Goaf roof caving rock mass breaking and expanding regulation and damage reduction mining method

Abstract

The invention discloses a goaf roof caving rock mass breakage and expansion regulation and damage reduction mining method, which belongs to the technical field of coal mining, and comprises the following steps: according to basic mining data of a mine, carrying out analogue simulation to obtain an optimal regulation scheme which comprises the loading strength, loading frequency and loading stress path of a hydraulic support; the conditions of the optimal scheme are as follows: the crushing and expanding height of the roof caving rock mass is maximized and the surface subsidence is minimized; the hydraulic support is regulated and controlled in the working face advancing process according to the optimal regulation and control scheme; monitoring data in the advancing process of the working face are monitored, the monitoring data are subjected to integrated analysis, and the optimal regulation and control scheme is selected to continue to be executed or adjusted based on the integrated analysis result. According to the technical scheme, the crushing and expanding degree is effectively increased, and the crushing and expanding range is expanded.

Description

Technical Field

[0001] The invention belongs to the technical field of coal mining, and in particular relates to a method for mining with reduced loss caused by the collapse of roof of a goaf area and rock mass expansion and fragmentation. Background Art

[0002] Reducing roof disasters in the working face during coal resource mining, controlling surface deformation, and protecting the ecological environment are one of the key scientific and technological problems currently faced. Improving the roof expansion of the goaf during mining plays a key role in achieving this goal. The 110 / N00 method based on top cutting and expansion filling adopts the roof cutting technology, making full use of the discontinuity and anisotropy of the rock mass, so that the roof of the goaf can fully collapse and expand under the action of the mine pressure, reducing the concentrated stress, greatly improving the stability of the roof, and the surface deformation at the cutting is within a controllable range.

[0003] However, the above method still has certain limitations. This method has a good expansion effect only at the cutting joint, while the expansion degree in the middle of the working face gradually weakens, resulting in the failure to meet higher requirements for roof control and surface protection. In this context, expanding the expansion range of the working face roof has become a top priority for research and development. Therefore, there is an urgent need for the emergence of a method for reducing the loss of mining by controlling the expansion of the rock mass in the collapsed roof of 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 the loss of rock mass by collapse of the roof of the goaf, so as to solve the problems existing in the above prior art.

[0005] To achieve the above-mentioned purpose, the present invention provides a method for mining by regulating and reducing the loss of rock mass expansion and roof collapse in goaf areas, comprising:

[0006] According to the basic mining data of the mine, the optimal control scheme is obtained through simulation, which includes the loading strength, loading times and loading stress path of the hydraulic support. The conditions of the optimal control scheme are to maximize the height of the roof collapse rock mass and minimize the surface 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 advancement of the working face, including the surface deformation curve, the height of the collapsed rock mass, and the column pressure and displacement change curve of the hydraulic support;

[0009] Conduct an integrated analysis of the monitoring data and, based on the results of the integrated analysis, choose to continue executing 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 the 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 a 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] Through the mathematical calculation model, the simulation numerical model is simulated and calculated with different loading intensities, loading times and loading stress paths to obtain the roof expansion height and the ground subsidence. The loading intensity, loading times and loading stress path with the maximum roof expansion height and the minimum ground subsidence are used as the optimization control scheme.

[0014] Optionally, coal mining is carried out 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 of the comprehensive mining hydraulic support is carried out according to the optimal control plan to perform loading intensity, loading times and loading stress path.

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

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

[0017] A surface deformation monitoring point is set on the surface in the middle of the working face to obtain a surface deformation curve of the surface deformation monitoring point;

[0018] Drill 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 arranged in the columns and jacks of the hydraulic support, and the pressure curve of the column and the displacement change curve are acquired by the pressure sensors and the 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 scheme 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 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 scheme 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 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 area and reducing the sinking space after the overlying rock strata are broken;

[0029] 2. Reduce the amount of basic roof subsidence in the advancing direction of the working face, weaken the delamination phenomenon of the high-position roof, slow down the change range of the maximum principal stress of the overlying rock formation, reduce the basic top stress concentration coefficient, and ensure safe production of the working face;

[0030] 3. Dynamic regulation of the support-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 drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

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

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

[0034] Figure 3 It is a schematic diagram of a method for mining by controlling the loss reduction of rock mass expansion and roof collapse in a goaf area according to an embodiment of the present invention;

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

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

[0037] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present 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 the present invention is to provide a method for mining with reduced losses by controlling the expansion of rock mass in the collapsed roof of the goaf, which not only effectively increases the expansion degree and expands the expansion range, but also is a new technical path for controlling the roof and protecting the surface. To achieve the above purpose, the technical scheme adopted is as follows:

[0040] The method for mining with controlled loss reduction of rock mass expansion and roof collapse in goaf area 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 bracket selection resistance is calculated to be the sum of the working resistance and the 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 provided 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, wherein the support strength is related to factors such as coal seam mining height, roof rock density, dynamic load coefficient, etc. The support strength is determined according to basic mining data such as working face geological conditions and operating procedures. The support area is determined according to the support top control distance and the support center distance. The support area is determined according to 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 turn to ensure that the roof is fully crushed and the impact on coal mining efficiency is reduced, which specifically includes the following steps:

[0045] Step 2A: Establish a calculation model through numerical simulation or theoretical calculation based on the collected geological conditions and operation procedures of the working face;

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

[0047] Step 2B, determine the loading strength research plan according to the selected support resistance, and finally obtain the optimal control plan of loading strength P, loading number N and loading stress path L through numerical simulation or theoretical calculation;

[0048] 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 the 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. Specifically, the target is judged by artificial experience or weighted sum to obtain the optimal control plan.

[0049] Step 3: Determine the working face mining control process according to 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. When the working face advances Lm, the rear support of the moving support applies a load of strength P to the roof in turn, and then unloads it. The load is applied N times in a cycle. 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 advancement of the working face, including the following steps:

[0051] Step 4A: Set 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 and average values ​​of the surface deformation curve to determine whether they exceed the thresholds. If they exceed the thresholds, they do not meet the control requirements.

[0053] Step 4B: drill inclined holes from the two lanes of the goaf behind the working face to 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 pressure and displacement curve of the support column every day to analyze whether the loading intensity, loading times and loading stress path of the above scheme are achieved;

[0056] The support column pressure and displacement change curve 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, so as to decide whether to redesign the control plan, which specifically includes the following steps:

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

[0059] Step 5B: If the ground deformation and crushing height do not meet the control requirements, analyze the column pressure and displacement change curve to determine whether the support is operating according to the designed loading strength, loading times and loading stress path. If the column pressure and displacement curve does not conform to the design plan, check whether there are any problems such as actual operation and equipment failure.

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

[0061] The purpose of the present invention is to provide a method for mining with reduced losses due to collapse of the rock mass in the goaf roof. 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 support regulation is shown in Figure 2 As shown in the figure, it not only improves the collapse and expansion degree of the non-cutting 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 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. Currently, the main coal seam 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 method is used for mining, and the daily advance is 8.0m / d. There are buildings on the surface, which belongs to the third-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 bar charts 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; Among them, the information acquisition module and the variable pressure safety valve are installed on the hydraulic support of 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, sequentially determine the control schemes such as the loading strength P, the loading times N and the loading stress path L of the support on the roof to ensure that the roof is fully crushed and expanded and the impact on the coal mining efficiency is reduced, specifically including the following steps:

[0066] S2A. According to 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 uniform load of 2.5MPa was applied vertically downward on 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 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 according to the selected support resistance, and study the roof swell height and surface subsidence when the support loading strength is 15,000 kN, 20,000 kN, and 25,000 kN respectively. The goal is to maximize the roof collapse rock mass swell height and minimize the surface subsidence. After selecting the optimal loading strength, study the roof swell height and surface subsidence when the loading times are 1, 2, and 3 times. Finally, study the roof swell height and surface subsidence when the advancement step 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 in the figure, the simulated expansion comparison cloud map before and after the stent regulation is as follows Figure 5 shown.

[0069] The ultimate goal of the above simulation is to minimize the surface subsidence. The maximum height of the roof swell is a prerequisite for the minimum surface subsidence, but it is not an absolute necessary and sufficient condition, and may be affected by other special circumstances. On this basis, the surface subsidence can be taken as the ultimate goal, or the surface subsidence can be minimized when the roof swell height is the maximum, that is, the target values ​​are weighted and calculated.

[0070] S3. The mining and control process of the working face is determined according to the above parameters. 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. When the working face advances 5m, the rear support of the moving support applies a load of 20,000 kN to the roof in turn, and then unloads it. The cycle is repeated twice. Coal mining and control are coordinated with each other to reduce interference between the two.

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

[0072] S4A, set up surface deformation monitoring points on the surface in the middle of the working face. The working face advancement length is 800m, and a monitoring point is set every 5m. A total of 160 points are set up, and the surface deformation curve is derived every day to analyze whether the control requirements are met;

[0073] S4B, drill inclined holes from the two lanes of the goaf behind the working face to the middle of the working face for observation, observe once every 50m, and record and analyze the height of the roof expansion of the working face;

[0074] S4C, export 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. This also proved that this method can effectively control the surface and protect the ecological environment.

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

Claims

1. A method for reducing the loss of mining by regulating the collapse of the rock mass in the goaf roof, characterized in that: include: According to the basic mining data of the mine, the optimal control scheme is obtained through simulation, which includes the loading strength, loading times and loading stress path of the hydraulic support. The conditions of the optimal control scheme are to maximize the height of the roof collapse rock mass and minimize the surface 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 advancement of the working face, including the surface deformation curve, the height of the collapsed rock mass, and the column pressure and displacement change curve of the hydraulic support; Conduct an integrated analysis of the monitoring data and, based on the results of the integrated analysis, choose to continue executing or adjust the optimal control plan.

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

3. The method according to claim 1, characterized in that The process of obtaining the optimal control solution 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; Through the mathematical calculation model, the simulation numerical model is simulated and calculated with different loading intensities, loading times and loading stress paths to obtain the roof expansion height and the ground subsidence. The loading intensity, loading times and loading stress path with the maximum roof expansion height and the minimum ground subsidence are used as the optimization control scheme.

4. The method according to claim 1, characterized in that: During the advancement of the working face, coal mining is carried out through the working face mining control process, where the working face mining control process includes: cutting coal, moving the comprehensive mining hydraulic support, and moving the front scraper conveyor. The moving comprehensive mining hydraulic support is moved according to the optimal control plan to determine the loading intensity, loading times and loading stress path.

5. The method according to claim 1, characterized in that The process of monitoring the monitoring data during the advancement of the working face includes: Surface deformation, crushing height, and column pressure and displacement changes of hydraulic support A surface deformation monitoring point is set on the surface in the middle of the working face to obtain a surface deformation curve of the surface deformation monitoring point; Drill 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 arranged in the columns and jacks of the hydraulic support, and the pressure curve of the column and the displacement change curve are acquired by the pressure sensors and the displacement sensors.

6. The method according to claim 1, characterized in that 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.

7. The method according to claim 6, characterized in that The process of continuing to execute 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 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 scheme 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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