Weakly cemented overburden strata grouting separation layer water disaster evaluation method, system, device and medium
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHENHUA GUONENG ENERGY GRP
- Filing Date
- 2026-03-19
- Publication Date
- 2026-07-03
Smart Images
Figure CN122333725A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of coal mining safety technology, and in particular to a method, system, equipment and medium for assessing water hazard caused by grouting in weakly cemented overburden. Background Technology
[0002] Weakly cemented overburden is mainly composed of mudstone and siltstone, characterized by poor cementation, low strength, and easy softening and disintegration upon contact with water. Under the disturbance of coal seam mining, weakly cemented overburden is prone to differential settlement, forming interlayer separation spaces (i.e., delamination spaces). At the same time, a large number of water-conducting fractures develop, providing potential channels for the infiltration of delamination water or grouting fluid, which can lead to water inrush and grouting accidents, seriously threatening the safe production of the mine.
[0003] Currently, the most common method used for risk assessment of water hazards in grouting and backfilling of overburden is the improved water inrush coefficient method. This method evaluates water hazard risk by considering the self-weight of the underlying rock strata and the grouting pressure. However, the evaluation criteria retain the evaluation indicators of the floor water inrush coefficient method, that is, for areas with simple structures, when the water inrush coefficient is <0.1Pa / m, the grouting project is considered safe. However, the evolution law of mining-induced fractures in weakly cemented overburden is significantly different from that in conventional mining areas. Therefore, the evaluation criteria of the improved water inrush coefficient method are not entirely applicable to the risk assessment of water hazards caused by grouting delamination under weakly cemented overburden conditions.
[0004] In addition, existing risk assessments of water hazards caused by grouting delamination under weakly cemented overburden conditions often rely on numerical or physical simulations alone. This results in insufficient accuracy of key parameters such as the height of water-conducting fracture zones and the spatial location of delamination, making it difficult to accurately reflect complex geological conditions on site and easily leading to misjudgments of water hazard risks. Summary of the Invention
[0005] The purpose of this invention is to provide a method, system, equipment, and medium for assessing water hazard caused by grouting delamination in weakly cemented overburden, thereby improving the accuracy and reliability of risk assessment for water hazard caused by grouting delamination in weakly cemented overburden.
[0006] To achieve the above objectives, this invention provides a method for assessing water hazard caused by grouting delamination in weakly cemented overburden, comprising: Based on the strata distribution and mechanical parameters of the target weakly cemented overburden, a numerical model and a similarity model of the overburden are constructed. Coal seam excavation simulations were performed on the numerical model and the similar model. The simulation results were analyzed to determine the target grouting separation space height and the water-conducting fracture zone height. Calculate the appropriate grout layer thickness based on the mine's mining height; The safe height is determined based on the height of the water-conducting fracture zone and the appropriate thickness of the grout barrier layer; When the target grout separation space height is less than the safe height, the risk of water damage is determined based on the water conduction and storage characteristic parameters.
[0007] Optionally, the water-conducting and water-storing characteristic parameters include the distribution of the water-conducting fracture network channels in the target weakly cemented overburden, the water storage capacity of the target grouting separation space, and the water inflow reduction coefficient.
[0008] Optionally, when the target grout separation space height is less than the safe height, the water hazard risk assessment is performed based on water conduction and storage characteristic parameters, including: The predicted inflow after reduction is determined based on the water storage capacity of the target grouting separation space and the inflow reduction coefficient. Compare the predicted water inflow with the mine's designed drainage capacity; If the predicted water inflow is less than or equal to the mine's designed drainage capacity, then it is determined that there is no risk of water hazard. If the predicted water inflow is greater than the mine's designed drainage capacity, the risk is determined based on the distribution of the water-conducting fracture network channels. If the water-conducting fracture channel leads to the mining area, it is determined that there is no risk of water hazard. If the water-conducting fissure leads to the working face, it is considered that there is a risk of water damage.
[0009] Optionally, the construction of a numerical model and a similarity model of the overburden based on the strata distribution and mechanical parameters of the target weakly cemented overburden includes: The rock strata distribution of the target weakly cemented overburden is determined based on the geological borehole data of the mine, and a numerical model of the overburden is constructed based on the rock strata distribution; Based on the distribution, lithology, and mechanical parameters of the target weakly cemented overburden, a similar simulation material ratio is set to construct a similar model.
[0010] Optionally, the step of simulating coal seam excavation using the numerical model and the similar model, analyzing the simulation results, and determining the target grouting separation space height and the water-conducting fracture zone height includes: Coal seam excavation simulations were performed using the numerical model and the similar model. According to the preset monitoring plan, images of macroscopic deformation of the overburden and videos of crack propagation of the similar model during the excavation simulation process are collected to obtain the first crack evolution data. The second fracture evolution data is obtained by numerically calculating the data of fracture initiation, development and collapse inside the overburden during the excavation simulation process using the numerical model. By comparing and analyzing the first fracture evolution data with the second fracture evolution data, the spatiotemporal evolution characteristics of the overburden delamination space and the evolution law of the overburden water-conducting fracture network are determined. Based on the spatiotemporal evolution characteristics and the evolution law, the target grouting delamination space height and the water-conducting fracture zone height are determined.
[0011] Optionally, the amount of water stored in the target grouting separation space is determined by the following steps: Based on the simulation results, the height of the target grout separation space is obtained; Based on the morphology of the target grout separation space, the settlement curve of the grout barrier layer is constructed based on the elastic foundation beam theory; Based on the sinking curve, calculate the maximum area of the target grout separation space on the two-dimensional profile; Based on the maximum area and the working face advancement size, determine the amount of water stored in the target grouting separation space.
[0012] Optionally, the inflow reduction factor is calculated based on the density of through fractures in the target weakly cemented overburden, the absorption rate of the grout by the fractured rock mass, the diffusion rate of the grout in the fractured rock mass, and a preset empirical correction factor.
[0013] To achieve the above objectives, the present invention also provides a system for assessing water hazard caused by grouting delamination in weakly cemented overburden, comprising: The model building module is used to construct numerical models and similar models of the overburden based on the strata distribution and mechanical parameters of the target weakly cemented overburden. The first height parameter determination module is used to simulate coal seam excavation using the numerical model and the similar model, analyze the simulation results, and determine the target grouting separation space height and the water-conducting fracture zone height. The second height parameter determination module calculates the appropriate grout layer thickness based on the mine mining height. The third height parameter determination module determines the safe height based on the height of the water-conducting fracture zone and the reasonable thickness of the grout barrier layer; The water hazard risk assessment module is used to assess the water hazard risk based on water conduction and storage characteristic parameters when the target grout separation space height is less than the safe height.
[0014] To achieve the above objectives, the present invention also provides a terminal device, including a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor, wherein the processor executes the computer program to implement the weak cemented overburden grouting delamination water hazard assessment method as described in any of the above claims.
[0015] To achieve the above objectives, the present invention also provides a computer-readable storage medium comprising a stored computer program, wherein, when the computer program is executed, it controls the device containing the computer-readable storage medium to perform the weakly cemented overburden grouting delamination water hazard assessment method as described above.
[0016] Compared with existing technologies, this invention provides a method for assessing water hazards caused by grout delamination in weakly cemented overburden. Firstly, by combining numerical simulation and physical similarity simulation, the damage process of weakly cemented overburden under mining disturbance is analyzed, improving the accuracy of simulation methods and accurately obtaining two key parameters: the target grout delamination space height and the height of the water-conducting fracture zone. Based on this, a reasonable grout barrier thickness calculated according to the mining height is introduced, and together with the water-conducting fracture zone height, a safe height threshold is established, providing a scientific quantitative basis for judging the safety of the grouting layer. When the delamination space height is lower than the safe threshold, water-conducting and water-storage characteristic parameters are further introduced for refined risk assessment, avoiding misjudgments that may result from comparing only the height. This invention provides a water hazard assessment method applicable to weakly cemented overburden conditions, improving the accuracy and reliability of water hazard risk assessment for grout delamination in weakly cemented overburden, providing technical support for the rational selection of grouting layers and safe mining in weakly cemented overburden mining areas, and effectively ensuring safe mine production. Attached Figure Description
[0017] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0018] Figure 1 This is a flowchart of a method for assessing water hazard caused by grouting in weakly cemented overburden, provided in an embodiment of the present invention; Figure 2 This is a schematic diagram illustrating the evolution of water hazard caused by grouting in weakly cemented overburden, according to an embodiment of the present invention. Figure 3 This is a schematic diagram of a grouting delamination spatial mechanical model based on elastic foundation theory provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of a weakly cemented overburden similar model and monitoring scheme provided in an embodiment of the present invention; Figure 5 This is a schematic diagram of a numerical model of weakly cemented overburden provided in an embodiment of the present invention; Figure 6 This is a three-dimensional distribution cloud map of the height of the water-conducting fracture zone as the working face advances, provided by an embodiment of the present invention; Figure 7 These are real-world images of overlying rock fissure development after excavation and three-dimensional distribution cloud maps of fissure fractal dimension provided in the embodiments of the present invention; Figure 8 This is a profile of the spatial development of overlying delamination in the numerical model provided in this embodiment of the invention; Figure 9 This is a curve showing the variation of the maximum separation height with the working face advancement distance provided in this embodiment of the invention; Figure 10 This is another flowchart of a method for assessing water damage caused by grouting in weakly cemented overburden provided in this embodiment of the invention; Figure 11 This is a structural block diagram of a weakly cemented overburden grouting delamination water hazard assessment system provided in an embodiment of the present invention; Figure 12 This is a structural block diagram of a terminal device provided in an embodiment of the present invention. Detailed Implementation
[0019] 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.
[0020] It should be noted that, in the embodiments of the present invention, the grouting delamination of weakly cemented overburden specifically refers to the interlayer delamination space formed by mining under weakly cemented strata conditions, which can be used for grouting reinforcement or as a potential water storage channel, and is the research object of the water hazard assessment of the present invention.
[0021] See Figure 1 , Figure 1 This is a flowchart illustrating a method for assessing water hazard caused by grouting in weakly cemented overburden, according to an embodiment of the present invention. Figure 1 As shown, the method for assessing water hazard caused by grouting in weakly cemented overburden includes steps S1 to S5: Step S1: Based on the rock layer distribution and mechanical parameters of the target weakly cemented overburden, construct a numerical model and a similar model of the overburden; In an optional embodiment, step S1 includes steps S101 to S102: Step S101: Determine the rock strata distribution of the target weakly cemented overburden based on mine geological borehole data, and construct an overburden numerical model based on the rock strata distribution; For example, based on measured data from mine geological boreholes, the strata distribution characteristics of the target weakly cemented overburden are determined. To improve modeling efficiency and computational stability, thin strata with a thickness of less than 1 m and similar lithology can be merged. A numerical model of the overburden is constructed using UDEC (Universal Distinct Element Code, a geotechnical engineering numerical analysis software based on the discrete element method) to reconstruct the layered structure and mechanical properties of the weakly cemented overburden. Then, combining the mechanical parameters (such as compressive strength, tensile strength, and elastic modulus) and thickness distribution data of each overburden stratum, the potential development location of overburden delamination during coal seam excavation is preliminarily predicted, and the potential overburden grouting delamination space is recorded, providing a target basis for subsequent simulation analysis and parameter extraction.
[0022] Step S102: Based on the rock layer distribution, lithology, and mechanical parameters of the target weakly cemented overburden, set the similar simulation material ratio and construct a similar model.
[0023] For example, based on the stratum distribution parameters, lithology, and mechanical parameters of the target weakly cemented overburden after merging processing, a similarity simulation material formulation scheme is determined according to similarity theory. This results in a simulation material that matches the mechanical properties and deformation patterns of the prototype overburden. A similar overburden model is then constructed proportionally using this simulation material to recreate the layered structural characteristics of the target weakly cemented overburden. Furthermore, after the model is constructed, the bearing strata within the overburden can be highlighted, providing a locational basis for determining the stratum location of the target grouting separation space during subsequent coal seam excavation simulations.
[0024] Step S2: Simulate coal seam excavation using the numerical model and the similar model, analyze the simulation results, and determine the target grouting separation space height and the height of the water-conducting fracture zone; In one optional embodiment, step S2 includes steps S201 to S205: Step S201: Simulate coal seam excavation using the numerical model and the similar model; Step S202: According to the preset monitoring plan, collect macroscopic deformation images of the overburden and videos of crack propagation of the similar model during the excavation simulation process to obtain the first crack evolution data; Step S203: Obtain second fracture evolution data by numerically calculating the data of fracture initiation, development and collapse inside the overburden during the excavation simulation process using the numerical model; Step S204: Compare and analyze the first fracture evolution data with the second fracture evolution data to determine the spatiotemporal evolution characteristics of the overburden delamination space and the evolution law of the overburden water-conducting fracture network. Step S205: Determine the target grouting delamination space height and the water-conducting fracture zone height based on the spatiotemporal evolution characteristics and the evolution law.
[0025] See Figure 2 , Figure 2 This is a schematic diagram illustrating the evolution of water hazard caused by grouting in weakly cemented overburden, according to an embodiment of the present invention. Figure 2 As shown, under the disturbance of coal mining, the complete physical process of overburden delamination from spatial formation and water (slurry) storage to the occurrence of water inrush disaster can be divided into three stages: Water storage separation space formation stage: After coal seam mining, the weak cemented overburden loses support and undergoes differential settlement, forming interlayer voids in the overburden, i.e. water storage separation space, which provides a storage carrier for subsequent water accumulation or grouting. At the same time, mining causes the formation of fracture development zones in the lower part of the overburden, providing potential channels for water seepage.
[0026] Separation and water accumulation (grout) stage: Groundwater or grout gradually fills the separation space, and at the same time, the lower fracture space also begins to store water, forming a stable water storage (grout) structure; the poor cementation and low strength of the weakly cemented overburden cause the fractures to develop further, creating conditions for subsequent water conduction.
[0027] Delamination and water inrush stage: When the height of the delamination space is lower than the safe height, the delamination water (slurry) seeps downward along the developed water-conducting fracture zone. If the fracture channel extends to the mining face, it will cause a delamination and water inrush disaster, threatening the safe production of the mine.
[0028] It should be noted that while similarity models can realistically reproduce the macroscopic process of rock fracture, providing a clear and intuitive understanding, their material ratios cannot fully simulate real lithology, and their boundary conditions contain errors. Numerical models, on the other hand, can precisely set mechanical parameters, facilitating the quantitative analysis of internal stress, but as constitutive models of rock masses, they are simplifications of reality and cannot fully simulate complex geological conditions. Therefore, this embodiment of the invention, through comparative analysis, essentially uses the realism of the physical model to verify the computational accuracy of the numerical model, and then uses the quantitative capabilities of the numerical model to compensate for the measurement limitations of the physical model.
[0029] For example, based on the established overburden numerical model and similar model, coal seam excavation simulations were conducted for both types of models to recreate the actual underground mining process. Then, according to the preset monitoring plan, a high-speed camera was used to observe the entire excavation process of the similar model, recording the overburden deformation and instability, and the generation and propagation of fractures, summarizing the spatiotemporal evolution law of overburden fractures under similar simulation conditions. Simultaneously, the excavation process of the numerical model was monitored synchronously to obtain the characteristics of overburden fracture development and the morphology of rock strata collapse and instability, and to analyze the changes in overburden structure and the evolution law of fractures under numerical simulation conditions. Finally, based on the spatiotemporal evolution characteristics of overburden delamination space and the evolution law of water-conducting fracture network after comparative verification, the stable development target grouting delamination space was accurately identified, and its vertical height from the coal seam roof was determined, i.e., the height of the target grouting delamination space; at the same time, the upper limit of the development of the water-conducting fracture zone was clarified, and the height of the water-conducting fracture zone was determined.
[0030] Step S3: Calculate the appropriate thickness of the grout barrier layer based on the mining height of the mine; For example, the formula for calculating the appropriate thickness of the grout barrier is as follows: ; In the formula, The protective layer thickness is in meters (m); M is the mine depth in meters (m).
[0031] Step S4: Determine the safe height based on the height of the water-conducting fracture zone and the reasonable thickness of the grout barrier layer; Preferably, the safety height is the sum of the height of the water-conducting fracture zone and the thickness of the reasonable grout barrier layer.
[0032] It should be noted that the height of the water-conducting fracture zone represents the maximum height of the most developed and water-conducting fractures in the overlying rock after mining, and is the upper limit of the potential channel for water / grout infiltration. The reasonable grout barrier thickness is the minimum thickness of intact rock strata that must be maintained to ensure the isolation effect, preventing the isolation layer from failing due to calculation errors, geological inhomogeneity, or subsequent disturbances. Only when the bottom height of the grouting separation space is greater than the height of the water-conducting fracture zone plus the reasonable grout barrier thickness, a continuous and intact rock barrier exists between the separation space and the water-conducting fracture zone. This barrier effectively prevents water / grout accumulated in the separation from the fracture zone from being conducted to the mining face through the fracture zone, thereby ensuring mining safety. Therefore, the safe height is set as the sum of the water-conducting fracture zone height and the reasonable grout barrier thickness.
[0033] Step S5: When the target grout separation space height is less than the safe height, water hazard risk is determined based on water conduction and storage characteristic parameters.
[0034] In one optional embodiment, the water-conducting and water-storing characteristic parameters include the distribution of water-conducting fracture network channels, fracture penetration, delamination water storage capacity, and inflow reduction factor.
[0035] In one optional embodiment, the amount of water stored in the target grouting separation space is determined by the following steps: Based on the simulation results, the height of the target grout separation space is obtained; Based on the morphology of the target grout separation space, the settlement curve of the grout barrier layer is constructed based on the elastic foundation beam theory; Based on the sinking curve, calculate the maximum area of the target grout separation space on the two-dimensional profile; Based on the maximum area and the working face advancement size, determine the amount of water stored in the target grouting separation space.
[0036] In practice, when constructing the grout separation layer settlement curve based on the elastic foundation beam theory, the maximum height of the target grout separation space, i.e. the maximum vertical dimension, can be used as the calculation benchmark to ensure the accuracy of water storage calculation.
[0037] For example, see Figure 3 , Figure 3 This is a schematic diagram of a grouting delamination spatial mechanical model based on Winkler's elastic foundation theory, provided by an embodiment of the present invention. Figure 2 In the model, the upper thick, hard rock layer acts as a load-bearing beam. Under mining operations, it bends and sinks, separating from the lower rock layer to form a grouting separation space S, which is approximately trapezoidal in shape and serves as a storage carrier for water / grout. The lower overburden is simplified as a Winkler elastic foundation, assuming that the foundation reaction force is proportional to the sinking displacement, providing elastic support for the thick, hard rock layer. The goaf is flanked by solid coal walls, forming the horizontal boundaries of the model, with a goaf width of 2L. W(x) is the sinking curve of the thick, hard rock layer at position x, obtained by the elastic foundation beam theory, and determines the height distribution of the grouting separation space.
[0038] Furthermore, by solving W(x), the settlement curve of the grout barrier is obtained. Combined with the "inverted trapezoidal" shape, the area of the grout separation space can be quantitatively calculated. The calculation formula is as follows: ; In the formula, S represents the maximum subsidence of the grout separation space, in meters; 2L is the width of the goaf, in meters; and h is the thickness of the grout barrier layer, in meters. These are the characteristic parameters of the elastic foundation beam, in m⁻¹. To fully extract the angle; α is the breaking angle; This represents the thickness of the foundation, in meters (m).
[0039] It is worth noting that the embodiments of the present invention combine the elastic foundation beam theory with the results of dual-model simulation to quantify the water storage of the delamination layer, which can improve the accuracy of water storage calculation for the irregular spatial morphology of the delamination layer in weakly cemented overburden.
[0040] In one optional embodiment, the inflow reduction factor is calculated based on the density of through fractures in the target weakly cemented overburden, the absorption rate of the grout by the fractured rock mass, the diffusion rate of the grout in the fractured rock mass, and a preset empirical correction factor.
[0041] For example, based on the simulation results obtained from simulating coal seam excavation using numerical and similar models, the distribution density of through fractures is extracted and determined by analyzing the evolution law of the overburden water-conducting fracture network. Based on engineering experience in weakly cemented overburden mining areas, and considering the lithology, fracturing degree, and grout characteristics of the overburden in the target area, the absorption rate k of the fractured rock mass for the grout is determined to reflect the adsorption capacity of the fractured rock mass for the grouting grout. Based on the mechanical parameters, fracture development characteristics, and engineering experience of the weakly cemented overburden, the diffusion rate D of the grout in the fractured rock mass is determined to characterize the diffusion range of the grout in the fractured rock mass.
[0042] Furthermore, the specific formula for calculating the inflow reduction factor is as follows: ; In the formula, The smaller the value, the better the grouting and sealing effect, and the more obvious the weakening of the overlying rock's water-conducting capacity. The density of through-cracks is expressed in units of cracks / m. 3 , reflects the density of through-flowing water-conducting fissures in the overburden; k is the absorption rate of grout by the fractured rock mass; D is the diffusion rate of grout in the fractured rock mass; This is a preset empirical correction coefficient, which can range from 0.1 to 0.5. It is used to correct the calculation deviation of the formula. Its value directly reflects the quality of the grouting and sealing effect. The larger the value, the better the grouting and sealing effect.
[0043] In an optional embodiment, step S5 includes steps S501 to S506: Step S501: Determine the predicted inflow after reduction based on the water storage capacity of the target grouting separation space and the inflow reduction coefficient. For example, based on the determined target grout separation space water storage volume and the obtained inflow reduction coefficient, the predicted inflow volume of the weakly cemented overburden under grouting is quantitatively calculated according to a preset inflow volume calculation model. This predicted inflow volume represents the maximum amount of water that may infiltrate to the working face through the overburden fracture network under grouting conditions.
[0044] Step S502: Compare the predicted water inflow with the mine's designed drainage capacity; For example, the predicted water inflow is compared with the actual design drainage capacity of the mine as a benchmark threshold.
[0045] Step S503: If the predicted water inflow is less than or equal to the mine's designed drainage capacity, then it is determined that there is no risk of water hazard. For example, if the predicted water inflow is less than or equal to the mine's designed drainage capacity, it means that even if water inflow occurs, the mine's existing drainage system can fully handle it, and the water will not cause safety accidents such as flooding. Therefore, it is determined that there is no risk of water hazard, and grouting mining can be carried out according to the established plan.
[0046] Step S504: If the predicted water inflow is greater than the designed drainage capacity of the mine, the risk is determined based on the distribution of the water-conducting fracture network channels. For example, if the predicted water inflow exceeds the mine's designed drainage capacity, the next step is to refine the risk assessment. At this point, further analysis is needed, taking into account the distribution of the water-conducting fracture network.
[0047] Step S505: If the water-conducting fracture channel leads to the mining area (i.e., the non-mining working face area, such as the coal wall outside the goaf or the surrounding stable rock mass), it means that the water inrush will not directly threaten the mining operation space and the safety of personnel and equipment, but is only the internal water circulation of the mining area, and it is determined that there is no risk of water hazard. Step S506: If the water-conducting fissure channel leads to the working face, it means that the delamination water or grout will directly penetrate to the work site, exceeding the existing drainage capacity, which may easily cause safety accidents such as water inrush and flooding. Therefore, it is determined that there is a risk of water damage, and the grouting parameters need to be adjusted or water damage control measures need to be taken.
[0048] In summary, the present invention provides a method for assessing water hazards caused by grouting delamination in weakly cemented overburden. Firstly, by combining numerical simulation and physical similarity simulation, the damage process of weakly cemented overburden under mining disturbance is analyzed, improving the accuracy of simulation methods and accurately obtaining two key parameters: the target grouting delamination space height and the height of the water-conducting fracture zone. Based on this, a reasonable grout barrier thickness calculated according to the mining height is introduced, and together with the water-conducting fracture zone height, a safe height threshold is established, providing a scientific quantitative basis for judging the safety of the grouting layer. When the delamination space height is lower than the safe threshold, water-conducting and water-storage characteristic parameters are further introduced for refined risk assessment, avoiding misjudgments that may result from comparing only the height. The present invention provides a water hazard assessment method applicable to weakly cemented overburden conditions, improving the accuracy and reliability of water hazard risk assessment for grouting delamination in weakly cemented overburden, providing technical support for the rational selection of grouting layers and safe mining in weakly cemented overburden mining areas, and effectively ensuring safe mine production.
[0049] To further verify the feasibility and engineering applicability of the method of the present invention, this embodiment selects the weakly cemented overburden of a mining face as the research object. The grouting delamination water hazard assessment method for weakly cemented overburden described in this invention is adopted to complete the construction of the overburden similarity model and numerical model, coal seam excavation simulation and simulation result analysis in sequence. In this way, the development law of the water-conducting fracture zone of the weakly cemented overburden of the working face is revealed, and the spatiotemporal evolution characteristics of the delamination space are clarified, providing a reference for water hazard prevention and safe mining in this mining area and similar weakly cemented overburden mining areas.
[0050] First, based on the rock layer distribution and mechanical parameters of the target weakly cemented overburden, a numerical model and a similarity model of the overburden are constructed. See Figure 4 , Figure 4 This is a schematic diagram of a weakly cemented overburden similarity model and monitoring scheme provided in an embodiment of the present invention. Figure 4 As shown, the dimensions of the similar model are 3000 mm in length, 1445 mm in height, and 300 mm in thickness. The model is arranged from bottom to top with B1 coal seam and three layers of thick soft rock (thick soft rock layer 1, thick soft rock layer 2, and thick soft rock layer 3) to simulate and restore the layered structure and mechanical properties of the weakly cemented overburden in the target mining area.
[0051] Specifically, 10 cm × 10 cm yellow grid monitoring points are set on the model surface to quantify the deformation and displacement of the overburden; a high-speed camera is set on the right side to take high-definition pictures and record the process of overburden deformation instability, crack initiation and expansion and delamination space development during the coal seam excavation simulation, so as to provide observation data for subsequent extraction of the evolution law of overburden cracks, delamination space morphology and height distribution.
[0052] See Figure 5 , Figure 5 This is a schematic diagram of a numerical model of weakly cemented overburden provided in an embodiment of the present invention. Figure 5 As shown, the numerical model is used to simulate and recreate the layered structure of the weakly cemented overburden in the target mining area. From bottom to top, it sequentially arranges the B1 coal seam, the basic roof, and multiple thick soft bearing layers, corresponding one-to-one with the rock layer distribution in similar models, ensuring consistency in geological conditions and mechanical boundaries between the two models. The working face advancement direction marked in the model is used to simulate the stress state of the actual coal face and surrounding rock in the field through boundary constraints, realizing the dynamic simulation of the step-by-step excavation process of the coal seam. The numerical model can quantitatively calculate the stress redistribution within the overburden, the fracture initiation and propagation law, the range of rock strata collapse, and the development height of the water-conducting fracture zone. This complements and verifies the intuitive observation results from the similar model, providing quantitative support for subsequent determination of parameters such as the target grouting separation space height, the height of the water-conducting fracture zone, and the separation water storage capacity.
[0053] By comparing and analyzing the macroscopic deformation observation data of similar models with the micromechanical calculation results of numerical models, this embodiment can systematically reveal the failure characteristics of weakly cemented overburden under mining disturbance, the development law of water-conducting fracture zones, and the spatial and temporal evolution characteristics of delamination.
[0054] Specifically, see Figure 6 , Figure 6 This is a three-dimensional distribution cloud map of the height of the water-conducting fracture zone as the working face advances, provided by an embodiment of the present invention. Figure 6 The color scale ranges from 0 to 158.0 m, used to display the spatial distribution characteristics of the height of the water-conducting fracture zone. For example... Figure 6 As shown, the height of the water-conducting fracture zone gradually increases with the advancement distance of the working face, exhibiting an evolutionary pattern of "rapid growth in the early stage and stabilization in the later stage," providing a quantitative basis for determining the height of the water-conducting fracture zone.
[0055] Specifically, see Figure 7 , Figure 7 These are real-world images of overlying rock fissure development after excavation and three-dimensional distribution cloud maps of fissure fractal dimension provided in embodiments of the present invention. Figure 7 The image on the left shows the actual development of overlying rock fissures after excavation of a similar model. The red grid is the monitoring benchmark, and the black lines are mining-induced fissures, showing the macroscopic morphology of fissures from initiation to expansion and penetration, which is consistent with the direction of the working face advance. Figure 7 The right side shows a three-dimensional distribution cloud map of the fractal dimension of the fractures, with the color scale ranging from 0 to 2.0. This reflects the degree of fragmentation and complexity of the overlying fractures. The higher the fractal dimension, the more developed the fractures in the region, providing an indicator for quantitatively evaluating the conductivity of the water-conducting fracture network.
[0056] Specifically, see Figure 8 , Figure 8 This is a profile of the spatial development of overlying delamination in the numerical model provided in this embodiment of the invention. For example... Figure 8 As shown, from bottom to top are the B1 coal seam and multiple layers of weakly cemented rock strata. The enlarged elliptical area clearly shows the interlayer delamination space formed after mining. Its shape is an inverted trapezoid with "thick in the middle and thin at both ends", which is consistent with the subsidence curve shape assumed by the elastic foundation beam theory, thus verifying the rationality of the delamination space shape assumption.
[0057] Specifically, see Figure 9 , Figure 9 This is the curve showing the change of the maximum separation height with the working face advancement distance provided in the embodiments of the present invention. Figure 9 The blue bars represent measured data, and the red curve represents the fitting result (fitting formula). The coefficient of determination R² = 0.95354. Figure 9The results show that the maximum delamination height increases in an S-shape with the advancing distance, with a rapid increase in the initial stage and a gradual stabilization in the later stage, providing a quantitative basis for determining the target grouting delamination space height.
[0058] Further, see Figure 10 ,like Figure 10 As shown, the water hazard assessment process is mainly divided into two core stages: identification of potential water-conducting channels and comprehensive evaluation of delamination water hazards.
[0059] The potential water-conducting channel identification stage is the initial assessment of water hazard risk. Its core is to determine whether there is a possibility of communication between the water-conducting fracture zone and the water-retaining stratum. Through the aforementioned similarity simulation and numerical simulation analysis, the height of the water-conducting fracture zone (conducting height) and the water-retaining stratum were determined. Then, the height of the water-conducting fracture zone and the water-retaining stratum were compared. If the conducting height is less than or equal to the water-retaining stratum, it is determined that there is no risk of water hazard due to stratification, indicating that the water-conducting fracture zone does not reach the water-retaining space and water cannot infiltrate. If the conducting height is greater than the water-retaining stratum, it is determined to be a potential risk of water hazard due to stratification, and the process proceeds to the subsequent comprehensive evaluation stage. (See the red dashed box for the comprehensive evaluation stage of water hazard due to stratification.)
[0060] The comprehensive assessment of delamination water hazards involves a refined evaluation of potential risks. Firstly, based on simulation results and engineering calculations, two core indicators are obtained: fracture penetration and water storage capacity. Combining these indicators, three attenuation effects are considered: fracture compaction and closure, grouting water seepage, and absorption by fractured rock mass. The reduced inflow volume is then calculated and compared with the mine's designed drainage capacity. If the reduced inflow volume is less than or equal to the mine's drainage capacity, there is no risk of delamination water hazards, indicating that the mine's drainage system can handle potential water inflow. If the reduced inflow volume is greater than the mine's drainage capacity, the area through which the water inflow channel connects needs further investigation. Through numerical simulation and similar simulation results, the final area of the water inflow channel is determined. If the channel leads to the goaf, there is no risk of delamination water hazards, indicating that the water only circulates within the goaf and does not threaten operational safety. If the channel leads to the working face, it is considered a delamination water hazard, indicating that water will directly enter the working space, requiring preventative measures.
[0061] Based on the above method items, the present invention provides corresponding system items embodiments.
[0062] See Figure 11 , Figure 11 This is a structural block diagram of a water hazard assessment system for grouting delamination in weakly cemented overburden provided in an embodiment of the present invention. The water hazard assessment system for grouting delamination in weakly cemented overburden includes: Model building module 21 is used to build a numerical model and a similar model of the overburden based on the rock layer distribution and mechanical parameters of the target weakly cemented overburden. The first height parameter determination module 22 is used to simulate coal seam excavation using the numerical model and the similar model, analyze the simulation results, and determine the target grouting separation space height and the water-conducting fracture zone height. The second height parameter determination module 23 calculates the reasonable grout layer thickness based on the mine mining height. The third height parameter determination module 24 determines the safe height based on the height of the water-conducting fracture zone and the thickness of the reasonable grout barrier layer; The water hazard risk assessment module 25 is used to assess the water hazard risk based on water conduction and storage characteristic parameters when the target grout separation space height is less than the safe height.
[0063] In one optional embodiment, the water hazard risk assessment module 25 is used for: The predicted inflow after reduction is determined based on the water storage capacity of the target grouting separation space and the inflow reduction coefficient. Compare the predicted water inflow with the mine's designed drainage capacity; If the predicted water inflow is less than or equal to the mine's designed drainage capacity, then it is determined that there is no risk of water hazard. If the predicted water inflow is greater than the mine's designed drainage capacity, the risk is determined based on the distribution of the water-conducting fracture network channels. If the water-conducting fracture channel leads to the mining area, it is determined that there is no risk of water hazard. If the water-conducting fissure leads to the working face, it is considered that there is a risk of water damage.
[0064] In one alternative embodiment, the model building module 21 is configured to: The rock strata distribution of the target weakly cemented overburden is determined based on the geological borehole data of the mine, and a numerical model of the overburden is constructed based on the rock strata distribution; Based on the distribution, lithology, and mechanical parameters of the target weakly cemented overburden, a similar simulation material ratio is set to construct a similar model.
[0065] In one alternative embodiment, the first height parameter determining module 22 is configured to: Coal seam excavation simulations were performed using the numerical model and the similar model. According to the preset monitoring plan, images of macroscopic deformation of the overburden and videos of crack propagation of the similar model during the excavation simulation process are collected to obtain the first crack evolution data. The second fracture evolution data is obtained by numerically calculating the data of fracture initiation, development and collapse inside the overburden during the excavation simulation process using the numerical model. By comparing and analyzing the first fracture evolution data with the second fracture evolution data, the spatiotemporal evolution characteristics of the overburden delamination space and the evolution law of the overburden water-conducting fracture network are determined. Based on the spatiotemporal evolution characteristics and the evolution law, the target grouting delamination space height and the water-conducting fracture zone height are determined.
[0066] It should be noted that the weakly cemented overburden grouting delamination water hazard assessment system provided in this embodiment of the invention is used to execute all the process steps of the weakly cemented overburden grouting delamination water hazard assessment method in the above embodiment. The working principles and beneficial effects of the two are one-to-one, so they will not be described again.
[0067] This invention also provides a terminal device, such as... Figure 4 The diagram shown is a structural block diagram of a preferred embodiment of a terminal device provided by the present invention. The terminal device includes a processor 31, a memory 32, and a computer program stored in the memory 32 and configured to be executed by the processor 31. When the processor 31 executes the computer program, it implements the weak cemented overburden grouting delamination water hazard assessment method as described in any of the above embodiments.
[0068] In addition, embodiments of the present invention also provide a computer-readable storage medium, the computer-readable storage medium including a stored computer program, wherein, when the computer program is executed, it controls the device where the computer-readable storage medium is located to perform the weak cemented overburden grouting delamination water hazard assessment method as described in any of the above embodiments.
[0069] When the processor 31 executes the computer program, it implements the steps in the above-described embodiments of the method for assessing water damage caused by grouting separation in weakly cemented overburden, for example... Figure 1 All steps of the weakly cemented overburden grouting delamination water hazard assessment method shown. Alternatively, when the processor 31 executes the computer program, it implements the functions of each module in the above-described weakly cemented overburden grouting delamination water hazard assessment system embodiment, for example... Figure 3 The functions of each module in the weakly cemented overburden grouting delamination water hazard assessment system are shown.
[0070] Preferably, the computer program can be divided into one or more modules / units, which are stored in the memory 32 and executed by the processor 31 to complete the present invention. The one or more modules / units can be a series of computer program instruction segments capable of performing specific functions, which describe the execution process of the computer program in the terminal device.
[0071] The processor 31 can be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor, or the processor 31 can be any conventional processor. The processor 31 is the control center of the terminal device, connecting various parts of the terminal device through various interfaces and lines.
[0072] The memory 32 mainly includes a program storage area and a data storage area. The program storage area can store the operating system, applications required for at least one function, etc., and the data storage area can store related data, etc. In addition, the memory 32 can be a high-speed random access memory, or a non-volatile memory, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, and a flash card, etc., or the memory 32 can also be other volatile solid-state storage devices.
[0073] It should be noted that the aforementioned terminal devices may include, but are not limited to, processors and memory, as will be understood by those skilled in the art. Figure 4 The structural block diagram shown is merely a structural example of the terminal device described above and does not constitute a limitation on the structure of the terminal device. The terminal device may include more or fewer components than shown, or combine certain components, or use different components.
[0074] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.
Claims
1. A method for assessing water hazard caused by grouting delamination in weakly cemented overburden, characterized in that, include: Based on the strata distribution and mechanical parameters of the target weakly cemented overburden, a numerical model and a similarity model of the overburden are constructed. Coal seam excavation simulations were performed on the numerical model and the similar model. The simulation results were analyzed to determine the target grouting separation space height and the water-conducting fracture zone height. Calculate the appropriate grout layer thickness based on the mine's mining height; The safe height is determined based on the height of the water-conducting fracture zone and the appropriate thickness of the grout barrier layer; When the target grout separation space height is less than the safe height, the risk of water damage is determined based on the water conduction and storage characteristic parameters.
2. The method for assessing water hazard caused by grouting delamination in weakly cemented overburden as described in claim 1, characterized in that, The water-conducting and water-storing characteristic parameters include the distribution of the water-conducting fracture network channels in the target weakly cemented overburden, the water storage capacity of the target grouting separation space, and the water inflow reduction coefficient.
3. The method for assessing water hazard caused by grouting delamination in weakly cemented overburden as described in claim 2, characterized in that, When the target grout separation space height is less than the safe height, the water hazard risk is determined based on water conduction and storage characteristic parameters, including: The predicted inflow after reduction is determined based on the water storage capacity of the target grouting separation space and the inflow reduction coefficient. Compare the predicted water inflow with the mine's designed drainage capacity; If the predicted water inflow is less than or equal to the mine's designed drainage capacity, then it is determined that there is no risk of water hazard. If the predicted water inflow is greater than the mine's designed drainage capacity, the risk is determined based on the distribution of the water-conducting fracture network channels. If the water-conducting fracture channel leads to the mining area, it is determined that there is no risk of water hazard. If the water-conducting fissure leads to the working face, it is considered that there is a risk of water damage.
4. The method for assessing water hazard caused by grouting delamination in weakly cemented overburden as described in claim 1, characterized in that, Based on the rock strata distribution and mechanical parameters of the target weakly cemented overburden, a numerical model and a similarity model of the overburden are constructed, including: The rock strata distribution of the target weakly cemented overburden is determined based on the geological borehole data of the mine, and a numerical model of the overburden is constructed based on the rock strata distribution; Based on the distribution, lithology, and mechanical parameters of the target weakly cemented overburden, a similar simulation material ratio is set to construct a similar model.
5. The method for assessing water hazard caused by grouting delamination in weakly cemented overburden as described in claim 1, characterized in that, The process of simulating coal seam excavation using the numerical model and the similar model, analyzing the simulation results, and determining the target grouting separation space height and the water-conducting fracture zone height includes: Coal seam excavation simulations were performed using the numerical model and the similar model. According to the preset monitoring plan, images of macroscopic deformation of the overburden and videos of crack propagation of the similar model during the excavation simulation process are collected to obtain the first crack evolution data. The second fracture evolution data is obtained by numerically calculating the data of fracture initiation, development and collapse inside the overburden during the excavation simulation process using the numerical model. By comparing and analyzing the first fracture evolution data with the second fracture evolution data, the spatiotemporal evolution characteristics of the overburden delamination space and the evolution law of the overburden water-conducting fracture network are determined. Based on the spatiotemporal evolution characteristics and the evolution law, the target grouting delamination space height and the water-conducting fracture zone height are determined.
6. The method for assessing water hazard caused by grouting delamination in weakly cemented overburden as described in claim 2, characterized in that, The water storage capacity of the target grouting separation space is determined by the following steps: Based on the simulation results, the height of the target grout separation space is obtained; Based on the morphology of the target grout separation space, the settlement curve of the grout barrier layer is constructed based on the elastic foundation beam theory; Based on the sinking curve, calculate the maximum area of the target grout separation space on the two-dimensional profile; Based on the maximum area and the working face advancement dimension, determine the amount of water stored in the target grouting separation space.
7. The method for assessing water hazard caused by grouting delamination in weakly cemented overburden as described in claim 2, characterized in that, The inflow reduction factor is calculated based on the density of through fractures in the target weakly cemented overburden, the absorption rate of the grout by the fractured rock mass, the diffusion rate of the grout in the fractured rock mass, and a preset empirical correction factor.
8. A system for assessing water hazard caused by grouting delamination in weakly cemented overburden, characterized in that, include: The model building module is used to construct numerical models and similar models of the overburden based on the strata distribution and mechanical parameters of the target weakly cemented overburden. The first height parameter determination module is used to simulate coal seam excavation using the numerical model and the similar model, analyze the simulation results, and determine the target grouting separation space height and the water-conducting fracture zone height. The second height parameter determination module calculates the appropriate grout layer thickness based on the mine mining height. The third height parameter determination module determines the safe height based on the height of the water-conducting fracture zone and the reasonable thickness of the grout barrier layer; The water hazard risk assessment module is used to assess the water hazard risk based on water conduction and storage characteristic parameters when the target grout separation space height is less than the safe height.
9. A terminal device, characterized in that, The system includes a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor, wherein the processor, when executing the computer program, implements the water hazard assessment method for grouting delamination of weakly cemented overburden as described in any one of claims 1 to 7.
10. A computer-readable storage medium, characterized in that, The computer-readable storage medium includes a stored computer program, wherein, when the computer program is executed, it controls the device containing the computer-readable storage medium to perform the water hazard assessment method for grouting delamination of weakly cemented overburden as described in any one of claims 1 to 7.