Well-ground combined exploration and treatment integrated method for deep collapse column

Abstract

The invention discloses a well-ground combined exploration and treatment integrated method for a deep collapse column, and belongs to the technical field of exploration and treatment of coal mining collapse columns, and the method comprises the following steps: carrying out geophysical exploration and high-density geophysical exploration inversion, and preliminarily determining the position, development range and the like of a suspected collapse column; performing ground or underground drilling at the position of the suspected collapse column in combination with the current mining situation and planning of the mine, and further determining whether the collapse column develops or not; after existence of the collapse column is confirmed, underground geophysical prospecting and underground drilling are carried out, and the development range, the water yield property and the water conductivity of the collapse column are determined; and a collapse column ground or underground grouting treatment scheme is formulated, and the treatment effect is ensured. The advanced exploration treatment method for the collapse column is constructed by comprehensively considering the geological conditions, the hydrogeological conditions and the mining plan of a mining area, the development position and range of the collapse column are accurately and flexibly found out, the water yield property and the water conductivity of the collapse column are comprehensively evaluated, the exploration accuracy of the collapse column is improved, and collapse column treatment and mine safety production are guided.

Description

Technical Field

[0001] The present invention relates to the technical field of coal mining subsidence column exploration and treatment, and in particular to an integrated method for well-ground combined exploration and treatment of deep subsidence columns. Background Art

[0002] The collapse column is a common geological structure in the eastern coal mining area. Its development height and area are different, the plane shape is different, and the central axis of the column is complex and changeable, and extremely irregular. The roots of the collapse column are generally located in the thick limestone of the Cambrian or Ordovician. In the process of coal mining, the accidental exposure of the collapse column during the mining of the tunnel and working face may cause water inrush accidents, causing huge losses to production. The existing collapse column exploration and control technologies mainly include geological prediction, water quality warning, geophysical positioning, drilling control and directional plugging. The accuracy of such methods is often affected by multiple factors such as the complex underground tunnel system, and the economic cost is relatively high. Therefore, it is of great significance to accurately identify the development location, range, water richness, water conductivity, etc. of the collapse column and treat it, while reducing the economic cost, for the prevention and control of water hazards in coal mines. Summary of the invention

[0003] Technical problem to be solved: In view of the technical problem that the accuracy of collapse column detection in the prior art coal mining process is often affected by multiple factors such as the complex underground tunnel system, and the economic cost is relatively high, the present invention provides an integrated method for the joint exploration and treatment of deep collapse columns between the mine and the ground, which comprehensively considers the geological conditions, hydrogeological conditions and mining plan of the mining area, constructs an advanced exploration and treatment method for collapse columns, accurately and flexibly identifies the development location and range of collapse columns, comprehensively evaluates their water richness and water conductivity, improves the accuracy of collapse column detection and reduces economic costs, and guides collapse column treatment and mine safety production.

[0004] Technical solution: The invention discloses a method for integrated exploration and treatment of deep subsidence columns, the method comprising the following steps: Step 1: Carry out ground geophysical survey and verification work in the entire study area, and adopt a combination of ground high-precision three-dimensional seismic exploration and ground high-precision three-dimensional transient electromagnetic geophysical exploration to identify the development morphology, boundaries and water-rich abnormal areas of the collapse column within the mining area, and further screen, interpret and verify the original exploration results; Step 2: Combined with the further screening results of high-precision geophysical exploration on the ground, after the abnormal area is determined, combined with the underground construction conditions, an exploration verification borehole is constructed on the ground or underground in advance at the center of the collapse column plane to verify the geophysical exploration results and clarify whether the collapse column exists; Step 3: According to the results of ground or underground geophysical exploration and drilling, if the development of subsidence columns is not found, 1 to 2 verification holes crossing the subsidence columns can be appropriately constructed according to the underground tunnel excavation to the nearby location for further verification; if the development of subsidence columns is found, 3 to 4 exploration holes of the development range of subsidence columns can be constructed at appropriate locations according to the progress of underground tunnel excavation, and at least 3 holes can be drilled in the direction of the bottom plate at appropriate locations to comprehensively judge the water richness and water conductivity of the subsidence columns; Step 4: In combination with the mine excavation planning and design and the comprehensive exploration results of collapse columns, comprehensive consideration is given to multiple factors including underground construction conditions, feasibility of grouting construction, and economic costs to select appropriate coal pillar retention or grouting control plans; when the subsequent shaft and tunnel engineering meets the conditions for collapse column grouting construction, carry out targeted control projects for collapse columns and ensure the control effect.

[0005] Preferably, the specific steps of high-precision three-dimensional seismic exploration of the ground and high-precision three-dimensional transient electromagnetic exploration of the ground collapse column in step 1 are: Step S1: Collect geological, hydrogeological and existing exploration data of the study area, conduct comprehensive analysis, and clarify the research objectives and key exploration areas; prepare seismographs, geophones, transmitters, receivers, and data processing software tools according to exploration needs to ensure that the equipment and tools have good performance and meet the exploration accuracy requirements; Step S2: high-precision three-dimensional ground seismic exploration: design a reasonable survey network density and survey line layout according to the area of ​​the study area, the complexity of the geological structure and the exploration target to ensure coverage of the entire study area; utilize the difference in the propagation speed of seismic waves in different media, artificially stimulate seismic waves and record the signals reflected underground to collect seismic wave data; filter, denoise, stack, and offset the collected seismic data to extract underground structure information and identify the development morphology and boundaries of collapse columns and fault geological structures; Step S3: high-precision three-dimensional transient electromagnetic exploration on the ground: coordinate with the seismic exploration network to set up transient electromagnetic measurement points and lines to ensure coverage of key areas; use the principle of electromagnetic induction to emit pulse current underground, observe the response of the secondary field generated thereby over time, and collect electromagnetic data; invert the transient electromagnetic data, analyze the underground electrical distribution characteristics, identify water-rich abnormal areas, and assist in judging the water content in the collapse column; Step S4: Fuse the results of seismic exploration and transient electromagnetic geophysical exploration, and carefully screen and interpret the fused data to further clarify the spatial morphology, boundaries and specific locations of water-rich anomaly areas of the collapse column.

[0006] Preferably, the specific construction steps of the ground or underground exploration verification drilling in step 2 are: Step L1: Organize professionals to conduct on-site surveys of the ground and underground construction areas to understand the ground structures, underground tunnel layout, ventilation conditions, and safety facilities, and give priority to underground construction to reduce economic costs; Step L2: If there are no drilling conditions underground, based on the detection results of step 1, determine the plane center position of the ground exploration borehole, and design the depth and aperture parameters of the borehole; if the initial detection shows that the suspected collapse column has exposed the main mining coal seam, the final position of the ground drilling hole can be located in the thin layer of Taiyuan limestone below the thickness of the safety waterproof layer of the bottom plate of the main mining coal seam, and coring is carried out throughout the hole, and rock and mineral identification, permeability and porosity tests are carried out on the core of the collapse column section to provide support for subsequent collapse column management, and It can verify whether the suspected collapse column has developed, and preliminarily explore the water-richness and water conductivity of the collapse column; if the initial detection of the suspected collapse column development does not reveal that the main mining coal seam is a hidden collapse column, the final hole position of the ground drilling must be located in the Cambrian or Ordovician thick limestone, and the whole hole must be cored. The core of the collapse column section can be used for rock and mineral identification, permeability, and porosity testing to provide support for subsequent collapse column management, and it can verify whether the suspected collapse column has developed, and preliminarily explore the water-richness and water conductivity of the collapse column; Step L3: If the conditions for drilling construction are available underground, determine the optimal drilling position, drilling inclination, and drilling depth parameters in combination with the construction requirements of exploratory drilling; the drilling position must be outside the suspected subsidence column's waterproof coal / rock pillar, the drilling inclination must be close to the coal seam inclination, and the drilling depth must be at the center of the suspected subsidence column.

[0007] Preferably, the specific construction steps of the verification hole of the suspected collapse column and the collapse column exploration hole in step 3 are: Step M1: According to the exploration and verification results of step 2, if the development of the subsidence column is not confirmed, the verification hole parameters of the suspected subsidence column in the well are as follows: the verification hole inclination is nearly horizontal, the inclination is measured every 10m during the drilling construction, the whole hole is cored and the suspected subsidence column is exposed before the hole is terminated to further ensure that the suspected subsidence column is not developed; Step M2: According to the exploration and verification results of step 2, if the development of the subsidence column has been verified, no less than 3 exploration holes with the development range shall be constructed in the underground tunnel along the direction of the coal seam. The drilling position shall be located outside the anti-waterproof coal / rock pillar of the subsidence column, the drilling angle shall be similar to the coal seam inclination, the drilling depth shall be 10m after the subsidence column is exposed, and the whole hole shall be cored. The core of the subsidence column section can be used for rock and mineral identification, permeability and porosity testing to provide support for the subsequent subsidence column management; Step M3: According to the exploration and verification results of step 2, if the development of collapse columns has been verified, no less than 3 water-rich and water-conducting exploration holes shall be constructed in the direction of the bottom plate of the underground tunnel; the water pressure of the Cambrian or Ordovician limestone aquifer is inferred based on the collapse column area, and water-stop casings shall be placed in the bottom plate holes. During the drilling construction, the inclination shall be measured every no more than 10m; one of the holes shall be terminated at the center of the collapse column and vertically to the thin layer of Taiyuan limestone below the thickness of the safety waterproof layer of the bottom plate of the main mining coal seam; and no less than 2 other holes shall be terminated at the edge of the collapse column and vertically to the thin layer of Taiyuan limestone below the thickness of the safety waterproof layer of the bottom plate of the main mining coal seam. After the holes are drilled, water pressure tests shall be carried out respectively.

[0008] Preferably, the specific steps of coal pillar retention or grouting treatment in step 4 are: Step N1: Determine the scope of the coal pillar of the subsidence column according to the accurate exploration results of the development scope, water richness and water conductivity of the subsidence column in step 3; Step N2: Based on the precise exploration results of the development range, water-richness and water conductivity of the collapse column in step 3, determine the technical solution for grouting treatment of the collapse column; from a safety perspective, for the bottom plate grouting reinforcement project of the collapse column, focus on grouting to form a "water stop" with a thickness exceeding the thickness of the safe waterproof layer for mining at the working face in the thin layer of Taiyuan Formation limestone at the bottom of the main mining coal seam and its top plate outside the bottom plate damage zone of the working face, and at the same time consider the depth of the bottom plate damage zone of the working face to completely eliminate hidden dangers and ensure safe mining of the working face.

[0009] Preferably, the empirical formula for calculating the water-proof coal / rock pillar of the collapse column in step L3 / step M2 / step N1 is: ; In the above formula, L is the width of the anti-waterproof coal / rock pillar of the collapse column / m; K is the safety factor, which is 2~5; M is the thickness of the coal seam or the mining height / m; p is the actual head value of the Cambrian or Ordovician limestone aquifer / MPa; Kp is the tensile strength of coal / rock / MPa; Preferably, the thickness of the safety waterproof layer in step N2 is calculated using an empirical formula: ; In the above formula, t is the thickness of the safety waterproof layer / m; P is the actual water head value of the bottom waterproof layer / MPa; L is the width of the tunnel bottom plate, the working face opening cycle pressure step / m; γ is the average weight of the bottom waterproof layer / MN / m³; K p It is the tensile strength of the bottom plate waterproof layer / MPa.

[0010] Preferably, in step N2, the bottom plate damage zone is calculated using an empirical formula: h = 0.7007 + 0.1079L; or h=0.303L 0.8 ;or h=0.0085H+0.1665α+0.1079L-4.3579; In the above formula, h is the depth of the damaged zone of the working face mining floor / m; L is the inclined length of the working face / m; H is the mining depth / m; α is the inclination angle of the coal seam / °.

[0011] Compared with the prior art, the present invention has at least the following beneficial effects: 1. The present invention uses a combination of high-precision three-dimensional ground seismic exploration and high-precision three-dimensional transient electromagnetic geophysical exploration methods to accurately identify the development morphology, boundaries and water-rich abnormal areas of collapse columns within the entire study area; this method not only greatly improves the accuracy and efficiency of geological exploration, but also reduces the mining risks caused by unknown geological structures.

[0012] 2. Targeted ground or underground exploration and verification of drilling construction not only verifies the accuracy of ground geophysical exploration results, but also allows intuitive exploration of the development profile of subsidence columns, timely discovery and resolution of possible errors or omissions in geological exploration, and improves the reliability and accuracy of the entire exploration process. This flexible and comprehensive exploration strategy not only effectively avoids safety hazards such as water inrush and gas outbursts caused by subsidence columns, but also provides detailed data support for subsequent governance work.

[0013] 3. On the basis of fully considering factors such as mine excavation planning and design, underground construction conditions, feasibility of grouting construction and economic cost, choose appropriate coal pillar retention or grouting control plan, which not only ensures the scientificity and economy of the collapse column control plan, but also fully considers the actual needs and long-term benefits of mine production; through targeted control projects, such as grouting reinforcement, coal pillar retention, etc., the impact of collapse columns on mine production can be effectively reduced, and the safety and stability of mines can be improved.

[0014] 4. The present invention can accurately identify the development location, scope, water richness, water conductivity, etc. of the collapse column and treat it, which not only improves the effectiveness, pertinence and efficiency of the treatment work, but also greatly reduces the economic cost of collapse column exploration and provides safety guarantee for subsequent mining of the mine. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a flow chart of the integrated method for joint exploration and treatment of a collapsed column in the well and on the ground according to the present invention; Figure 2 It is a schematic plan view of the advance exploration of the development range, water richness and water conductivity of the collapse column of the present invention; Figure 3 It is a cross-sectional schematic diagram of the arrangement of drilling holes for grouting treatment of collapsed columns according to the present invention; Figure 4 The present invention is a schematic plan view of the arrangement of drilling holes for grouting treatment of collapsed columns. DETAILED DESCRIPTION

[0016] To make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the following will be combined with the attached Figures 1 to 4 The technical solutions of the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the described embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

[0017] The following is an example of a coal mine in Jiangsu: Figures 1 to 4 As shown, the present invention discloses an integrated method for well-ground joint exploration and treatment of deep subsidence columns, and the method comprises the following steps.

[0018] 1. Carry out ground geophysical survey and verification work in the entire study area, and adopt a combination of ground high-precision 3D seismic exploration and ground high-precision 3D transient electromagnetic geophysical exploration to identify the development morphology, boundaries and water-rich abnormal areas of the subsidence column within the mining area, and further screen, interpret and verify the original exploration results. Specific steps of ground high-precision 3D seismic exploration and ground high-precision 3D transient electromagnetic exploration of subsidence columns: (1) A coal mine exploration survey in Jiangsu Province found a suspected collapse column 2. The geological, hydrogeological and existing exploration data of the area were collected and analyzed comprehensively, and the west wing mining area, which was about to be mined, was identified as the research target and key exploration area. According to the exploration needs, tools such as seismographs, geophones, transmitters, receivers, and data processing software were prepared to ensure that the equipment and tools performed well and met the exploration accuracy requirements.

[0019] (2) High-precision 3D ground seismic exploration: Based on the area of ​​the west wing mining area, the complexity of the geological structure and the exploration objectives, a reasonable survey network density and survey line layout are designed to ensure coverage of the entire study area; the difference in the propagation speed of seismic waves in different media is used to artificially stimulate seismic waves and record the signals reflected underground to collect seismic wave data. The collected seismic data is filtered, denoised, superimposed, and offset and returned to the original position to extract underground structure information and identify the development morphology and boundaries of collapse columns and fault geological structures.

[0020] (3) High-precision three-dimensional transient electromagnetic exploration on the ground: coordinate with the seismic exploration network to set up transient electromagnetic measurement points and lines to ensure coverage of key areas. Using the principle of electromagnetic induction, pulse current is emitted into the ground, and the response of the secondary field generated by it is observed over time to collect electromagnetic data. Invert the transient electromagnetic data, analyze the underground electrical distribution characteristics, identify water-rich abnormal areas, and assist in determining the water content in the collapse column.

[0021] (4) Figure 2As shown, the results of seismic exploration and transient electromagnetic geophysical exploration are fused, and the fused data are carefully screened and interpreted to further clarify the spatial morphology, boundaries of the collapse column and the specific location of the water-rich anomaly area.

[0022] 2. Combined with the further screening results of high-precision geophysical exploration on the ground, after the abnormal area is determined, combined with the underground construction conditions, a ground or underground exploration verification borehole is constructed in advance at the center of the collapse column plane to verify the geophysical exploration results and clarify whether the collapse column exists. Specific construction steps for ground or underground exploration verification drilling: (1) Organize professional personnel to conduct on-site surveys of the ground and underground construction areas to understand the ground structures, underground tunnel layout, ventilation conditions, and safety facilities, and give priority to underground construction to reduce economic costs.

[0023] (2) During advance exploration and verification of the collapse column, if there are no conditions for drilling construction underground, based on the existing detection results, preliminary detection is carried out to reveal the suspected collapse column development through the main mining coal seam, determine the plane center position of the ground exploration borehole, and design the depth and aperture parameters of the borehole. If the initial detection shows that the suspected collapse column has been developed and exposed the main mining coal seam, the final hole of the ground drilling shall be located in the thin layer of Taiyuan Formation limestone below the thickness of the safety water-proof layer of the bottom plate of the main mining coal seam, and the whole hole shall be cored, and rock and mineral identification, permeability and porosity tests shall be carried out on the core of the collapse column section to provide support for the subsequent collapse column management, and it can be verified whether the suspected collapse column has been developed, and the water-richness and water conductivity of the collapse column can be preliminarily explored; if the initial detection shows that the suspected collapse column has not been developed and exposed the main mining coal seam as a concealed collapse column, the final hole of the ground drilling shall be located in the Cambrian or Ordovician thick limestone, and the whole hole shall be cored, and rock and mineral identification, permeability and porosity tests can be carried out on the core of the collapse column section to provide support for the subsequent collapse column management, and it can be verified whether the suspected collapse column has been developed, and the water-richness and water conductivity of the collapse column can be preliminarily explored; (3) If the conditions for drilling construction are available underground, the optimal drilling position, drilling inclination, and drilling depth parameters shall be determined in combination with the construction requirements of exploratory drilling. The drilling position shall be located outside the suspected subsidence column's waterproof coal / rock pillar, the drilling inclination shall be close to the coal seam inclination, and the drilling depth shall be located at the center of the suspected subsidence column.

[0024] In a specific embodiment, if Figure 2 As shown, the plane center position of the ground exploration borehole Q1 was determined. The final hole position of the ground borehole was located in the thin layer of Taiyuan limestone below the thickness of the main mining floor safety impermeable layer, and the whole hole was cored. The depth of Q1 borehole was 776.3m. According to the stratum exposed by the Q1 hole on the ground, the stratigraphic sequence of the Q1 hole at depths of 0-700m and 740-776.3m was normal, and the stratigraphic sequence of the hole depth of 626-740m was abnormal, indicating that the collapse column developed in this area; there was no water in the borehole, which preliminarily showed that the collapse column was water-rich and had poor water conductivity.

[0025] 3. According to the results of ground or underground geophysical exploration and drilling, if the development of the collapse column is not confirmed, 1~2 verification holes that cross the collapse column can be constructed appropriately according to the underground tunnel excavation to the nearby location for further verification; if the collapse column is confirmed, 3~4 exploration holes in the development range of the collapse column can be constructed at appropriate locations according to the progress of underground tunnel excavation, and at least 3 holes can be drilled in the direction of the bottom plate at appropriate locations to comprehensively judge the water-richness and water conductivity of the collapse column. Specific construction steps for verification holes of suspected collapse columns and exploration holes of collapse columns: (1) According to the exploration and verification results, if no collapse column is found, the verification hole parameters of suspected collapse column in the well are as follows: the inclination of the verification hole is near horizontal, the inclination is measured every 10m during the drilling construction, the whole hole is cored and the suspected collapse column is exposed before the hole is terminated to further ensure that the suspected collapse column is not developed; (2) According to the exploration and verification results, if the development of the subsidence column has been confirmed, no less than three exploration holes with the development range shall be constructed in the underground tunnel along the direction of the coal seam. The drilling position shall be located outside the anti-waterproof coal / rock pillar of the subsidence column, the drilling angle shall be similar to the coal seam inclination, and the drilling depth shall be 10m after the subsidence column is exposed. The whole hole shall be cored. The core of the subsidence column section can be used for rock and mineral identification, permeability and porosity testing to provide support for the subsequent subsidence column management; (3) Based on the exploration and verification results, if the development of collapse columns has been confirmed, no less than three water-rich and water-conductive exploration holes shall be constructed in the direction of the floor of the underground tunnel; based on the estimated water pressure of the Cambrian or Ordovician limestone aquifer in the collapse column area, water-stop casings shall be placed in the floor holes, and inclination measurements shall be made every 10 m during drilling construction; one of the holes shall be drilled to the center of the collapse column and vertically to the thin layer of Taiyuan limestone below the thickness of the safety impermeable layer of the floor of the main mining coal seam; and no less than two other holes shall be drilled to the edge of the collapse column and vertically to the thin layer of Taiyuan limestone below the thickness of the safety impermeable layer of the floor of the main mining coal seam. After drilling, water pressure tests shall be carried out on each of the holes.

[0026] In a specific embodiment, according to the exploration and verification results, it has been found that the collapse column is developed, and three exploration holes with development range are constructed in the underground tunnel along the coal seam direction, such as Figures 2~4 As shown in the figure, the drilling position is outside the anti-waterproof coal / rock pillar of the collapse column, the drilling inclination is close to the coal seam inclination of 22°, the drilling depth is 10m after the collapse column is exposed, and the whole hole is cored. The core of the collapse column section can be used for rock and mineral identification, permeability, porosity and other tests to provide support for the subsequent collapse column management. Among them, the empirical formula for calculating the anti-waterproof coal / rock pillar of the collapse column is: ; In the above formula, L is the width of the anti-waterproof coal / rock pillar of the collapse column / m; K is the safety factor, which is 5; M is the thickness of the coal seam or the mining height / m, which is 4m; p is the actual head value of the Cambrian or Ordovician limestone aquifer / MPa, which is 6.0MPa; Kp is the tensile strength of coal / rock / MPa, and the value is 0.64MPa. After calculation, it is found that the width of the anti-waterproof coal / rock pillar of the collapse column is 53.03m.

[0027] According to the exploration and verification results, it has been found that the collapse column has developed. Figures 2~4 As shown, three water-rich and water-conducting exploration holes were constructed in the direction of the floor of the underground tunnel. The water pressure of the Ordovician limestone aquifer was inferred according to the collapse column area, and a 30m water-stop casing was placed under the floor hole. During the drilling construction, the inclination was measured every no more than 10m; one of the holes ended at the center of the collapse column and vertically reached the thin layer of limestone of the Taiyuan Formation below the thickness of the safety water-blocking layer of the floor of the main mining coal seam, and no less than two other holes ended at the edge of the collapse column and vertically reached the thin layer of limestone of the Taiyuan Formation below the thickness of the safety water-blocking layer of the floor of the main mining coal seam. After the holes were drilled, water pressure tests were carried out respectively. The results of the water pressure tests showed that the water conductivity of the collapse column was poor.

[0028] 4. Combined with the mining planning and design and the comprehensive exploration results of the subsidence column, comprehensively consider the underground construction conditions, the feasibility of grouting construction, and the economic cost, and select the appropriate coal pillar retention or grouting treatment plan; when the subsequent shaft and tunnel engineering has the conditions for the subsidence column grouting construction, carry out the targeted treatment project of the subsidence column and ensure the treatment effect. Specific steps for coal pillar retention or grouting treatment: (1) Determine the scope of the coal pillar to be retained based on the precise exploration results of the development range, water richness and water conductivity of the subsidence column.

[0029] (2) Based on the precise exploration results of the development range, water richness and water conductivity of the collapse column, the technical scheme for the grouting treatment of the collapse column is determined; from a safety perspective, for the bottom plate grouting reinforcement project of the collapse column, the focus is on grouting to form a "water stop" with a thickness exceeding the thickness of the safe waterproof layer for mining at the working face, outside the bottom plate damage zone of the working face, in the thin layer of Taiyuan Formation limestone at the bottom of the main mining coal seam and its top plate. At the same time, the depth of the bottom plate damage zone of the working face should be considered to completely eliminate hidden dangers and ensure safe mining at the working face.

[0030] In a specific embodiment, the thickness of the safety waterproof layer is calculated using the empirical formula: ; In the above formula, t is the thickness of the safety waterproof layer / m; P is the actual water head value of the bottom waterproof layer / MPa, which is 6.0MPa; L is the width of the tunnel bottom plate, the periodic pressure step distance of the working face opening / m, which is 20m; γ is the average weight of the bottom waterproof layer / MN / m³, which is 0.02548MN / m³; K p is the tensile strength of the bottom plate waterproof layer / MPa, the value is 3.65MPa. After calculation, the thickness of the safe waterproof layer is 17.4m.

[0031] Empirical formula for calculating the bottom plate damage zone: h = 0.7007 + 0.1079L; or h=0.303L 0.8 ;or h=0.0085H+0.1665α+0.1079L-4.3579; In the above formula, h is the depth of the damaged zone of the working face mining floor / m; L is the inclined length of the working face / m, which is 238m; H is the mining depth / m, which is 700m; α is the inclination angle of the coal seam / °, which is 30°. It is calculated that the maximum depth of the damaged zone of the working face mining floor is 33.3m.

[0032] The total thickness of the coal floor aquifer and the floor Taihui aquifer is about 58m, which is greater than the sum of the depth of the working face mining floor damage zone and the thickness of the safety aquifer. In theory, it is possible to achieve safe mining under pressure. However, considering the huge risk of the development of collapse columns, especially to prevent the subsequent disturbance of the working face mining from activating collapse columns and causing water inrush, it is necessary to take corresponding floor grouting reinforcement measures in advance before the working face is mined to the influence range of the collapse column. Therefore, from a safety perspective, the floor grouting reinforcement project for the collapse column focuses on the formation of a "water stopper" (not less than 17.4m, with a value of 20m) with a thickness exceeding the thickness of the working face mining safety aquifer in the four-ash area of ​​the floor and its roof through grouting, so as to completely eliminate hidden dangers and ensure safe mining of the working face.

[0033] At the same time, combined with the on-site engineering experience, the main technical points of grouting treatment of collapsed columns are proposed as follows: (1) Grouting reinforcement and filling are carried out on the collapse column crushing zone located in the fourth ash layer of the bottom plate below the coal bottom plate damage zone, so that the grouting reinforcement section can form a "water stopper" with a safety waterproof layer thickness greater than 17.4m (the value is 20m), blocking the hydraulic connection between the coal seam mining influence range and the upper and lower aquifers.

[0034] (2) Drilling and grouting are used to reinforce the fracture zone around the collapse column so that the "water stop plug" can be consolidated in the normal rock mass around the collapse column.

[0035] (3) Use the grouting holes as inspection holes to test the grouting effect and conduct a safety evaluation of the grouting effect to ensure that the working face can be safely pushed through the collapse column area.

[0036] The method of the present invention realizes the accurate identification of the development morphology, boundaries and water-rich abnormal areas of sinkholes within the overall scope of the study area by comprehensively and flexibly using ground high-precision three-dimensional geophysical exploration and downhole drilling technology. It not only improves the effectiveness, pertinence and efficiency of the management work, but also greatly reduces the economic cost of sinkhole exploration and management, providing safety guarantee for the subsequent mining of the mine.

[0037] The above are preferred embodiments of the present invention. It should be pointed out that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for integrated exploration and treatment of deep subsidence columns by combining well and ground exploration, characterized in that: The method comprises the following steps: Step 1: Carry out ground geophysical survey and verification work in the entire study area, and adopt a combination of ground high-precision three-dimensional seismic exploration and ground high-precision three-dimensional transient electromagnetic geophysical exploration to identify the development morphology, boundaries and water-rich abnormal areas of the collapse column within the mining area, and further screen, interpret and verify the original exploration results; Step 2: Combined with the further screening results of high-precision geophysical exploration on the ground, after the abnormal area is determined, combined with the underground construction conditions, an exploration verification borehole is constructed on the ground or underground in advance at the center of the collapse column plane to verify the geophysical exploration results and clarify whether the collapse column exists; Step 3: According to the results of ground or underground geophysical exploration and drilling, if the development of subsidence columns is not found, 1 to 2 verification holes crossing the subsidence columns can be appropriately constructed according to the underground tunnel excavation to the nearby location for further verification; if the development of subsidence columns is found, 3 to 4 exploration holes of the development range of subsidence columns can be constructed at appropriate locations according to the progress of underground tunnel excavation, and at least 3 holes can be drilled in the direction of the bottom plate at appropriate locations to comprehensively judge the water richness and water conductivity of the subsidence columns; Step 4: In combination with the mine excavation planning and design and the comprehensive exploration results of collapse columns, comprehensive consideration is given to multiple factors including underground construction conditions, feasibility of grouting construction, and economic costs to select appropriate coal pillar retention or grouting control plans; when the subsequent shaft and tunnel engineering meets the conditions for collapse column grouting construction, carry out targeted control projects for collapse columns and ensure the control effect.

2. The integrated well-ground exploration and treatment method for deep subsidence columns according to claim 1 is characterized in that: The specific steps of high-precision 3D seismic exploration and high-precision 3D transient electromagnetic exploration of the subsidence column in step 1 are as follows: Step S1: Collect geological, hydrogeological and existing exploration data of the study area, conduct comprehensive analysis, and clarify the research objectives and key exploration areas; prepare seismographs, geophones, transmitters, receivers, and data processing software tools according to exploration needs to ensure that the equipment and tools have good performance and meet the exploration accuracy requirements; Step S2: high-precision three-dimensional ground seismic exploration: design a reasonable survey network density and survey line layout according to the area of ​​the study area, the complexity of the geological structure and the exploration target to ensure coverage of the entire study area; utilize the difference in the propagation speed of seismic waves in different media, artificially stimulate seismic waves and record the signals reflected underground to collect seismic wave data; filter, denoise, stack, and offset the collected seismic data to extract underground structure information and identify the development morphology and boundaries of collapse columns and fault geological structures; Step S3: Ground high-precision three-dimensional transient electromagnetic survey: coordinate with the seismic survey network to set up transient electromagnetic survey points and survey lines to ensure coverage of key areas; Using the principle of electromagnetic induction, pulse current is emitted underground, the response of the secondary field generated thereby is observed over time, and electromagnetic data is collected; transient electromagnetic data is inverted, the underground electrical distribution characteristics are analyzed, water-rich abnormal areas are identified, and the water content in the collapse column is assisted in judging; Step S4: Fuse the results of seismic exploration and transient electromagnetic geophysical exploration, and carefully screen and interpret the fused data to further clarify the spatial morphology, boundaries and specific locations of water-rich anomaly areas of the collapse column.

3. The integrated well-ground exploration and treatment method for deep subsidence columns according to claim 2 is characterized in that: Specific construction steps for ground or underground exploration and verification of drilling in step 2: Step L1: Organize professionals to conduct on-site surveys of the ground and underground construction areas to understand the ground structures, underground tunnel layout, ventilation conditions, and safety facilities, and give priority to underground construction to reduce economic costs; Step L2: If there are no drilling conditions underground, based on the detection results of step 1, determine the plane center position of the ground exploration borehole, and design the depth and aperture parameters of the borehole; if the initial detection shows that the suspected collapse column has exposed the main mining coal seam, the final position of the ground drilling hole can be located in the thin layer of Taiyuan limestone below the thickness of the safety waterproof layer of the bottom plate of the main mining coal seam, and coring is carried out throughout the hole, and rock and mineral identification, permeability and porosity tests are carried out on the core of the collapse column section to provide support for subsequent collapse column management, and It can verify whether the suspected collapse column has developed, and preliminarily explore the water-richness and water conductivity of the collapse column; if the initial detection of the suspected collapse column development does not reveal that the main mining coal seam is a hidden collapse column, the final hole position of the ground drilling must be located in the Cambrian or Ordovician thick limestone, and the whole hole must be cored. The core of the collapse column section can be used for rock and mineral identification, permeability, and porosity testing to provide support for subsequent collapse column management, and it can verify whether the suspected collapse column has developed, and preliminarily explore the water-richness and water conductivity of the collapse column; Step L3: If the conditions for drilling construction are available underground, determine the optimal drilling position, drilling inclination, and drilling depth parameters in combination with the construction requirements of exploratory drilling; the drilling position must be outside the suspected subsidence column's waterproof coal / rock pillar, the drilling inclination must be close to the coal seam inclination, and the drilling depth must be at the center of the suspected subsidence column.

4. The integrated well-ground exploration and treatment method for deep subsidence columns according to claim 3 is characterized in that: Specific construction steps for the verification hole of the suspected collapse column and the collapse column exploration hole in step 3: Step M1: According to the exploration and verification results of step 2, if the development of the subsidence column is not confirmed, the verification hole parameters of the suspected subsidence column in the well are as follows: the verification hole inclination is nearly horizontal, the inclination is measured every 10m during the drilling construction, the whole hole is cored and the suspected subsidence column is exposed before the hole is terminated to further ensure that the suspected subsidence column is not developed; Step M2: According to the exploration and verification results of step 2, if the development of the subsidence column has been verified, no less than 3 exploration holes with the development range shall be constructed in the underground tunnel along the direction of the coal seam. The drilling position shall be located outside the anti-waterproof coal / rock pillar of the subsidence column, the drilling angle shall be similar to the coal seam inclination, the drilling depth shall be 10m after the subsidence column is exposed, and the whole hole shall be cored. The core of the subsidence column section can be used for rock and mineral identification, permeability and porosity testing to provide support for the subsequent subsidence column management; Step M3: Based on the exploration and verification results of step 2, if the development of collapse columns has been verified, no less than 3 water-rich and water-conducting exploration holes shall be constructed in the direction of the bottom plate of the underground tunnel; the water pressure of the Cambrian or Ordovician limestone aquifer shall be inferred based on the collapse column area, and water-stop casing shall be installed in the bottom plate holes, and the inclination shall be measured every no more than 10m during the drilling construction; One of the holes ends at the center of the collapse column, vertically to the thin layer of Taiyuan limestone below the thickness of the safety waterproof layer of the bottom plate of the main mining coal seam. In addition, no less than two holes end at the edge of the collapse column, vertically to the thin layer of Taiyuan limestone below the thickness of the safety waterproof layer of the bottom plate of the main mining coal seam. Water pressure tests are carried out after drilling.

5. The integrated well-ground exploration and treatment method for deep subsidence columns according to claim 4 is characterized in that: Specific steps for coal pillar retention or grouting treatment in step 4: Step N1: Determine the scope of the coal pillar of the subsidence column according to the accurate exploration results of the development scope, water richness and water conductivity of the subsidence column in step 3; Step N2: Based on the precise exploration results of the development range, water-richness and water conductivity of the collapse column in step 3, determine the technical solution for grouting treatment of the collapse column; from a safety perspective, for the floor grouting reinforcement project of the collapse column, focus on grouting to form a "water stopper" with a thickness exceeding the thickness of the safe waterproof layer for mining at the working face in the thin layer of Taiyuan Formation limestone at the bottom of the main mining coal seam and its top plate outside the floor damage zone of the working face, and at the same time consider the depth of the floor damage zone of the working face to completely eliminate hidden dangers and ensure safe mining at the working face.

6. The integrated well-ground exploration and treatment method for deep subsidence columns according to claim 5 is characterized in that: The empirical formula for calculating the water-proof coal / rock pillar of the collapse column in step L3 / step M2 / step N1 is as follows: ； In the above formula, L is the width of the coal / rock pillar of the collapse column to prevent water from seeping in / m; K is the safety factor, which ranges from 2 to 5; M is the thickness of the coal seam or the mining height / m; p is the actual head value of the Cambrian or Ordovician limestone aquifer / MPa; Kp is the tensile strength of coal / rock / MPa.

7. The integrated well-ground exploration and treatment method for deep subsidence columns according to claim 5 is characterized in that: The empirical formula for calculating the thickness of the safety waterproof layer in step N2 is: ； In the above formula, t is the thickness of the safety waterproof layer / m; P is the actual water head value of the bottom waterproof layer / MPa; L is the width of the tunnel bottom plate, the working face opening cycle pressure step / m; γ is the average weight of the bottom waterproof layer / MN / m³; K p It is the tensile strength of the bottom plate waterproof layer / MPa.

8. The integrated well-ground exploration and treatment method for deep subsidence columns according to claim 7 is characterized in that: In step N2, the empirical formula for calculating the bottom plate failure zone is: h = 0.7007 + 0.1079L; or h=0.303L 0.8 ;or h=0.0085H+0.1665α+0.1079L-4.3579; In the above formula, h is the depth of the damaged zone of the working face mining floor / m; L is the inclined length of the working face / m; H is the mining depth / m; α is the inclination angle of the coal seam / °.

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