A method for water control and scour prevention in complex structures combining curtain grouting and quantitative fracturing

Abstract

This invention discloses a method for controlling water and preventing erosion in complex geological structures by combining curtain grouting and quantitative fracturing, belonging to the field of coal mine disaster prevention and control technology. The method includes the following steps: S1, microseismic detection and energy identification, deploying a microseismic monitoring system to determine energy accumulation zones; S2, borehole layout and quantitative fracturing preparation, based on the energy accumulation zones identified in step S1, deploying hydraulic fracturing boreholes underground to the energy accumulation zones, and installing a hydraulic fracturing pipeline system within the hydraulic fracturing boreholes; S3, quantitative hydraulic fracturing, continuous microseismic monitoring, and determination of water diversion channel locations; S4, grouting borehole layout, curtain grouting reinforcement, and grouting effect evaluation. This invention significantly improves the proactiveness of complex disaster prevention and control, comprehensively enhancing the mine's disaster resistance and safe mining level in complex geological environments.

Description

Technical Field

[0001] This invention belongs to the field of coal mine disaster prevention and control technology, and in particular relates to a method for controlling water and preventing erosion in complex structures by combining curtain grouting and quantitative fracturing. Background Technology

[0002] During coal mining, areas adjacent to complex geological structures such as faults, collapse columns, and joints often face the dual threat of rockbursts and water inrush disasters. Under the influence of mining disturbance, such structures are prone to activation. For example, the fractured rock mass within a fault may slide, leading to stress concentration and the accumulation of a large amount of energy. Once this energy is suddenly released, it can easily induce dynamic disasters such as rockbursts. At the same time, activation in complex structural areas can lead to the development of micro-fractures that interconnect to form water-conducting channels, creating a hydraulic connection with confined aquifers, thereby triggering water inrush accidents and constituting a typical compound disaster risk.

[0003] Currently, commonly used disaster prevention and control methods on-site mostly focus on post-disaster remediation, such as sealing after a water inrush or conventional grouting reinforcement, lacking the ability to quantitatively identify and proactively prevent energy accumulation processes in structural zones. Furthermore, single technical methods are often insufficient to simultaneously address the combined hazards of rockburst and water inrush; for example, indiscriminate fracturing may exacerbate water conduction risks, while grouting alone cannot effectively release accumulated energy. Existing methods have significant limitations in terms of construction targeting, efficiency, and risk control, and a systematic proactive prevention and control system for combined disasters has not yet been formed. Summary of the Invention

[0004] The purpose of this invention is to provide a method for controlling water and preventing erosion in complex structures by combining curtain grouting and quantitative fracturing, so as to solve the problems existing in the prior art.

[0005] To achieve the above objectives, the present invention provides the following solution: The present invention provides a method for water control and scour prevention in complex structures combining curtain grouting and quantitative fracturing, comprising the following steps: S1. Microseismic detection and energy identification: Deploy a microseismic monitoring system to determine energy accumulation areas; S2. Drill hole layout and quantitative fracturing preparation: Based on the energy accumulation zone identified in step S1, hydraulic fracturing boreholes are laid downhole to the energy accumulation zone, and a hydraulic fracturing pipeline system is laid in the hydraulic fracturing boreholes. S3. Quantitative hydraulic fracturing, continuous microseismic monitoring and determination of water-conducting channel location: Quantitative fracturing is carried out on the target energy accumulation area. During and after fracturing, the energy spectrum and microseismic events in the complex structural area are continuously monitored in real time using the microseismic monitoring system. At the same time, the location of the water-conducting channel is determined by relying on the microseismic data and calculation formula. S4. Grouting borehole layout, curtain grouting reinforcement and grouting effect evaluation: grouting boreholes are laid out to the development position of the water guiding channel, grouting pipelines are arranged in the grouting boreholes, and the grouting pressure is monitored by pressure sensors during the grouting process. When the set final pressure is reached, the grouting is considered complete and the grouting pipelines are withdrawn.

[0006] Optionally, the microseismic monitoring system described in step S1 is installed in the transport roadway or return air roadway of the working face near the fault.

[0007] Optionally, the distance between the microseismic monitoring system and the fault is 30m-50m.

[0008] Optionally, the diameter of the hydraulic fracturing borehole in step S2 is 89mm-110mm.

[0009] Optionally, the hydraulic fracturing pipeline system described in step S2 includes a sealing device and a flow monitoring mechanism.

[0010] Optionally, a hydraulic fracturing pump station is provided in the working face for conducting in-situ stress tests and mechanical experiments on the fault fractured rock mass during the fracturing preparation stage.

[0011] Optionally, microseismic location can be used to pinpoint the development of water-conducting channels within the fault, and connectivity characterizes the likelihood of fractures forming between microseismic events. The calculation formula is as follows: ; In the formula: For rock fracture connectivity; and Represent any two microseismic events and The radius of influence; and Represent any two microseismic events and Spatial coordinates.

[0012] Optionally, a grouting pump station is provided in the working face, and the grouting pump station is connected to the grouting pipeline.

[0013] Optionally, inorganic or organic polymer materials can be used as grouting materials for grouting reinforcement and sealing. A curtain grouting reinforcement can be formed by using porous grouting and multi-stage injection. A grout with a low water-cement ratio can be used, and the grouting pressure should be lower than 70% of the shear strength of the complex structure.

[0014] Optionally, the final pressure is set to 5 MPa.

[0015] This invention discloses the following technical effects: It constructs a collaborative prevention and control system guided by microseismic monitoring and incorporating both quantitative hydraulic fracturing and curtain grouting functions, achieving proactive, precise, and integrated management of combined rockburst and water inrush disasters in complex geological zones. This invention can identify energy accumulation areas and water-conducting channel development locations within complex geological zones in real time, and achieve controllable energy release based on quantitative fracturing, while effectively sealing the water-conducting channels through grouting. Compared to traditional technologies that struggle to simultaneously address rockburst and water inrush prevention, rely heavily on experience in construction, and suffer from insufficient risk awareness, this invention significantly improves the proactiveness of combined disaster prevention and control, comprehensively enhancing the mine's disaster resistance and safe mining level in complex geological environments. Attached Figure Description

[0016] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The embodiments of this application and their descriptions are used to explain this application and do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a schematic diagram of the quantitative hydraulic fracturing process of the present invention; Figure 2 This is a schematic diagram of the curtain grouting process of the present invention; Figure 3 This is a flowchart illustrating the implementation steps of the present invention.

[0017] Figure label: 1. Fault; 2. Microseismic monitoring system; 3. Hydraulic fracturing pump station; 5. Water diversion channel; 6. Quantitative hydraulic fracturing zone; 7. Hydraulic fracturing borehole; 11. Working face; 12. Grouting borehole; 13. Grouting pump station; 14. Grouting area; 15. Energy accumulation zone. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0020] Reference Figures 1 to 3 As shown, this embodiment provides a method for water control and scour prevention in complex structures that combines curtain grouting and quantitative fracturing, including the following steps: S1. Microseismic detection and energy identification: Deploy microseismic monitoring system 2 and identify energy accumulation zone 15; S2. Drilling layout and quantitative fracturing preparation: Based on the energy accumulation zone identified in step S1, hydraulic fracturing boreholes 7 are laid downhole to the energy accumulation zone 15, and a hydraulic fracturing pipeline system is laid in the hydraulic fracturing boreholes 7. S3. Quantitative hydraulic fracturing, continuous microseismic monitoring and determination of the location of water-conducting channel 5. Quantitative fracturing is carried out on the target energy accumulation zone 15. During and after fracturing, the energy spectrum and microseismic events in the complex structural area are continuously monitored in real time by the microseismic monitoring system 2. At the same time, the location of water-conducting channel 5 is determined by relying on microseismic data and calculation formulas. S4. Grouting borehole 12 layout, curtain grouting reinforcement and grouting effect evaluation: grouting borehole 12 is laid out to the development position of water guiding channel 5. Grouting pipeline is arranged in grouting borehole 12. During the grouting process, the grouting pressure is monitored by pressure sensor. When the set final pressure is reached, the grouting is considered complete and the grouting pipeline is withdrawn.

[0021] This invention constructs a collaborative prevention and control system guided by microseismic monitoring and incorporating both quantitative hydraulic fracturing and curtain grouting functions, achieving proactive, precise, and integrated management of combined rockburst and water inrush disasters in complex geological zones. This invention can identify the energy accumulation zone 15 and the development location of water-conducting channels 5 within complex geological areas in real time, and achieve controllable energy release based on quantitative fracturing, while effectively sealing the water-conducting channels 5 through grouting. Compared to traditional technologies that struggle to simultaneously address rockburst and water inrush prevention, rely heavily on experience in construction, and suffer from insufficient risk awareness, this invention significantly improves the proactiveness of combined disaster prevention and control, comprehensively enhancing the mine's disaster resistance and safe mining level in complex geological environments.

[0022] To further optimize the scheme, in step S1, the microseismic monitoring system 2 is installed in the transport roadway or return air roadway of the working face 11 near the fault 1.

[0023] Further optimization of the scheme resulted in a straight-line distance of 30m-50m between the microseismic monitoring system 2 and fault 1.

[0024] To achieve real-time acquisition of microseismic signals, source location, and energy assessment of microseismic events within complex structural regions, this system aims to identify high-energy accumulation zones within complex structural regions, ensuring the accuracy of source location and energy inversion within fault 1. The microseismic monitoring system 2 continuously acquires microseismic signals within fault 1, processes the acquired signals in real time, and identifies the source location, event frequency, magnitude, and energy distribution characteristics. (0 < energy ≤ 10) 4 The microseismic event J is defined as the safety threshold, with 10 4Microseismic events with energy J are defined as a danger threshold. When a local area of ​​fault 1 experiences 2-3 low-frequency danger threshold events, that area is designated as an energy accumulation zone 15. This identification step provides accurate spatial positioning data for subsequent drilling and quantitative fracturing, avoiding blind fracturing.

[0025] Further optimization of the scheme: in step S2, the diameter of the hydraulic fracturing borehole 7 is 89mm-110mm.

[0026] Based on the location of the high-energy accumulation zone 15 identified in step S1, a hydraulic fracturing borehole 7 is drilled downhole to reach the center or boundary of the energy accumulation zone, so as to achieve quantitative hydraulic fracturing of the target area and release the energy of the target area.

[0027] Further optimization of the scheme: In step S2, the hydraulic fracturing pipeline system includes a sealing device and a flow monitoring mechanism.

[0028] The perforator is used to perform hydraulic fracturing in the target area, and the flow monitoring mechanism is used to monitor parameter changes during the hydraulic fracturing process to ensure that the hydraulic fracturing reaches the ideal state.

[0029] The scheme was further optimized by installing a hydraulic fracturing pump station 3 in working face 11, which is used to conduct in-situ stress tests and mechanical experiments on the fractured rock mass of fault 1 during the fracturing preparation stage. During the fracturing preparation stage, in-situ stress tests and mechanical experiments are conducted on the fractured rock mass of fault 1 to determine the direction of the minimum principal stress and the fracture initiation pressure, providing control parameters for quantitative fracturing.

[0030] After the deployment in step S2 is completed, quantitative hydraulic fracturing is performed on the target energy accumulation zone 15. The fracturing process employs a segmented, graded control method, using a pressure stabilization and boosting control mode to keep the injection pressure stable at 0.5–2.0 MPa above the fracture initiation pressure. During hydraulic fracturing, the pressure measuring device in the hydraulic fracturing pipeline system is monitored and recorded in real time. When a sudden pressure drop occurs in the pressure measuring device, it indicates that the fractured rock mass of fault 1 in energy accumulation zone 15 has been fractured. At this point, pressure stabilization and boosting should be stopped to prevent fracturing of the fractured zone of fault 1 outside energy accumulation zone 15, thus achieving quantitative hydraulic fracturing and forming a quantitative hydraulic fracturing zone 6 in energy accumulation zone 15. This allows the fracture to expand in the target direction and fully release the accumulated energy. The fracturing medium can be clear water or viscous water-based fracturing fluid. After the fracturing operation is completed, the distribution of microseismic events, energy changes, and frequency response within fault 1 are continuously monitored using the microseismic monitoring system 2. If monitoring results show that high-energy, low-frequency microseismic events still exist within the energy spectrum of fault 1, it indicates that the local energy has not been fully released. In this case, steps S2-S3 can be repeated to re-fracturing the residual energy zone. This cyclic process continues until microseismic monitoring results show that the accumulated energy has been fully released or has dropped to a predetermined safety threshold, at which point the energy is considered fully released. The development location of water-conducting channels 5 in fault 1 is determined through microseismic localization, and connectivity characterizes the possibility of fracture formation between microseismic events. The calculation formula is: ; In the formula: For rock fracture connectivity; and Represent any two microseismic events and The radius of influence; and Represent any two microseismic events and Spatial coordinates.

[0031] For the connectivity calculation formula, when the connectivity is greater than 1, it can be considered that two micro-fractures are connected to form a fracture. When the connectivity is less than 1, two micro-fractures will not connect to form a fracture. The larger the value, the greater the probability that the micro-fracture will develop into a water-conducting channel 5.

[0032] The scheme has been further optimized. A grouting pump station 13 is installed in the working face 11, and the grouting pump station 13 is connected to the grouting pipeline.

[0033] Further optimize the scheme by using inorganic or organic polymer materials as grouting materials for grouting reinforcement and sealing. Use multi-hole grouting and multi-stage injection to form a curtain grouting reinforcement. Use grout with a low water-cement ratio and the grouting pressure should be lower than 70% of the shear strength of the complex structure.

[0034] The scheme was further optimized, and the final pressure was set to 5MPa.

[0035] A grouting pump station 13 is installed in working face 11. The grouting process involves multi-hole grouting and phased injection to form a continuous and dense sealing curtain of grout in the water-conducting channel 5 and the surrounding rock mass, creating a curtain grouting area 14. To prevent secondary slippage of fault 1 caused by grouting, the grouting pressure should be lower than 70% of the shear strength of fault 1, which is obtained through laboratory mechanical testing. Inorganic cement or organic polymer materials can be used as grouting materials. To ensure good water-blocking ability, a grout with a low water-cement ratio should be used, as its high adhesion can form a dense solidified body, thus reinforcing fault 1 and sealing it. During the grouting process, the grouting pressure is monitored by a pressure sensor. Grouting is considered complete when the set final pressure of 5 MPa is reached, and the grouting pipeline is withdrawn. Combining grouting pressure monitoring and micro-vibration feedback, the grout diffusion range and reinforcement effect are evaluated in real time. When the connectivity calculated by the above formula is less than 1, it indicates that the sealing effect of the water channel 5 is good. If the connectivity is greater than 1, it indicates that the sealing effect of the water channel 5 is not ideal. In this case, step S4 should be repeated. At the same time, the micro-seismic event should be combined to determine whether a new energy accumulation zone 15 has developed during the grouting process. If it has, steps S2-S3 should be repeated to perform hydraulic fracturing on the target area to ensure complete energy release and ensure sealing quality.

[0036] Through the above steps, while achieving the dual objectives of energy release from fault 1 and reinforcement of water-conducting channel 5, the probability of rockburst and water inrush disasters is significantly reduced, forming a comprehensive prevention and control system for both rockburst and water inrush.

[0037] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0038] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for water control and scour prevention in complex structures combining curtain grouting and quantitative fracturing, characterized in that, Includes the following steps: S1. Microseismic detection and energy identification, deploying a microseismic monitoring system (2) and determining energy accumulation areas (15). S2. Drilling layout and quantitative fracturing preparation: Based on the energy accumulation zone identified in step S1, hydraulic fracturing boreholes (7) are laid downhole to the energy accumulation zone (15), and a hydraulic fracturing pipeline system is laid in the hydraulic fracturing boreholes (7). S3, quantitative hydraulic fracturing, continuous microseismic monitoring and determination of the location of the water-conducting channel (5), quantitative fracturing is carried out on the target energy accumulation area (15), and the energy spectrum and microseismic events in the complex structure area are continuously monitored in real time during and after fracturing using the microseismic monitoring system (2), and the location of the water-conducting channel (5) is determined by relying on the microseismic data and through the calculation formula. S4. Grouting borehole (12) layout, curtain grouting reinforcement and grouting effect evaluation. Layout grouting borehole (12) to the development position of water guide channel (5). Arrange grouting pipeline in grouting borehole (12). During the grouting process, the grouting pressure is monitored by pressure sensor. When the set final pressure is reached, the grouting is considered complete and the grouting pipeline is withdrawn.

2. The method for controlling water and preventing erosion in complex structures using combined curtain grouting and quantitative fracturing as described in claim 1, characterized in that: The microseismic monitoring system (2) described in step S1 is installed in the transport roadway or return air roadway of the working face (11) near the fault (1).

3. The method for controlling water and preventing erosion in complex structures by combining curtain grouting and quantitative fracturing according to claim 2, characterized in that: The distance between the microseismic monitoring system (2) and the fault (1) is 30m-50m.

4. The method for controlling water and preventing erosion in complex structures by combining curtain grouting and quantitative fracturing as described in claim 1, characterized in that: The diameter of the hydraulic fracturing borehole (7) in step S2 is 89mm-110mm.

5. The method for controlling water and preventing erosion in complex structures by combining curtain grouting and quantitative fracturing as described in claim 1, characterized in that: The hydraulic fracturing pipeline system described in step S2 includes a sealing device and a flow monitoring mechanism.

6. The method for controlling water and preventing erosion in complex structures by combining curtain grouting and quantitative fracturing as described in claim 2, characterized in that: The working face (11) is equipped with a hydraulic fracturing pump station (3) for conducting in-situ stress tests and mechanical tests on the fractured rock mass of the fault (1) during the fracturing preparation stage.

7. The method for controlling water and preventing erosion in complex structures by combining curtain grouting and quantitative fracturing as described in claim 1, characterized in that: The development location of water-conducting channels (5) in fault (1) is determined by microseismic location. Connectivity characterizes the possibility of cross-linking between microseismic events, and the calculation formula is as follows: ； In the formula: The connectivity of rock fractures; and Represent any two microseismic events and The radius of influence; and Represent any two microseismic events and Spatial coordinates.

8. The method for controlling water and preventing erosion in complex structures using combined curtain grouting and quantitative fracturing as described in claim 2, characterized in that: The working face (11) is provided with a grouting pump station (13), which is connected to the grouting pipeline.

9. The method for controlling water and preventing erosion in complex structures by combining curtain grouting and quantitative fracturing as described in claim 1, characterized in that: Inorganic or organic polymer materials are used as grouting materials for grouting reinforcement and sealing. Multi-hole grouting and multi-stage injection are used to form a curtain grouting reinforcement. A grout with a low water-cement ratio is used, and the grouting pressure should be lower than 70% of the shear strength of the complex structure.

10. The method for controlling water and preventing erosion in complex structures by combining curtain grouting and quantitative fracturing according to claim 1, characterized in that: The final pressure is set to 5 MPa.

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