In-situ water-retaining grouting modification and optimization method for floor
By acquiring hydrogeological parameters and identifying water-conducting areas in the foundation, a low-permeability barrier was constructed outside the mining-affected area by using directional drilling and segmented injection of modified grout. This solved the problem of water inrush in the foundation of deep, highly confined aquifers, and achieved safe and efficient water hazard control and water-conserving mining.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CCTEG COAL MINING RES INST
- Filing Date
- 2026-04-13
- Publication Date
- 2026-07-14
AI Technical Summary
In existing technologies, the treatment of water inrush or continuous water inrush in mining areas threatened by deep, high-pressure aquifers is ineffective. Underground drainage and pressure reduction are costly, and local drilling and grouting in the mine are difficult to form a continuous water barrier, resulting in repeated water flow around the surface.
By acquiring hydrogeological parameters, identifying abnormal water-conducting areas and dominant water channels in the foundation, and using directional drilling to inject modified grout in stages, a low-permeability modified barrier is constructed outside the range affected by mining-induced damage. Combined with dynamic monitoring to adjust the modification range and parameters, precise water control and water conservation are achieved.
Precisely delineate the water diversion area, rapidly reduce water inflow, construct a long-term water barrier, ensure the safety and economy of mining, avoid water resource damage, and achieve a synergistic effect of water hazard prevention and water-conserving mining.
Smart Images
Figure CN122383265A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of underground mine water hazard prevention and green mining technology, specifically to an in-situ water-retaining grouting modification and optimization method for the foundation plate. Background Technology
[0002] In mining areas threatened by deep, highly confined aquifers, severe floor water inrushes or continuous water surges often occur during the working face mining process. Because multiple layers of aquifers generally exist beneath the floor, often accompanied by natural water-conducting structures such as concealed faults, concentrated fracture zones, or karst channels, the floor fractures caused by mining disturbances easily communicate with these natural structures, thus establishing a long-term fluid supply channel between the deep aquifer and the goaf.
[0003] In existing technologies, two methods are typically used to manage this type of water hazard: one is underground drainage and pressure reduction, which involves extracting large amounts of groundwater to reduce the pressure of the aquifer. However, this not only leads to high drainage costs but also causes regional water level drops, damaging the water resource environment. The other is localized drilling and grouting to block water in the well. However, due to the limited working space and borehole length in the well, this method can often only achieve "point-like" sealing and is difficult to form a continuous water barrier in space. This causes the water flow to bypass under mining pressure, and the water inrush control effect is prone to recurrence. Summary of the Invention
[0004] This application provides an in-situ water-retaining grouting modification and optimization method for the base plate, which solves the problem of poor water damage control effect of the base plate in the prior art, increases the equivalent water-blocking thickness of the base plate, and realizes precise water control and water retention synergy in the treatment and water retention of the base plate of the working face.
[0005] A method for in-situ water-retaining grouting modification and optimization of a foundation slab according to an embodiment of the first aspect of this application includes the following steps: Obtain the basic hydrogeological parameters of the target working face and its underlying aquifers, and delineate the target area for bottom plate water hazard investigation based on the basic parameters. For the target area, a combination of physical detection and verification methods was used to delineate the three-dimensional boundary of the abnormal water-conducting area of the bottom plate; Based on hydrodynamic response characteristic analysis and hydrochemical characteristic identification, the dominant water channel is identified for the three-dimensional boundary of the abnormal water-conducting area. The water source composition and main recharge aquifer of the working face water inflow are determined, as well as the spatial characteristics and water-conducting properties of the dominant water channel. Based on the water source composition and the water-conducting properties of the main water channel, pre-reinforcement grouting materials and injection parameters are matched; according to the matched and determined grouting materials and injection parameters, in-situ pre-reinforcement and initial interception are carried out for the abnormal water-conducting area and the identified main water channel. Based on the spatial location of the main recharge aquifer, the impact range of the bottom plate mining damage caused by the working face, and the spatial characteristics of the main water channel, the target modified layer is determined to be outside the impact range of the mining damage and located above the main recharge aquifer; a well site is arranged on the ground and directional drilling is carried out; Segmented injection modification is carried out along the horizontal branch section of the directional borehole to construct a low-permeability modified barrier within the target modified layer; Establish a dynamic monitoring and evaluation system covering working face water inflow, aquifer water pressure and modified barrier status, and iteratively adjust the subsequent modification range or injection parameters based on monitoring feedback data.
[0006] According to one embodiment of this application, the physical detection includes at least one of channel wave seismic exploration, three-dimensional seismic exploration, transient electromagnetic detection, and direct current electrical resistivity tomography.
[0007] According to one embodiment of this application, the verification probe includes: Verification boreholes are arranged within the abnormal water-conducting area identified by physical exploration. By acquiring the water penetration depth, original water inflow, and water pressure data of the verification boreholes, and combining them with the spatial images from physical exploration, the spatial geometry of the concentrated fracture development zone and karst channels within the abnormal water-conducting area of the base plate is determined.
[0008] According to one embodiment of this application, identifying the dominant water channel, determining the water source composition and main recharge aquifer of the working face water inflow, and the spatial characteristics and water-conducting properties of the dominant water channel include: Conduct single-hole or multi-hole pumping tests to obtain the water level rise and fall response characteristics between different aquifers; Background water samples from the aquifer and water samples from the outlet point of the working face are collected. At least one of the following methods is used: water chemical composition comparison, characteristic ion molar ratio analysis, and hydrogen-oxygen isotope relationship analysis to identify the fluid path through which the deep aquifer supplies water to the working face via the abnormal water-conducting area.
[0009] According to one embodiment of this application, the in-situ pre-reinforcement and initial interception include: The grouting holes are sealed by pressure injection using a multi-stage sealing structure. The multi-stage sealing structure is equipped with at least two-stage casings according to the stratum exposed by the grouting hole and the stability of the surrounding rock. When the grouting hole enters the influence range of a high-pressure aquifer, an additional inlet casing is added to form a three-stage or higher sealing structure.
[0010] According to one embodiment of this application, the in-situ pre-reinforcement and initial interception use cement-based grout or clay composite grout, and are controlled by a combination of pumping pressure and injection flow rate; at the end of the injection, the injection flow rate is reduced to a set threshold, and the injection pressure is increased to the design final pressure and maintained for a preset time, after which the reinforcement is determined to be complete.
[0011] According to one embodiment of this application, determining the target modified layer located outside the mining-induced damage area of the working face and above the main recharge aquifer includes: By establishing a rock stratum failure mechanics model or using microseismic measurement data, the maximum development depth of the floor failure zone caused by the mining face is determined. Combined with the spatial characteristics of the identified dominant water channels, the target modified stratum is set below the maximum development depth. The target modified stratum is a limestone or sandstone layer with structural bearing capacity and good injectability.
[0012] According to one embodiment of this application, the planar arrangement range and spacing of the horizontal branch segments are determined based on the estimated diffusion radius of the slurry within the target modified layer: the envelope range of the horizontal branch segments covers the entire distribution range of the abnormal water-conducting area and the dominant water channel, and the planar projection distance between adjacent branch segments is no greater than twice the estimated diffusion radius of the slurry.
[0013] According to one embodiment of this application, the directional drilling includes: By using drilling sensors to obtain physical response parameters of the rock strata at the bottom of the borehole, the lithological boundary between the target modified layer and its adjacent aquitard is identified, and the horizontal branch segment is controlled to always extend within the target modified layer by adjusting the tool face angle of the drill string.
[0014] According to one embodiment of this application, the iterative adjustment of the subsequent modification range or injection parameters based on monitoring feedback data includes: When the monitored water inflow or the rise in the water level of the replenishment source does not meet expectations, tree-shaped short branch holes are added laterally to the original horizontal branch section to supplement the local weak zones of the modified barrier with injection.
[0015] The above-described one or more technical solutions in the embodiments of this application have at least one of the following technical effects: This application's in-situ water-retaining grouting modification and optimization method for the foundation slab, through parameter acquisition and physical detection combined with verification exploration, accurately delineates the three-dimensional boundary of abnormal water-conducting areas in the foundation slab, eliminating blind spots in treatment. Based on hydrodynamic response and feature identification, it scientifically determines the water source composition, the main recharge aquifer, and the spatial characteristics and water-conducting properties of the dominant water channel, ensuring precise targeting of the main recharge aquifer and water-conducting path. Through in-situ pre-reinforcement and initial interception, the water inflow at the working face is rapidly reduced, ensuring the safety of initial operations. Using directional drilling with horizontal branch sections for segmented injection, a low-permeability modified barrier is constructed, significantly increasing the equivalent water-blocking thickness of the foundation slab and cutting off the recharge source, achieving water-retaining mining under high stability.
[0016] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description
[0017] To more clearly illustrate the technical solutions in the embodiments or related technologies of this application, the accompanying drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. 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 illustrating the in-situ water-retaining grouting modification and optimization method for the base plate provided in this application.
[0019] Figure 2 This is a schematic diagram of the directional drilling structure in the in-situ water-retaining grouting modification and optimization method for the base plate provided in this application. Detailed Implementation
[0020] The embodiments of this application will be described in further detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this application, but should not be used to limit the scope of this application.
[0021] In the description of the embodiments of this application, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.
[0022] In the description of the embodiments of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application based on the specific circumstances.
[0023] In the embodiments of this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.
[0024] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the embodiments of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.
[0025] A method for in-situ water-retaining grouting modification and optimization of the base plate according to an embodiment of the first aspect of this application, such as... Figure 1The process includes the following steps: obtaining the basic hydrogeological parameters of the target working face and its underlying aquifers; delineating the target area for bottom water hazard investigation based on these parameters; delineating the three-dimensional boundary of the abnormal water-conducting area of the bottom plate using a combination of physical detection and verification exploration within the target area; identifying the dominant water channel based on hydrodynamic response characteristic analysis and hydrochemical characteristic identification, determining the water source composition and main recharge aquifer of the working face, as well as the spatial characteristics and water-conducting properties of the dominant water channel; matching pre-reinforcement grouting materials and injection parameters based on the water source composition and the water-conducting properties of the dominant water channel; and implementing in-situ pre-reinforcement and initial interception of the abnormal water-conducting area and the identified dominant water channel according to the matched grouting materials and injection parameters. The process involves several steps: First, reduce the water inflow at the working face. Second, based on the spatial location of the main recharge aquifer, the impact range of mining-induced damage to the floor slab caused by working face extraction, and the spatial characteristics of the dominant water channel, determine the target modified layer located outside the mining-induced damage range and above the main recharge aquifer. Third, establish a well site on the surface and construct directional boreholes, extending them within the target modified layer to form at least one horizontal branch. Fourth, implement segmented injection modification along the horizontal branch of the directional boreholes, constructing a low-permeability modified barrier within the target modified layer to increase the equivalent water-blocking thickness of the floor slab and cut off the recharge path of the main recharge aquifer through the dominant water channel. Fifth, establish a dynamic monitoring and evaluation system covering working face water inflow, aquifer water pressure, and the modified barrier status, iteratively adjusting the subsequent modification range or injection parameters based on monitoring feedback data. The structural diagram of the directional borehole is shown below. Figure 2 As shown.
[0026] The in-situ water-retaining grouting modification and optimization method for the foundation plate adopts a phased and progressive treatment logic. First, it uses multi-dimensional exploration to understand the basic laws of water hazard occurrence and avoids the cost waste caused by indiscriminate treatment. Then, it controls the risk of immediate water inrush through pre-interception measures to provide safe conditions for subsequent operations. The core link is to build a long-term water barrier outside the scope of mining damage to cut off the aquifer recharge path from the source. Finally, it achieves closed-loop optimization of the treatment plan through a dynamic monitoring system, which adapts to the dynamic changes of foundation plate stress during mining and takes into account both water hazard prevention and control and groundwater resource protection.
[0027] This method transforms the management of water hazards in the foundation from passive treatment to proactive prevention and control. Precise delineation of the water-conducting area eliminates the blindness of treatment and significantly reduces the amount of ineffective grouting. Pre-reinforcement quickly controls the risk of water inrush and ensures the continuity of mining operations. The modified barrier constructed outside the mining-affected area cuts off the aquifer recharge path at the source and avoids damage to the water-blocking structure caused by mining. This achieves synergy between water hazard prevention and control and water-conserving mining, greatly improving the safety and economy of working face mining.
[0028] According to one embodiment of this application, physical detection includes at least one of channel wave seismic exploration, three-dimensional seismic exploration, transient electromagnetic detection, and direct current electrical resistivity tomography.
[0029] In practical applications, single or combined detection methods can be flexibly selected according to the geological conditions of the working face, construction space, and detection accuracy requirements. Different methods can achieve multi-dimensional identification of differences in rock strata properties, development of water-conducting fractures, and water body occurrence, making up for the accuracy limitations and application scenario shortcomings of single detection methods.
[0030] According to one embodiment of this application, the verification exploration includes: arranging verification boreholes in the abnormal water-conducting area identified by physical exploration, and determining the spatial geometry of concentrated fracture development zones and karst channels in the abnormal water-conducting area of the base plate by acquiring the water penetration depth, original water inflow and water pressure data of the verification boreholes and combining them with the spatial images of physical exploration.
[0031] By deploying verification boreholes in the initially identified anomalous areas, actual hydrogeological data of the rock strata can be directly obtained. Combined with the spatial imagery results of physical exploration, the anomalous areas can be accurately located and their morphology can be characterized, solving the problem of multiple interpretations in the physical exploration results. At the same time, the actual development parameters of the water-conducting structures can be obtained, providing a precise design basis for subsequent sealing and treatment.
[0032] According to one embodiment of this application, identifying the dominant water channel, determining the water source composition and main recharge aquifer of the working face, and the spatial characteristics and water-conducting properties of the dominant water channel, includes: conducting single-hole or multi-hole pumping tests to obtain the water level rise and fall response characteristics between different aquifers; collecting background water samples from the aquifer and water samples from the working face outlet, and using at least one of water chemical composition comparison, characteristic ion molar ratio analysis, and hydrogen-oxygen isotope relationship analysis to identify the fluid path of deep aquifers recharging to the working face through abnormal water-conducting areas.
[0033] When comparing water chemical composition: A routine full water chemical analysis can be performed simultaneously on background water samples from the aquifer and inflow water samples from the working face, detecting components including K... + Na + Ca 2+ Mg 2+ Isocations, Cl - SO4 2- HCO3 - Core hydrochemical indicators, including anions, total dissolved solids, pH value, and total hardness, are used to establish a unique hydrochemical fingerprint database for each aquifer based on the analysis results. Then, the data of each indicator of the inrush water sample are compared and matched with the fingerprint database one by one. Based on the matching results, the potential source aquifer range of the inrush water at the working face is preliminarily determined.
[0034] When using characteristic ion molar ratio analysis: the molar concentration ratio of characteristic anions and cations in the background water sample of the aquifer and the inflow water sample of the working face can be calculated. Based on the calculation results of the background water samples of each aquifer, the molar ratio characteristic intervals corresponding to different aquifers are first calibrated and established. Then, the calculated molar ratio value of the inflow water sample is accurately matched with the characteristic interval. This can effectively distinguish aquifers with similar hydrochemical types that are difficult to identify by conventional analysis. At the same time, the water-rock interaction characteristics of groundwater in the migration process can be inverted based on the change law of molar ratio, which helps to determine the actual migration path of the fluid.
[0035] When using hydrogen and oxygen isotope relationship analysis: Hydrogen and oxygen stable isotope tests can be performed on background water samples from the aquifer and inflow water samples from the working face to obtain the δD and δ¹⁴ ions in the water samples. 18 By combining the specific composition characteristics of O with the test results, the unique isotopic characteristic value range of each aquifer is determined. The isotopic characteristic value of the water inflow sample is matched with this value range. For scenarios with mixed recharge from multiple aquifers, the proportion of different aquifers to the water inflow at the working face can be quantitatively calculated through the isotopic end-member mixing model, and finally the main recharge aquifer of the water inflow at the working face can be accurately identified.
[0036] By conducting pumping tests to obtain the hydrodynamic response characteristics between aquifers, the strength of the hydraulic connection between aquifers can be determined. By using hydrochemical and isotopic analysis methods, the source aquifers and fluid migration paths of the inrush water can be accurately identified. The two methods are mutually verified, which can accurately grasp the source of water supply and the spatial distribution and water-conducting capacity of the main water channels at the working face, providing a core basis for subsequent targeted treatment.
[0037] The above methods, combining hydrodynamic testing and hydrochemical identification, achieve precise dual identification of the water source and the water-conducting channel. This effectively eliminates interference from non-dominant aquifers and accurately pinpoints the main recharge source and the water-conducting channel. The clear spatial characteristics and water-conducting properties of the dominant water channel can avoid targeting deviations in subsequent treatment, significantly reduce ineffective treatment work, and provide core basis for the selection of the modified barrier's stratum and range design, ensuring the effectiveness of the water-blocking barrier construction.
[0038] According to one embodiment of this application, in-situ pre-reinforcement and initial interception include: pressure injection sealing of grouting holes using a multi-stage sealing structure; the multi-stage sealing structure is equipped with at least two-stage casings according to the stratum exposed by the grouting hole and the stability of the surrounding rock; when the grouting hole enters the influence range of a high-pressure aquifer, an additional inlet casing is added to form a three-stage or higher sealing structure.
[0039] By using two or more casing layers, different rock strata can be sealed in layers. Increasing the casing layer to target the influence range of high-confined aquifers can effectively improve the structural stability of the grouting hole and avoid safety risks such as grout leakage from the hole, casing detachment, and water inrush during the grouting process.
[0040] A graded sealing structure adapted to geological conditions can significantly improve the structural stability and sealing reliability of grouting holes, effectively avoiding safety accidents such as water inrush and grout leakage during the grouting process of high-pressure aquifers; the layered sealing structure can achieve precise grouting of the target layer, avoid grout leakage into non-target layers and waste, while ensuring the effective transmission of grouting pressure, improving the sealing and reinforcement effect of abnormal water-conducting areas, and quickly achieving the goal of initial interception.
[0041] It should be noted that grouting holes are used in the in-situ pre-reinforcement stage of step S4, while directional drilling is used in the long-term barrier construction stages of steps S5 and S6. Grouting holes are used to seal the delineated abnormal water-conducting areas and main water channels in a point-like or area-like manner to quickly reduce the water inflow at the working face. This is an early-stage emergency prevention and control measure and a proactive risk management measure. Grouting holes are mainly vertical holes and small-angle inclined holes with shallow drilling depth, only needing to penetrate to the target abnormal water-conducting layer. The core design is a multi-stage casing isolation structure. Directional drilling is used to construct long-distance horizontal branch sections, building a continuous low-permeability modified barrier covering the entire working face. This cuts off the long-term recharge path of the main aquifer from the source and is a core stage for long-term remediation and water-conserving extraction. A special structure of "vertical hole section + directional drilling section + long-distance horizontal branch section" can be adopted. The drilling depth is large, requiring precise penetration of the overburden and stable rock strata. The trajectory is controlled throughout the drilling process. The core design is that the horizontal branch section extends within the target modified layer.
[0042] According to one embodiment of this application, in-situ pre-reinforcement and initial interception use cement-based grout or clay composite grout, and are jointly controlled by two indicators: pumping pressure and injection flow rate. At the end of the injection, the injection flow rate is reduced to a set threshold, and the injection pressure is increased to the design final pressure and maintained for a preset time, after which the reinforcement is determined to be complete.
[0043] The matching rules for grouting materials and injection parameters are as follows: clay composite grout is matched for high-flow karst water inrush scenarios, and cement-based grout is matched for fracture-type water inrush scenarios; the pumping pressure and injection flow rate are adjusted according to the water-conducting properties of the dominant water channel to ensure the accuracy of grouting and sealing. The above-mentioned grout types can adapt to the grouting needs of different rock strata, taking into account both water-blocking performance and reinforcement strength, to achieve effective sealing of abnormal water-conducting areas and strengthening of surrounding rock; the dual-index joint control method can achieve refined management of the grouting process, avoiding problems such as ineffective grout diffusion or insufficient grouting; the standardized grouting completion judgment criteria can ensure the consistency of reinforcement effect of each grouting section, quickly reduce the water-conducting capacity of abnormal water-conducting areas, and achieve the goals of initial interception and water inrush control.
[0044] According to one embodiment of this application, determining the target modified stratum, which is outside the range of damage caused by mining at the working face and located above the main recharge aquifer, includes: determining the maximum development depth of the floor failure zone caused by mining at the working face by establishing a rock stratum failure mechanics model or using microseismic measurement data; and setting the target modified stratum below the maximum development depth by combining the spatial characteristics of the identified dominant water channel; the target modified stratum is a limestone or sandstone layer with structural bearing capacity and good injectability.
[0045] The maximum development depth of the base plate failure zone is determined by both mechanical model calculation and microseismic measurement. Combined with the spatial distribution of the dominant water channel, the core area for barrier construction is locked. The target modified layer is set below this depth to avoid the impact of mining damage on the modified barrier and ensure the long-term stability of the water-blocking structure. At the same time, the layer must have sufficient bearing capacity and good injectability to ensure the effective diffusion of the modified grout and form a continuous and complete low-permeability water-blocking barrier.
[0046] The target modification layer selection method can accurately locate stable rock strata unaffected by mining, fundamentally avoiding the development of floor fissures that could damage the modified barrier during mining, thus ensuring the long-term effectiveness of the water-blocking structure. The appropriate lithology selection can ensure the uniform diffusion of the modified slurry, forming a continuous and complete low-permeability barrier, significantly increasing the equivalent water-blocking thickness of the floor. At the same time, stable rock strata can provide sufficient structural bearing capacity for the modified barrier, resisting the water pressure of high-confined aquifers and improving the reliability of the water-blocking barrier.
[0047] According to one embodiment of this application, the planar arrangement range and spacing of the horizontal branch segments are determined based on the estimated diffusion radius of the slurry within the target modified layer: the envelope range of the horizontal branch segments covers the entire distribution range of the abnormal water-conducting area and the main water channel, and the planar projection distance between adjacent branch segments is no greater than twice the estimated diffusion radius of the slurry.
[0048] Based on the estimated diffusion radius of the slurry, the layout range and spacing of the branch sections are determined. By designing the envelope range covering the abnormal water-conducting area and the main water channel, it is ensured that all high-risk water-conducting areas are within the protection range of the modified barrier. By controlling the spacing to no more than twice the diffusion radius, the slurry diffusion range of adjacent branch sections can be effectively overlapped, avoiding the appearance of barrier gaps and forming a continuous and complete low-permeability water-blocking barrier.
[0049] The above-mentioned horizontal branch segment layout rules can ensure the continuity and integrity of the modified barrier, effectively avoid the formation of water-blocking blank zones, and cut off the aquifer recharge path from the root. Based on the slurry diffusion radius as the core design basis, the branch segment spacing can be precisely designed, minimizing the amount of directional drilling construction and reducing project costs while ensuring the integrity of the barrier. The envelope design covering abnormal water-conducting areas and main water channels can achieve full protection of high-risk water-conducting paths, greatly improving the water-blocking reliability of the modified barrier.
[0050] According to one embodiment of this application, directional drilling includes: using a drilling sensor to obtain physical response parameters of the rock strata at the bottom of the hole, identifying the lithological boundary between the target modified layer and its adjacent aquitard, and controlling the horizontal branch segment to always extend within the target modified layer by adjusting the tool face angle of the drill string.
[0051] By acquiring the physical response parameters of the rock strata at the bottom of the borehole in real time using drilling sensors, the lithological boundary between the target modified layer and the adjacent aquitard is accurately identified. At the same time, by adjusting the tool face angle of the drill string, the extension trajectory of the directional borehole is corrected in real time to ensure that the horizontal branch segment is always inside the target modified layer, preventing the directional borehole from penetrating the target layer, ensuring the effect of subsequent segmented injection modification, and realizing the continuous construction of the modified barrier.
[0052] According to one embodiment of this application, the subsequent modification range or injection parameters are iteratively adjusted based on monitoring feedback data, including: when the monitored water inflow or the rise in the water level of the replenishment source does not meet expectations, tree-shaped short branch holes are added laterally to the original horizontal branch section to supplement injection into the local weak zones of the modified barrier.
[0053] The iterative adjustment process of the dynamic monitoring system is clearly defined, and reinforcement measures are determined when the modified barrier effect does not meet expectations. By monitoring changes in water inflow and water level of the replenishment source, local weak zones of the modified barrier are accurately identified. Then, by adding tree-shaped short branch holes to the side of the original horizontal branch section, the weak zones are supplemented with injection modification to fill the defects of the modified barrier, improve the integrity and reliability of the water-blocking barrier, and achieve dynamic closed-loop optimization of the treatment plan.
[0054] The dynamic reinforcement mechanism of the modified barrier can specifically address the water-blocking failure problem in local weak zones of the barrier, effectively preventing the overall water-blocking effect of the modified barrier from declining due to local defects. The addition of tree-shaped short branch holes eliminates the need to re-drill the main borehole, enabling rapid supplementary modification of weak areas, significantly shortening the reinforcement construction cycle and reducing project costs. Targeted reinforcement based on monitoring data eliminates the blindness of treatment, ensures the long-term water-blocking effect of the modified barrier, and achieves closed-loop management of water hazard control.
[0055] Finally, it should be noted that the above embodiments are only used to illustrate this application and are not intended to limit this application. Although this application has been described in detail with reference to the embodiments, those skilled in the art should understand that various combinations, modifications, or equivalent substitutions of the technical solutions of this application do not depart from the spirit and scope of the technical solutions of this application and should be covered within the scope of the claims of this application.
Claims
1. A method for in-situ water-retaining grouting modification and optimization of the foundation slab, characterized in that, Includes the following steps: Obtain the basic hydrogeological parameters of the target working face and its underlying aquifers, and delineate the target area for bottom plate water hazard investigation based on the basic parameters. For the target area, a combination of physical detection and verification methods was used to delineate the three-dimensional boundary of the abnormal water-conducting area of the bottom plate; Based on hydrodynamic response characteristic analysis and hydrochemical characteristic identification, the dominant water channel is identified for the three-dimensional boundary of the abnormal water-conducting area. The water source composition and main recharge aquifer of the working face water inflow are determined, as well as the spatial characteristics and water-conducting properties of the dominant water channel. Based on the water source composition and the water-conducting properties of the main water channel, pre-reinforcement grouting materials and injection parameters are matched; according to the matched and determined grouting materials and injection parameters, in-situ pre-reinforcement and initial interception are carried out for the abnormal water-conducting area and the identified main water channel. Based on the spatial location of the main recharge aquifer, the impact range of the bottom plate mining damage caused by the working face, and the spatial characteristics of the main water channel, the target modified layer is determined to be outside the impact range of the mining damage and located above the main recharge aquifer; a well site is arranged on the ground and directional drilling is carried out; Segmented injection modification is carried out along the horizontal branch section of the directional borehole to construct a low-permeability modified barrier within the target modified layer; Establish a dynamic monitoring and evaluation system covering working face water inflow, aquifer water pressure, and modified barrier status, and iteratively adjust the subsequent modification range or injection parameters based on monitoring feedback data.
2. The in-situ water-retaining grouting modification and optimization method for the base plate according to claim 1, characterized in that, The physical detection includes at least one of the following: channel wave seismic exploration, three-dimensional seismic exploration, transient electromagnetic detection, and direct current electrical resistivity tomography.
3. The in-situ water-retaining grouting modification and optimization method for the base plate according to claim 2, characterized in that, The verification probe includes: Verification boreholes are arranged within the abnormal water-conducting area identified by physical exploration. By acquiring the water penetration depth, original water inflow, and water pressure data of the verification boreholes, and combining them with the spatial images from physical exploration, the spatial geometry of the concentrated fracture development zone and karst channels within the abnormal water-conducting area of the base plate is determined.
4. The method for in-situ water-retaining grouting modification and optimization of the base plate according to claim 1, characterized in that, The identification of the dominant water channel, determining the water source composition and main recharge aquifer of the working face water inflow, and the spatial characteristics and water-conducting properties of the dominant water channel, includes: Conduct single-hole or multi-hole pumping tests to obtain the water level rise and fall response characteristics between different aquifers; Background water samples from the aquifer and water samples from the outlet point of the working face are collected. At least one of the following methods is used: water chemical composition comparison, characteristic ion molar ratio analysis, and hydrogen-oxygen isotope relationship analysis to identify the fluid path through which the deep aquifer supplies water to the working face via the abnormal water-conducting area.
5. The method for in-situ water-retaining grouting modification and optimization of the base plate according to claim 1, characterized in that, The in-situ pre-reinforcement and initial flow interception include: The grouting holes are sealed by pressure injection using a multi-stage sealing structure. The multi-stage sealing structure is equipped with at least two-stage casings according to the stratum exposed by the grouting hole and the stability of the surrounding rock. When the grouting hole enters the influence range of a high-pressure aquifer, an additional inlet casing is added to form a three-stage or higher sealing structure.
6. The in-situ water-retaining grouting modification and optimization method for the base plate according to claim 5, characterized in that, The in-situ pre-reinforcement and initial interception use cement-based grout or clay composite grout, and are controlled by a combination of pumping pressure and injection flow rate. At the end of the injection, the injection flow rate is reduced to a set threshold, and the injection pressure is increased to the design final pressure and maintained for a preset time before the reinforcement is considered complete.
7. The method for in-situ water-retaining grouting modification and optimization of the base plate according to claim 1, characterized in that, The determination of the target modified layer located outside the mining-induced damage area of the working face and above the main recharge aquifer includes: By establishing a rock stratum failure mechanics model or using microseismic measurement data, the maximum development depth of the floor failure zone caused by the mining face is determined. Combined with the spatial characteristics of the identified dominant water channels, the target modified stratum is set below the maximum development depth. The target modified stratum is a limestone or sandstone layer with structural bearing capacity and good injectability.
8. The method for in-situ water-retaining grouting modification and optimization of the base plate according to claim 7, characterized in that, The planar layout range and spacing of the horizontal branch segments are determined based on the estimated diffusion radius of the slurry within the target modified layer: the envelope range of the horizontal branch segments covers the entire distribution range of the abnormal water-conducting area and the dominant water channel, and the planar projection distance between adjacent branch segments is no greater than twice the estimated diffusion radius of the slurry.
9. The method for in-situ water-retaining grouting modification and optimization of the base plate according to claim 1, characterized in that, The directional drilling includes: By using drilling sensors to obtain physical response parameters of the rock strata at the bottom of the borehole, the lithological boundary between the target modified layer and its adjacent aquitard is identified, and the horizontal branch segment is controlled to always extend within the target modified layer by adjusting the tool face angle of the drill string.
10. The method for in-situ water-retaining grouting modification and optimization of the base plate according to claim 1, characterized in that, The iterative adjustment of the subsequent modification range or injection parameters based on monitoring feedback data includes: When the monitored water inflow or the rise in the water level of the replenishment source does not meet expectations, tree-shaped short branch holes are added laterally to the original horizontal branch section to supplement the local weak zones of the modified barrier with injection.