximizing the roof heave height, the minimum surface subsidence can be considered, i.e., the weighted sum of the target values ​​can be used for calculation.

[0070] S3. Determine the working face mining control process based on the above parameters. The fully mechanized mining working face mines coal according to the process of cutting coal, moving the fully mechanized hydraulic support, and moving the front scraper conveyor. Every time the working face advances 5 meters, the support after the support is moved applies a load of 20,000 kN to the roof, then unloads it. This cycle is repeated twice. Coal mining and control are coordinated to reduce interference between the two.

[0071] S4. Real-time monitoring of ground deformation, crushing height, and column pressure changes during the working face advancement process, specifically including the following steps:

[0072] S4A: Set up surface deformation monitoring points on the ground in the middle of the working face. The working face advances 800m, with a monitoring point set every 5m. A total of 160 monitoring points are set up. Surface deformation curves are derived daily to analyze whether control requirements are met.

[0073] S4B: Drill inclined holes from the two lanes in the goaf behind the working face toward the middle of the working face for observation. Drill holes every 50m and record and analyze the height of the roof expansion at the working face.

[0074] S4C: Derive the pressure and displacement curves of the support columns every day to analyze whether the loading intensity, loading times, and loading stress path of the above scheme are achieved;

[0075] S5. After practical application, it was detected that the surface subsidence was controlled within 0.1m, so there was no need to adjust the control plan. It also proved that this method can effectively control the surface and protect the ecological environment.

[0076] The above are merely preferred embodiments of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A method for reducing losses by regulating and controlling the collapse of the rock mass in the goaf roof, characterized in that: include: Based on the mine's basic mining data, simulations were conducted to determine the optimal control scheme, which included the hydraulic support's loading strength, loading times, and loading stress path. The optimal control scheme was based on maximizing the height of the roof collapse rock mass and minimizing the ground subsidence. According to the optimal control scheme, the hydraulic support is controlled during the advancement of the working face; Monitor the monitoring data during the working face advancement process, including the surface deformation curve, the height of the collapsed rock mass, and the pressure and displacement change curve of the hydraulic support column; Conduct integrated analysis of monitoring data and, based on the results of the integrated analysis, continue to implement or adjust the optimal control plan; The process of obtaining the optimal control plan includes: According to the basic mining data of the mine, a calculation model is constructed based on discrete element simulation, wherein the calculation model includes a simulation numerical model of the goaf and a mathematical calculation model based on numerical simulation or theoretical calculation; The simulation numerical model is simulated and calculated with different loading intensities, loading times and loading stress paths through a mathematical calculation model to obtain the roof expansion height and the surface subsidence. The loading intensity, loading times and loading stress path with the maximum roof expansion height and the minimum surface subsidence are used as the optimization control scheme.

2. The method according to claim 1, characterized in that Before obtaining the loading strength of the hydraulic support, the average working resistance and additional working resistance of the hydraulic support are calculated based on basic mining data. Based on the average working resistance and additional working resistance, the support selection resistance is calculated as the maximum limit of the loading strength of the hydraulic support.

3. The method according to claim 1, characterized in that During the advancement of the working face, coal is mined through the working face mining control process, which includes: cutting coal, moving the fully-mechanized mining hydraulic support, and moving the front scraper conveyor. The fully-mechanized mining hydraulic support is moved according to the loading intensity, loading times and loading stress path of the optimal control scheme.

4. The method according to claim 1, wherein The process of monitoring the monitoring data during the working face advancement includes: Monitor ground deformation, crushing height, and hydraulic support column pressure and displacement changes; Set a surface deformation monitoring point on the surface in the middle of the working face and obtain the surface deformation curve of the surface deformation monitoring point; Drilling inclined holes from the two lanes of the goaf behind the working face to the middle of the working face to obtain the height of the roof of the working face; Pressure sensors and displacement sensors are set in the columns and jacks of the hydraulic support, and the column pressure curve and displacement change curve are collected by the pressure sensors and displacement sensors.

5. The method according to claim 1, wherein The process of integrating and analyzing monitoring data includes: Determine whether the monitoring data meets the control requirements, wherein a threshold judgment is performed on the monitoring data, and whether the control requirements are met is determined based on the threshold judgment result.

6. The method according to claim 5, characterized in that The process of continuing to implement or adjusting the optimal control plan includes: When the surface deformation curve and crushing height meet the control requirements, the optimal control plan will continue to be implemented; When the surface deformation curve and crushing expansion height do not meet the control requirements, it is determined whether the column pressure and displacement change curves meet the control requirements; When the column pressure and displacement change curves do not meet the control requirements, the execution of the optimal control plan and the hydraulic support are checked; When the column pressure and displacement change curves meet the control requirements, the optimal control scheme is adjusted or redesigned.

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