Mining ground fracture formation and development analysis method

Abstract

The invention provides a mining ground fracture formation and development analysis method. The mining ground fracture formation and development analysis method comprises the following steps: determining basic information of a coal face test sample; processing basic information of model construction and constructing a numerical simulation model; performing simulation excavation on the model and preliminarily monitoring the position where the mining ground fissures are generated; the initial model is excavated again, monitoring points are arranged around the position where the crack is pre-generated in detail, and stress and displacement before and after the mining ground crack is formed are monitored; excavation is continued, and stress and displacement in the mining ground fracture development and repair process are monitored; and carrying out induction processing on the monitoring data. According to the scheme, a numerical simulation method is adopted to predict the position and form of the mining ground fissures in advance, the advantage that numerical simulation can repeat coal seam excavation under the same geological condition is utilized, deformation and stress characteristics of the mining ground fissures in the forming and development process are analyzed, and under the condition that the actual geology is guaranteed, the mining ground fissures are accurately excavated. And the mechanical mechanism of formation and development of the mining ground fissures can be obtained through computer simulation.

Description

Technical Field

[0001] The invention relates to the technical field of coal mining subsidence, and in particular to a method for analyzing the formation and development of mining-induced ground fissures. Background Art

[0002] The geological characteristics of some coal mining areas are: shallow coal seams, thick coal seams, thin bedrock, and the surface is covered by thick loose layers. The mining practice of coal seams in such mining areas shows that high-intensity mining of thick coal seams leads to violent roof movement and mining pressure in the mining area, which can easily cause subsidence and damage of overlying rock layers and the surface, forming surface cracks of various forms and shapes, affecting the normal progress of coal production, and causing serious damage to the fragile ecological environment of the western mining areas.

[0003] Surface mining cracks are the intuitive manifestation of coal mining and rock movement on the surface. Their formation and development conditions are closely related to coal mining parameters, rock and soil layer distribution and physical and mechanical properties. At present, the research on the formation and development laws of mining ground cracks mainly includes theoretical analysis and similar simulation. Among them, the theoretical analysis method has made a lot of simplifications to the actual geological conditions of the project, so as to explain the causes of cracks using mechanical principles. For example, patent CN113006869B simplifies the loose layer into an arch beam structure, and predicts the generation of ground cracks based on the maximum tensile stress of its upper boundary and the ultimate tensile strength of the loose layer. This simplification cannot reflect the actual impact of the complex geological environment of the thick loose layer and has poor accuracy. Although similar simulation tests can reproduce the complex geological conditions of the mining area, the test process is complicated to operate, and the simulation results are heavily dependent on the ratio of similar materials, so the test results are difficult to be fully reproduced.

[0004] Therefore, the existing methods for analyzing the formation and development of mining-induced ground fissures have problems of poor accuracy or complex operation and need to be further optimized. Summary of the invention

[0005] The invention provides a method for analyzing the formation and development of ground fissures caused by mining, so as to solve the problems of poor accuracy or complex operation of the method for analyzing the formation and development of ground fissures caused by mining in the prior art.

[0006] In order to solve the above problems, the present invention provides a method for analyzing the formation and development of mining-induced ground fissures, comprising:

[0007] S10. Determine the basic information of the test sample of the coal mining face;

[0008] S20, processing basic information of model construction and constructing a numerical simulation model;

[0009] S30, simulating excavation of the model and preliminarily monitoring the locations of ground fissures caused by mining;

[0010] S40, re-excavating the initial model, arranging monitoring points around the locations where cracks are expected to be generated, and monitoring the stress and displacement before and after the formation of the mining-induced ground cracks;

[0011] S50. Continue excavation and monitor the development of ground fissures caused by mining and the stress and displacement during the repair process;

[0012] S60: Summarize and process the monitoring data.

[0013] Furthermore, S10 includes:

[0014] S11, select a coal mining face as the research object, arrange multiple drilling holes within the range of the face to obtain rock formation information and soil medium characteristics of the face to determine the initial structure of the stratum;

[0015] S12. Conduct mechanical parameter tests on rock and soil samples to obtain the strength, density, water content, Young's modulus, and Poisson's ratio parameters of each rock and soil layer.

[0016] Furthermore, S20 includes:

[0017] S21. Conduct preliminary modeling based on geological data and test data;

[0018] S22. Determine the stratigraphic division of the working face: divide the rock strata in the working face area into loose layer, bedrock layer, upper basic roof, lower basic roof, direct roof, coal seam, and floor rock layer from top to bottom.

[0019] Furthermore, in S21, subdivision layers are used in modeling, and multi-region block construction is carried out.

[0020] Further, S22 includes:

[0021] S221, simulate excavation of the coal seam of the built model, and as the working face advances, the roof rock layer collapses, and at this time, the thickness H5 of the collapsed rock layer is recorded, and this part of the rock layer is divided into a group, namely, the direct roof;

[0022] S222. Continue simulating excavation. With the continuous collapse of the direct roof, a rock layer of a certain thickness on the direct roof begins to break and collapse, and delamination cracks appear in the rock layer overlying the broken rock layer. At this time, the thickness H4 of the collapsed rock layer is recorded, and this part of the rock layer is divided into a group, namely, the lower basic roof; continue excavation, and the rock layer with cracks begins to break and collapse. The thickness H3 of this part of the rock layer is recorded, and this part of the rock layer is divided into a group, namely, the upper basic roof.

[0023] Furthermore, S22 also includes:

[0024] S223, dividing the rock layers between the loose layer and the basic top into one group, namely the bedrock layer, with a thickness of H2;

[0025] S224. The thicknesses of the loose layer, the coal seam and the bottom rock layer are represented by H1, H6 and H7 respectively.

[0026] Furthermore, S30 includes:

[0027] S31, adjusting the grouped models to a state where the coal seam is not excavated, and simulating excavation of the coal seam again, wherein the excavation progress is consistent with the actual work construction progress according to the set time ratio;

[0028] S32. As the working face continues to advance to a certain distance, the bedrock layer fractures and sinks, and mining-induced ground fissures are generated in the loose layer. The position coordinates, opening degree, size and spatial distribution characteristics of the mining-induced ground fissures are recorded, and the ground fissures are numbered and recorded.

[0029] Furthermore, S40 includes:

[0030] S411, vertical monitoring point arrangement: take the ground fissure occurrence point at the contact surface between the loose layer and the bedrock layer as the starting point of the ground fissure for monitoring point arrangement, arrange the monitoring points equidistantly upward from the starting point in the vertical direction, and arrange the monitoring points on the blocks on both sides of the ground fissure;

[0031] S412. Horizontal monitoring point arrangement: Arrange at equal distances on the same horizontal line of vertical monitoring points;

[0032] S421, stress monitoring: obtaining stress data in the x-direction, y-direction, and z-direction of each monitoring point;

[0033] S422, displacement monitoring: displacement is calculated based on the coordinate change between two monitoring points originally at the same level. The formula is as follows:

[0034] D=|X i动 ′-X i定 ∣=√(x i动 ′-x i定 ) 2 +(y i动 ′-y i定 ) 2 +(z i动 ′-z i定 ) 2 ,

[0035] Where D is the distance that the rock mass moves after the ground fissure is generated, X i动 ′ is the coordinate of the moving side of the ground fissure after the ground fissure is generated, X i定 The side coordinates that did not move after the ground fissure occurred.

[0036] Furthermore, S50 includes:

[0037] As the working face continues to advance, the first complete mining ground fissure is formed. Two main fissures are defined according to the advancing direction, namely F1 and F2. When the working face continues to advance for a distance, the ground fissure F2 closes, which is recorded as F2′, and the third main ground fissure F3 is formed; among them,

[0038] The monitoring process of the ground fissure F3 is consistent with the operation of steps S30 and S40, and its stress and displacement are monitored;

[0039] The ground fissure F2′ is monitored by continuing to use the ground fissure F2 monitoring point arrangement in S40.

[0040] Furthermore, S60 includes:

[0041] S61. List and analyze the data at the ground fissures F1 and F2 obtained when the ground fissures caused by mining are formed for the first time, and explore the mechanical mechanism of the formation of ground fissures caused by mining;

[0042] S62, comparative analysis and processing of the data at the ground fissures F2 and F2′ from the formation to the restoration, to explore the restoration mechanism of the ground fissures;

[0043] S63. Comprehensively analyze the data obtained from the ground fissure F3 and the data in S61 to explore the differences and connections between the development and formation mechanical mechanisms of ground fissures.

[0044] This scheme uses numerical simulation methods to analyze the formation and development of mining-induced ground fissures. Under the condition of ensuring the actual geology, the process of mining-induced ground fissures formation can be obtained through computer simulation, and the numerical simulation method can accurately restore the mining phenomenon under the same model. For the formation mechanism of mining-induced ground fissures, the location and shape of mining-induced ground fissures can be predicted in advance with the help of numerical simulation methods. The advantage of numerical simulation that coal seam excavation under the same geological conditions can be repeated. The shape and location of ground fissures can be known in advance through the first simulation, and then measurement points are arranged in advance near the pre-excavated ground fissures on the unexcavated model to monitor and analyze the formation mechanical mechanism of ground fissures. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0046] Figure 1 A flow chart of the method for analyzing the formation and development of mining-induced ground fissures provided by the present invention;

[0047] Figure 2A schematic diagram of the loose layer stratification and block modeling in the mining-induced ground fissure formation and development analysis method provided by the present invention;

[0048] Figure 3 A schematic diagram of stratum division in the method for analyzing the formation and development of mining-induced ground fissures provided by the invention;

[0049] Figure 4 A schematic diagram of the evolution process of mining-induced ground fissures in the mining-induced ground fissure formation and development analysis method provided by the invention;

[0050] Figure 5 A schematic diagram of the arrangement of monitoring points for stress and displacement of mining-induced ground fissures in the method for analyzing the formation and development of mining-induced ground fissures provided by the invention.

[0051] The above drawings include the following reference numerals:

[0052] 201, loose layer;

[0053] 302, bedrock layer;

[0054] 303, upper basic top;

[0055] 304, lower basic top;

[0056] 305. Direct top;

[0057] 306, coal seam;

[0058] 307, floor rock layer;

[0059] 401, ground fissure F1;

[0060] 402, ground fissure F2;

[0061] 403. Closure line of ground fissure;

[0062] 404, ground fissure F3;

[0063] 501. Monitoring point. DETAILED DESCRIPTION

[0064] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0065] like Figure 1As shown, an embodiment of the present invention provides a method for analyzing the formation and development of mining-induced ground fissures, comprising:

[0066] S10. Determine the basic information of the test sample of the coal mining face;

[0067] S20, processing basic information of model construction and constructing a numerical simulation model;

[0068] S30, simulating excavation of the model and preliminarily monitoring the locations of ground fissures caused by mining;

[0069] S40, re-excavating the initial model, arranging monitoring points around the locations where cracks are expected to be generated, and monitoring the stress and displacement before and after the formation of the mining-induced ground cracks;

[0070] S50. Continue excavation and monitor the development of ground fissures caused by mining and the stress and displacement during the repair process;

[0071] S60: Summarize and process the monitoring data.

[0072] The above method can accurately analyze and predict the deformation of the ground surface during coal mining, especially in the formation, development and self-repair mechanism of ground fissures, providing important data support for safe production and environmental protection of coal mines. The implementation of this method has significantly improved the safety and efficiency of coal mining. By predicting the formation and changes of ground fissures in advance, coal mines can take targeted preventive measures, such as changing the mining sequence and controlling the mining speed, to avoid irreversible damage to the surface environment. At the same time, it also ensures the safety of communities around coal mines and the stability of infrastructure.

[0073] like Figure 2 and Figure 3 As shown, S10 includes:

[0074] S11. Select a coal mining face as the research object, arrange multiple drilling holes within the face to obtain rock formation information and soil medium characteristics to determine the initial structure of the stratum;

[0075] S12. Conduct mechanical parameter tests on rock and soil samples to obtain the strength, density, water content, Young's modulus, and Poisson's ratio parameters of each rock and soil layer.

[0076] Through these detailed parameter tests, the mechanical response of the stratum during the mining process can be simulated more accurately, providing a more scientific basis for the prediction and control of ground fissures. It is suitable for coal mining areas with complex geological conditions that require refined management. Refined parameter testing and simulation improve the accuracy of prediction, enabling coal mines to more effectively control surface deformation during mining, reduce the formation of ground fissures, and reduce safety risks caused by geological problems in mining areas.

[0077] Specifically, S20 includes:

[0078] S21. Conduct preliminary modeling based on geological data and test data;

[0079] S22. Determine the stratigraphic division of the working face: divide the rock layers in the working face area from top to bottom into loose layer 201, bedrock layer 302, upper basic roof 303, lower basic roof 304, direct roof 305, coal seam 306, and floor rock layer 307.

[0080] This hierarchical modeling method can more carefully analyze the role and response of different rock layers in the mining process, which helps to formulate targeted mining strategies and surface protection measures. It is suitable for coal mining projects that require stratum stability analysis and surface deformation prediction. Through hierarchical modeling, coal mines can more accurately evaluate the response of different rock layers to mining activities, thereby optimizing mining plans, reducing surface deformation and the formation of ground fissures, and protecting the ecological environment and personnel safety around the mining area.

[0081] Among them, in S21, subdivision layers and multi-regional block construction are used for modeling. Through subdivision layers and multi-regional block construction, the mechanical behavior of the strata can be simulated more accurately, especially the complex mechanical response during the formation and development of ground fissures, providing a more accurate model basis for the prediction of surface deformation during coal mining. It is suitable for coal mining areas that require high-precision stratum simulation, such as mining areas with complex geological structures.

[0082] like Figure 3 As shown, S22 includes:

[0083] S221, simulate the excavation of the coal seam 306 of the built model, and as the working face advances, the roof rock layer collapses. At this time, the thickness of the collapsed rock layer H5 is recorded, and this part of the rock layer is divided into a group, namely, the direct roof 305;

[0084] S222. Continue simulating excavation. With the continuous collapse of the direct roof 305, a rock layer of a certain thickness on the direct roof 305 begins to break and collapse, and delamination cracks appear in the rock layer overlying the broken rock layer. At this time, the thickness H4 of the collapsed rock layer is recorded, and this part of the rock layer is divided into a group, namely, the lower basic roof 304; continue excavation, and the rock layer with cracks begins to break and collapse. The thickness H3 of this part of the rock layer is recorded, and this part of the rock layer is divided into a group, namely, the upper basic roof 303.

[0085] This staged simulated excavation and rock strata division can more clearly reveal the mechanical mechanisms of different stages of ground fissure formation, and provide more specific data guidance for the prediction and control of ground fissures during coal mining. It is suitable for coal mining areas where research and control of ground fissure formation mechanisms are required.

[0086] Furthermore, S22 also includes:

[0087] S223, dividing the rock layers between the loose layer 201 and the basic top into one group, namely, the bedrock layer 302, with a thickness of H2;

[0088] S224. The thicknesses of the loose layer 201, the coal seam 306 and the bottom rock layer 307 are represented by H1, H6 and H7 respectively.

[0089] Through this detailed division of rock layer thickness, the role of different rock layers in the formation and development of ground fissures can be evaluated more accurately, providing more precise data support for the analysis of stratum stability during coal mining, and is suitable for coal mining projects that require rock layer stability analysis and ground fissure prediction.

[0090] like Figure 4 As shown in the two figures (a) and (b) included in the figure, S30 includes:

[0091] S31, adjusting the grouped model to the unexcavated state of the coal seam 306, and simulating the excavation of the coal seam 306 again, and the excavation progress is consistent with the actual work construction progress according to the set time ratio;

[0092] S32. As the working face continues to advance to a certain distance, the bedrock layer 302 breaks and sinks, and mining-induced ground fissures are generated in the loose layer 201. The location coordinates, opening degree, size and spatial distribution characteristics of the mining-induced ground fissures are recorded, and the ground fissures are numbered and recorded.

[0093] The number record can be in the following form:

[0094]

[0095] This dynamic monitoring and recording method can track the changes in ground fissures in real time, providing real-time data support for surface deformation prediction and ground fissure control during coal mining, helping to adjust mining strategies in a timely manner and reduce the impact on the surface environment.

[0096] like Figure 5 As shown, S40 includes:

[0097] S411, vertical monitoring point arrangement: take the ground fissure occurrence point at the contact surface between the loose layer 201 and the bedrock layer 302 as the starting point of the ground fissure for monitoring point arrangement, and arrange the monitoring points equidistantly upward from the starting point in the vertical direction, and arrange the monitoring points on the blocks on both sides of the ground fissure;

[0098] S412. Horizontal monitoring point arrangement: Arrange at equal distances on the same horizontal line of vertical monitoring points;

[0099] S421, stress monitoring: obtaining stress data in the x-direction, y-direction, and z-direction of each monitoring point;

[0100] S422, displacement monitoring: displacement is calculated based on the coordinate change between two monitoring points originally at the same level. The formula is as follows:

[0101] D=|X i动 ′-X i定 ∣=√(x i动 ′-x i定 ) 2 +(y i动 ′-y i定 ) 2 +(z i动 ′-z i定 ) 2 ,

[0102] Where D is the distance that the rock mass moves after the ground fissure is generated, X i动 ′ is the coordinate of the moving side of the ground fissure after the ground fissure is generated, X i定 It is the side coordinate that has not moved after the ground fissure occurs.

[0103] The above-mentioned comprehensive stress and displacement monitoring improves the accuracy of ground fissure control, enabling coal mines to promptly detect precursors of surface deformation during mining, take measures to prevent further development of ground fissures, and ensure the safety of mining activities and the stability of the surface environment.

[0104] Specifically, Figure 4 As shown in the two figures (a) and (b) included in the figure, S50 includes:

[0105] As the working face continues to advance, the first complete mining ground fissure is formed. Two main fissures are defined according to the advancing direction, namely F1 and F2. When the working face continues to advance for a distance, the ground fissure F2 closes, recorded as F2′, and the third main ground fissure F3 is formed; among them,

[0106] The monitoring process of the ground fissure F3 is consistent with the operation of steps S30 and S40, and its stress and displacement are monitored;

[0107] The ground fissure F2′ is monitored by continuing to use the ground fissure F2 monitoring point arrangement in S40.

[0108] The above-mentioned continuous monitoring of the formation, closure and generation of new ground fissures can reveal the dynamic change law of ground fissures and provide more continuous data support for ground fissure control and surface deformation prediction during coal mining. Continuous monitoring of the dynamic changes of ground fissures enables coal mines to grasp the development trend of ground fissures in a timely manner, adjust mining strategies, effectively control the closure of ground fissures and the generation of new cracks, reduce the impact of mining activities on the surface environment, and improve the safety of coal mining.

[0109] Among them, S60 includes:

[0110] S61. List and analyze the data at the ground fissures F1 and F2 obtained when the ground fissures caused by mining are formed for the first time, and explore the mechanical mechanism of the formation of ground fissures caused by mining;

[0111] S62, comparative analysis and processing of the data at the ground fissures F2 and F2′ from the formation to the restoration, to explore the restoration mechanism of the ground fissures;

[0112] S63. Comprehensively analyze the data obtained from the ground fissure F3 and the data in S61 to explore the differences and connections between the development and formation mechanical mechanisms of ground fissures.

[0113] Through this comprehensive analysis, we can have a deeper understanding of the mechanical mechanism of the formation, development and repair process of ground fissures, and provide a more scientific theoretical basis for the prediction and control of ground fissures in the process of coal mining. It is suitable for coal mining areas where research on the formation mechanism and repair mechanism of ground fissures is needed, as well as projects that need to formulate scientific mining plans and environmental protection measures. By comprehensively analyzing the formation and repair mechanism of ground fissures, coal mines can have a deeper understanding of the inherent laws of ground fissure activities, formulate scientific mining plans and environmental protection measures, effectively prevent and control ground fissure disasters, improve the safety and efficiency of coal mining, and reduce damage to the surface environment.

[0114] The mining-induced ground fissure formation and development analysis method provided in this application can accurately capture the stress and displacement changes in the formation, development and repair process of ground fissures through refined stratigraphic division and dynamic monitoring, and provide a scientific basis for the prediction of surface deformation and control of ground fissures during coal mining. The application of this method not only helps to improve the safety and sustainability of coal mining and reduce the impact on the environment, but also provides a reference for other underground projects such as urban underground space development and tunnel excavation, helping to predict and control surface deformation caused by engineering activities. In the fields of geological disaster early warning and environmental protection, this method also plays an important role and can improve the safety and sustainability of engineering activities.

[0115] This method improves the safety and efficiency of coal mining. By accurately predicting and controlling ground fissures, it reduces the impact on the surrounding environment and improves the quality of life of people around the mining area. It also provides valuable reference experience for other underground projects. It is not only applicable to coal mining, but also widely used in underground engineering fields such as tunnel excavation and underground construction. It is of great value in predicting and controlling surface deformation caused by engineering activities. The application of this method can also play a role in geological disaster warning, urban planning, environmental protection and other aspects.

[0116] The above is only an optional embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may be modified and varied in various ways. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

[0117] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0118] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of this solution. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be considered as a part of the specification. In all examples shown and discussed here, any specific value should be interpreted as being only exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so that once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0119] In the description of this scheme, it needs to be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing this scheme and simplifying the description. Unless otherwise stated, these directional words do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation. Therefore, they cannot be understood as limiting the scope of protection of this scheme; the directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0120] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0121] In addition, it should be noted that the use of words such as "first" and "second" to limit components is only to facilitate the distinction between corresponding components. Unless otherwise stated, the above words have no special meaning and therefore cannot be understood as limiting the scope of protection of this scheme.

Claims

1. A method for analyzing the formation and development of mining-induced ground fissures, characterized in that: include: S10. Determine the basic information of the test sample of the coal mining face; S20, processing basic information of model construction and constructing a numerical simulation model; S30, simulating excavation of the model and preliminarily monitoring the locations of ground fissures caused by mining; S40, re-excavating the initial model, arranging monitoring points around the locations where cracks are expected to be generated, and monitoring the stress and displacement before and after the formation of the mining-induced ground cracks; S50. Continue excavation and monitor the development of ground fissures caused by mining and the stress and displacement during the repair process; S60: Summarize and process the monitoring data.

2. The method for analyzing the formation and development of mining-induced ground fissures according to claim 1, characterized in that: S10 includes: S11, select a coal mining face as the research object, arrange multiple drilling holes within the range of the face to obtain rock formation occurrence information and soil medium characteristics of the face to determine the initial structure of the stratum; S12. Conduct mechanical parameter tests on rock and soil samples to obtain the strength, density, water content, Young's modulus, and Poisson's ratio parameters of each rock and soil layer.

3. The method for analyzing the formation and development of mining-induced ground fissures according to claim 2, characterized in that: The S20 includes: S21. Conduct preliminary modeling based on geological data and test data; S22. Determine the stratigraphic division of the working face: divide the rock strata in the working face area into loose layer (201), bedrock layer (302), upper basic roof (303), lower basic roof (304), direct roof (305), coal seam (306), and floor rock layer (307) from top to bottom.

4. The method for analyzing the formation and development of mining-induced ground fissures according to claim 3, characterized in that: In S21, subdivision layers are used during modeling, and multiple regions are divided into blocks for construction.

5. The method for analyzing the formation and development of mining-induced ground fissures according to claim 3, characterized in that: S22 includes: S221, simulate excavation of the coal seam (306) of the built model, and as the working face advances, the roof rock layer collapses, and at this time, the thickness H5 of the collapsed rock layer is recorded, and this part of the rock layer is divided into a group, namely, the direct roof (305); S222, continue to simulate excavation, with the continuous collapse of the direct roof (305), a certain thickness of rock layer on the direct roof (305) begins to break and collapse, and delamination cracks appear in the rock layer overlying the broken rock layer. At this time, the thickness H4 of the collapsed rock layer is recorded, and this part of the rock layer is divided into a group, namely the lower basic roof (304); continue to excavate, the rock layer with cracks begins to break and collapse, and the thickness H3 of this part of the rock layer is recorded, and this part of the rock layer is divided into a group, namely the upper basic roof (303).

6. The method for analyzing the formation and development of mining-induced ground fissures according to claim 5, characterized in that: The S22 also includes: S223, dividing the rock layers between the loose layer (201) and the basic top into one group, namely the bedrock layer (302), with a thickness of H2; S224. The thicknesses of the loose layer (201), the coal seam (306), and the bottom rock layer (307) are represented by H1, H6, and H7, respectively.

7. The method for analyzing the formation and development of mining-induced ground fissures according to claim 3, characterized in that: S30 includes: S31, adjusting the grouped models to the un-excavated state of the coal seam (306), and simulating the excavation of the coal seam (306) again, wherein the excavation progress is consistent with the actual work construction progress according to the set time ratio; S32. As the working face continues to advance to a certain distance, the bedrock layer (302) fractures and sinks, and the loose layer (201) generates mining-induced ground fissures. The position coordinates, opening degree, size and spatial distribution characteristics of the mining-induced ground fissures are recorded, and the ground fissures are numbered and recorded.

8. The method for analyzing the formation and development of mining-induced ground fissures according to claim 3, characterized in that: S40 includes: S411, vertical monitoring point arrangement: taking the ground fissure occurrence point on the contact surface between the loose layer (201) and the bedrock layer (302) as the starting point of the ground fissure for monitoring point arrangement, arranging the monitoring points equidistantly upward from the starting point in the vertical direction, and arranging the monitoring points on the blocks on both sides of the ground fissure; S412. Horizontal monitoring point arrangement: Arrange at equal distances on the same horizontal line of vertical monitoring points; S421, stress monitoring: obtaining stress data in the x-direction, y-direction, and z-direction of each monitoring point; S422, displacement monitoring: displacement is calculated based on the coordinate change between two monitoring points originally at the same level. The formula is as follows: D=∣X i动 ′-X i定 ∣=√(x i动 ′-x i定 ) 2 +(y i动 ′-y i定 ) 2 +(z i动 ′-z i定 ) 2 , Where D is the distance that the rock mass moves after the ground fissure is generated, X i动 ′ is the coordinate of the moving side of the ground fissure after the ground fissure is generated, X i定 It is the side coordinate that has not moved after the ground fissure occurs.

9. The method for analyzing the formation and development of mining-induced ground fissures according to claim 7, characterized in that: S50 includes: As the working face continues to advance, the first complete mining ground fissure is formed. Two main fissures are defined according to the advancing direction, namely F1 and F2. When the working face continues to advance for a distance, the ground fissure F2 closes, which is recorded as F2′, and the third main ground fissure F3 is formed; among them, The monitoring process of the ground fissure F3 is consistent with the operation of steps S30 and S40, and its stress and displacement are monitored; The ground fissure F2′ is monitored by continuing to use the ground fissure F2 monitoring point arrangement in S40.

10. The method for analyzing the formation and development of mining-induced ground fissures according to claim 9, characterized in that: S60 includes: S61. List and analyze the data at the ground fissures F1 and F2 obtained when the ground fissures caused by mining are formed for the first time, and explore the mechanical mechanism of the formation of ground fissures caused by mining; S62, comparative analysis and processing of the data at the ground fissures F2 and F2′ from the formation to the restoration, to explore the restoration mechanism of the ground fissures; S63. Comprehensively analyze the data obtained from the ground fissure F3 and the data in S61 to explore the differences and connections between the development and formation mechanical mechanisms of ground fissures.

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