Method and system for predicting surface subsidence in a goaf

Abstract

This invention discloses a method and system for predicting surface subsidence in goaf areas, belonging to the field of surface subsidence prediction technology. The method includes the following steps: collecting data on the uneven distribution of residual stress in the goaf area, constructing a three-dimensional seismic wave propagation scenario, and dividing energy-prone areas based on differences in rock density and elasticity; based on the spatial distribution data of these energy-prone areas, deploying graded stress release holes, and using a combination of directional pressure relief and deep grouting to form controllable stress buffer zones at energy-prone sensitive locations, thus establishing a stable residual stress background. This invention, by identifying energy-prone sensitive locations in the goaf in advance and constructing controllable stress buffer zones, transforms surface subsidence analysis from post-event analysis to pre-event perception. Furthermore, by combining dynamic stress and vibration time series to generate subsidence trend maps, it achieves forward identification and risk warning of secondary subsidence.

Description

Technical Field

[0001] This invention relates to the field of surface subsidence prediction technology, specifically to a method and system for predicting surface subsidence in mining subsidence areas. Background Technology

[0002] A goaf refers to an underground cavity or loose area formed after the ore body is extracted during mining operations. These areas, due to the destruction of the original rock mass support, experience movement, deformation, and collapse of the overlying strata, resulting in a loosely structured underground space with redistributed stress. Predicting surface subsidence in goafs involves establishing a correlation between surface deformation and the extent of the goaf based on factors such as the mining depth, thickness, dip angle, geological structure characteristics, and mechanical parameters of the overlying strata. Using physical and mechanical models, numerical simulations, or data-driven methods, the prediction of the amount, extent, and rate of subsidence over time on the surface above the goaf is then made. The purpose of this prediction is to identify potential geological hazards such as surface subsidence, building deformation, and ground fissure expansion in advance, providing a scientific basis for safe production in mining areas and the protection of surface buildings.

[0003] The existing technology has the following shortcomings:

[0004] In the prediction of surface subsidence in mined-out areas, far-field seismic waves, upon entering the residual stress zone, are easily amplified locally due to differences in wave impedance and energy reflection effects, causing stress redistribution in the originally stable equilibrium rock strata. When the frequency of the seismic waves approaches the natural vibration frequency of the residual stress zone, an energy superposition effect occurs, leading to further expansion or even connection of micro-fractures within the rock strata, thereby disrupting the original stress equilibrium structure. This phenomenon easily triggers secondary surface subsidence, resulting in sudden deformation behaviors such as local collapse or slow sinking, giving the surface deformation process delayed and nonlinear characteristics, and posing a significant error risk to traditional subsidence prediction models.

[0005] The information disclosed in the background section is only intended to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to provide a method and system for predicting surface subsidence in goaf areas, so as to solve the problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a method for predicting surface subsidence in goaf areas, comprising the following steps:

[0008] Step 1: Collect the uneven distribution characteristics of residual stress in the goaf, construct a three-dimensional seismic wave propagation scene, divide the energy-accumulating areas according to the difference in rock density and elasticity, determine the potential energy amplification sensitive locations before the seismic vibration, and obtain the spatial distribution data of the energy-accumulating areas.

[0009] Step 2: Based on the spatial distribution data of the energy-accumulating area, graded stress relief holes are set up. A combination of directional pressure relief and deep grouting is used to form a controllable stress buffer zone at the energy-accumulating sensitive location, establish a stable residual stress background, and provide a stable response basis for subsequent vibration detection.

[0010] Step 3: Under the stable state of the stress buffer zone, embed a multi-frequency vibration detection device to dynamically compare the input frequency of the seismic wave with the natural vibration frequency of the rock strata. Based on the comparison results, identify the resonance proximity signal and adjust the decompression rhythm of the stress relief hole to keep the stress state of the buffer zone in harmony with the input frequency of the seismic wave.

[0011] Step 4: Based on the resonance proximity signal obtained by vibration detection comparison, implement seismic wave energy regulation, reduce local energy peaks by means of reverse source intervention and phase misalignment interference, and ensure that the dynamic stress distribution of the overlying strata and the stress buffer response remain synchronized.

[0012] Step 5: Combine the stress change information during the energy regulation phase to conduct surface subsidence response monitoring, perform corresponding analysis between the dynamic stress sequence and the seismic wave vibration time series, generate an updated surface subsidence trend map, identify the secondary subsidence triggering area, and output the early warning result of the forward movement of surface subsidence risk.

[0013] Preferably, the steps of collecting the uneven distribution characteristics of residual stress in the goaf, constructing a three-dimensional seismic wave propagation scenario, delineating energy-accumulating areas, and determining potential energy amplification sensitive locations include:

[0014] A comprehensive survey of the geological structure and residual stress state of the goaf and its surrounding areas was conducted. Multiple stress measuring points were arranged in the overlying strata, lateral surrounding rock and bottom rock mass. Stress parameters at different depths and directions were collected using borehole stress gauges, acoustic emission probes and core cleavage analysis methods to form a spatial distribution map of residual stress.

[0015] Based on the spatial distribution data of residual stress, a three-dimensional seismic wave propagation scenario is constructed. The three-dimensional structure of the goaf and overlying rock strata is reconstructed in the spatial coordinate system. The residual stress data is mapped into the model, the seismic wave propagation path is set, and wave reflection boundaries and energy dissipation areas are established.

[0016] Based on the differences in rock density and elasticity in the three-dimensional seismic wave propagation scenario, energy-accumulating regions are divided, and the wave impedance abrupt interface is spatially partitioned and assigned energy response coefficients and connectivity properties.

[0017] Based on the energy transfer path of the energy-accumulating region, potential energy amplification sensitive locations are determined, forming spatial distribution data of the energy-accumulating region that includes energy response intensity and residual stress state.

[0018] Preferably, the steps of deploying graded stress relief holes, implementing directional pressure relief and deep grouting, and establishing a stable residual stress background based on the spatial distribution data of energy-prone areas include:

[0019] Based on the spatial distribution data of energy-accumulating areas, the hole layout design is carried out in the stress-sensitive areas inside the goaf and the overlying strata. According to the energy response intensity, the energy-accumulating areas are divided into main control areas, secondary control areas and auxiliary areas. The spatial range, hole spacing, hole depth and hole diameter of the stress relief holes are determined to form a multi-layer stress diversion network covering the energy-accumulating areas.

[0020] Targeted decompression operations are implemented. In the primary stress relief holes, controllable microcrack zones are formed by deep drilling blasting, mechanical enlargement, or hydraulic fracturing. In the secondary and tertiary stress relief holes, local energy is released by water pressure pulses or mechanical vibration to construct a spatial decompression gradient zone.

[0021] Deep grouting is carried out using graded stress relief holes as channels. Inorganic grout is injected under pressure or at medium and low pressure at different hole positions to form a continuous reinforcement zone covering key nodes in areas prone to energy accumulation, and a controllable stress buffer zone is formed at energy-sensitive locations.

[0022] By combining spatial distribution data of energy-prone areas, stress buffer zones are adjusted to achieve stress equilibrium. A stable residual stress background is established through micro-secondary grouting, ventilation and pumping, and surface backfilling.

[0023] Preferably, the steps of embedding a multi-frequency vibration detection device in the stable state of the stress buffer zone, performing frequency comparison, identifying resonance proximity signals, and adjusting the stress relief orifice pressure relief rhythm include:

[0024] Once the stress buffer zone is in a stable state, based on the hierarchical distribution of stress relief holes and the spatial morphology of energy-accumulating areas, the multi-frequency vibration detection device is embedded in the rock structure in sections. Main control detection points are set up around the primary stress relief holes, and secondary and auxiliary detection points are set up in the areas of secondary and tertiary stress relief holes, forming a monitoring network that decreases from the center outward.

[0025] Dynamic comparison of seismic wave input frequency and natural vibration frequency of rock strata is carried out. Based on the frequency signals collected by the multi-frequency vibration detection device, the vibration amplitude, period changes and waveform characteristics of different monitoring points are correlated in time to identify resonance proximity signals and determine the spatial distribution range.

[0026] Based on the comparison results, the stress relief hole pressure release rhythm is adjusted. Taking the first-level stress relief hole as the control center, the residual stress release speed is adjusted by controlling the pressure release interval and sequence, so that the stress buffer zone maintains a coordinated response.

[0027] After the pressure relief rhythm is adjusted, the overall stress state of the stress buffer zone is coordinated, and the gas pressure, hydraulic transmission rate and grouting diffusion direction of the stress relief hole are controlled to form a stress distribution gradient that decreases from the inside to the outside and maintain dynamic balance.

[0028] Preferably, when coordinating the overall stress state of the stress buffer zone, the first-level stress relief hole is controlled to use an intermittent pressure relief method, the second-level stress relief hole is controlled to use a low-speed pressure relief method, and the third-level stress relief hole is controlled to perform periodic small-amplitude stress relief, so as to maintain the continuous distribution of the stress field in the buffer zone and form a stable energy absorption zone.

[0029] Preferably, the steps for implementing seismic wave energy modulation based on the resonance proximity signal obtained from vibration detection comparison include:

[0030] After obtaining the resonance proximity signal from vibration detection comparison, the target area for seismic wave energy modulation is determined based on the spatial range of the stress buffer zone. The time window and spatial location of the resonance proximity signal are extracted, and the spatial mapping relationship between the seismic wave propagation direction and the energy gradient is established.

[0031] Based on the determination of the target area, reverse source intervention is implemented. Reverse source points are set up below the rock strata corresponding to the resonance area to control the energy release intensity, initiation time and wave direction of the source. The peak energy of the seismic wave is reduced and the energy distribution is balanced by reverse wave interference.

[0032] Implement phase misalignment interference by setting up phase misalignment interference sources along the energy propagation path. By adjusting the phase of the interference wave to form a half-period difference with the main seismic wave, the peak energy of the main wave is weakened and the energy density is evenly distributed.

[0033] Based on the completion of reverse source intervention and phase misalignment interference, the dynamic stress distribution and stress buffer response of the overlying strata are coordinated. By adjusting the release interval of the reverse source and the phase difference of the interference wave, the stress system is kept in dynamic equilibrium and energy attenuation and transfer are achieved.

[0034] Preferably, in the coordinated implementation of reverse seismic source intervention and phase misalignment interference, the reverse seismic source is located in the energy propagation reflection zone below the stress buffer zone, and the interference source is located in the intersection area of ​​the energy reflection zones outside the stress buffer zone. The two are activated sequentially in time. The release interval of the reverse seismic source and the phase difference of the interference wave are dynamically adjusted according to the change of the peak energy of the seismic wave, so as to keep the stress response of the overlying rock layer and the stress release process of the stress buffer zone synchronized.

[0035] Preferably, the steps for conducting surface subsidence response monitoring and outputting early warning results for the forward movement of surface subsidence risk, in conjunction with stress change information during the energy regulation phase, include:

[0036] After the energy regulation phase is completed, stress change information generated during the seismic wave energy regulation process is collected. Through multiple stress sensing devices deployed inside the stress buffer zone, at the rock interface and on the surface, the stress change amplitude, direction and rate are recorded to form a dynamic stress sequence with time order.

[0037] Surface settlement response monitoring is carried out based on dynamic stress sequence. A multi-layer displacement monitoring array is set up above the goaf to collect the changes in vertical and horizontal displacement of the surface in real time, and the surface deformation is analyzed in correspondence with the stress sequence of the stress buffer zone.

[0038] By analyzing the correlation between dynamic stress sequences and seismic wave vibration time series, and by superimposing surface displacement monitoring data and stress change information to form a three-dimensional correlation between time, stress and settlement, a surface settlement trend update map is generated.

[0039] Based on the updated surface subsidence trend map, secondary subsidence triggering areas are identified. By combining the residual stress distribution of the stress buffer zone with the changes in surface subsidence rate, an early warning index for the forward movement of surface subsidence risk is established, and the early warning results for the forward movement of surface subsidence risk are output.

[0040] Preferably, in the process of generating the surface subsidence trend update map, based on the synchronous relationship between the seismic wave vibration sequence and the stress release rate of the stress buffer zone, the surface displacement increment is analyzed by time series, and the subsidence velocity change is represented by color gradient in the map. By identifying high displacement gradient zones, the secondary subsidence triggering area is determined, thereby realizing the dynamic update of the surface subsidence trend and the identification of risk shift.

[0041] The prediction system for surface subsidence in goaf areas includes an energy distribution identification module, a stress buffer construction module, a vibration frequency comparison module, a seismic energy regulation module, and a subsidence monitoring and early warning module.

[0042] The energy distribution identification module collects the uneven characteristics of residual stress distribution in the goaf, constructs a three-dimensional seismic wave propagation scene, and divides the energy-accumulating areas based on the difference in rock density and elasticity.

[0043] The stress buffer construction module, based on the spatial distribution data of energy-prone areas, lays out graded stress relief holes and adopts a combination of directional pressure relief and deep grouting to form a controllable stress buffer zone at energy-prone sensitive locations and establish a stable residual stress background.

[0044] The vibration frequency comparison module, under the stable state of the stress buffer zone, embeds a multi-frequency vibration detection device to dynamically compare the input frequency of the seismic wave with the natural vibration frequency of the rock strata. Based on the comparison results, it identifies the resonance proximity signal and adjusts the decompression rhythm of the stress relief hole.

[0045] The seismic energy regulation module implements seismic wave energy regulation based on the resonance proximity signal obtained by vibration detection comparison, and reduces local energy peaks through reverse source intervention and phase misalignment interference.

[0046] The settlement monitoring and early warning module combines stress change information during the energy regulation phase to conduct surface settlement response monitoring, analyzes the correlation between dynamic stress sequences and seismic wave vibration time series, generates updated surface settlement trend maps, identifies secondary settlement triggering areas, and outputs early warning results for the forward movement of surface settlement risks.

[0047] The technical effects and advantages provided by the present invention in the above technical solution are as follows:

[0048] This invention, through meticulous acquisition of the uneven distribution characteristics of residual stress in goaf areas and the construction of a three-dimensional seismic wave propagation scenario, identifies potential energy amplification sensitive locations before seismic vibration occurs, transforming surface subsidence prediction from post-event analysis to pre-event perception and process tracking. Based on this, by forming a controllable stress buffer zone and introducing dynamic vibration detection and energy regulation methods, the rock strata remain in a coordinated stress response state throughout the seismic wave input process, effectively suppressing the cumulative amplification of energy in local areas. This fundamentally reduces the probability of secondary subsidence caused by stress redistribution, thereby improving the overall reliability and stability of surface subsidence prediction in goaf areas.

[0049] This invention systematically correlates stress changes during seismic wave vibration timing and energy regulation stages with surface subsidence response. By generating continuously updated surface subsidence trend maps, the surface deformation process can be continuously expressed and identified in advance. This method can accurately reflect the delayed and phased evolution characteristics of subsidence, determine risk areas before subsidence develops into a significant hazard, and output forward-looking early warning results. This provides a clear basis for the protection and safety decisions of surface facilities in mining areas, enabling surface subsidence prediction to not only have quantitative analysis capabilities but also dynamic early warning and risk indication value. Attached Figure Description

[0050] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0051] Figure 1This is a flowchart of the method for predicting surface subsidence in goaf areas according to the present invention.

[0052] Figure 2 This is a schematic diagram of the module of the prediction system for surface subsidence in the goaf area according to the present invention. Detailed Implementation

[0053] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, they are provided so that the description of this disclosure will be more complete and fully convey the concept of the exemplary embodiments to those skilled in the art.

[0054] This invention provides, for example Figure 1 The method for predicting surface subsidence in goaf areas, as shown, includes the following steps:

[0055] Step 1: Collect the uneven distribution characteristics of residual stress in the goaf, construct a three-dimensional seismic wave propagation scene, divide the energy-accumulating areas according to the difference in rock density and elasticity, determine the potential energy amplification sensitive locations before the seismic vibration, and obtain the spatial distribution data of the energy-accumulating areas.

[0056] The specific implementation method for this step is as follows:

[0057] A comprehensive survey of the geological structure and residual stress state of the goaf and its surrounding areas was conducted. During the process, after the ore body mining was completed, multiple stress measurement points were deployed in the overlying strata, lateral surrounding rock, and floor rock mass of the goaf. The measurement points were distributed according to a spatial grid, with multiple profiles arranged vertically and profile lines set horizontally according to the dip angle of the ore body to form a three-dimensional measurement network. Using borehole stress gauges, acoustic emission probes, and core cleavage analysis, the magnitude, direction, pore pressure, and lithological parameters of the internal stress within the rock strata at different depths and orientations were measured in-situ. All data were primarily based on in-situ sampling results. By zoning the stress in the surrounding rock stress relief zone, collapse zone, and residual coal pillar area, a complete spatial distribution map of residual stress was formed. The collected data was spatially interpolated to form a three-dimensional data grid. Each unit point in the data grid contains multiple parameters such as principal stress magnitude, direction, lithology, density, and porosity, accurately reflecting the uneven distribution characteristics of stress within the goaf. After data collection is completed, the spatial morphology, stratum thickness, fracture structure and joint location of the goaf are incorporated into the residual stress database by combining geological structure map, stratigraphic comparison map and mining records, forming a basic dataset that can be used for subsequent 3D scene construction.

[0058] After acquiring the spatial distribution data of residual stress, a three-dimensional seismic wave propagation scenario was constructed. This process, based on geological profile data, rock density, elastic parameters, and residual stress data, reconstructs a geological model of the goaf and its overlying strata in a three-dimensional spatial coordinate system. The model is built upon measured geological data, constructing a three-dimensional structure including the roof, goaf, floor, and adjacent strata through layer-by-layer stacking. Each unit cell in the model corresponds to a set of lithological parameters, including rock type, density, elastic modulus, Poisson's ratio, and water-bearing characteristics. By mapping residual stress data to the three-dimensional structure, the stress distribution spatially corresponds to the geological structure morphology. Based on this, the seismic wave propagation path is introduced into the model, setting propagation trajectories of seismic waves incident from different directions to simulate the propagation and energy transfer laws of waves at different medium interfaces. The three-dimensional seismic wave propagation scenario includes the wave reflection boundary of the overlying strata, the abrupt change surface of wave impedance in the goaf cavity, and the energy dissipation region of the fracture development zone, enabling the model to reflect the wave propagation direction, propagation speed, and energy change process. The construction of this scenario provides a realistic spatial basis for energy response analysis and lays the foundation for the subsequent identification of energy-concentrating regions.

[0059] Subsequently, energy-accumulating regions were delineated based on the differences in rock density and elasticity in the 3D seismic wave propagation scenario. To implement this process, density and elasticity parameters of each unit cell in the 3D scenario were first extracted and spatially superimposed with residual stress distribution data. Density reflects the compactness and porosity of the rock strata, while elasticity reflects the strain response of the rock mass under external forces. The difference between the two represents the energy reflection and absorption capacity of the medium under seismic wave action. In 3D space, these parameters were compared and zoned layer by layer to identify spatial interfaces where wave impedance abruptly changes. These interfaces are typically distributed at the boundaries of different lithological layers, the contact between goaf and overlying strata, fault fracture zones, and the boundaries of aquifers. After identifying the zones of abrupt changes in density and elasticity, these areas were defined as the main spatial locations for energy accumulation. Simultaneously, considering the uneven distribution of residual stress, the locations where energy is reflected or concentrated along the propagation path were determined. Spatial cluster analysis was performed on these locations to delineate the 3D range of energy-accumulating regions, and each region was assigned an energy response coefficient, spatial coordinates, and connectivity attributes with adjacent regions. The resulting energy-accumulating region can serve as the basis for screening sensitive locations for energy amplification in subsequent steps.

[0060] After delineating energy-prone areas, the potential energy amplification-sensitive locations are identified based on the energy transfer paths of the 3D seismic wave propagation scenario, and spatial distribution data of these energy-prone areas are generated. During implementation, the energy response values ​​and residual stress distribution characteristics within these areas are jointly analyzed to identify locations with abrupt stress gradient changes and high wave energy reflectivity. Local energy superposition calculations are performed on each energy-prone area, and by identifying interference zones in the wave energy in space, points where local energy enhancement may occur are determined. These points are typically located at the boundary between the overlying strata and the goaf, in areas of rapid changes in stratum density, at the ends of fault extensions, and at the boundaries of collapse zones. After identifying the potential energy amplification-sensitive locations, the 3D coordinates, energy concentration levels, and residual stress states of these locations are integrated to form a spatial distribution dataset. This dataset, using energy response intensity as the primary parameter and 3D geographical location as the index, reflects the energy distribution patterns of the goaf and surrounding strata before seismic wave action. This dataset allows for the creation of spatial maps of energy-sensitive locations within goaf areas, clarifying the spatial relationships between energy-accumulating regions. This provides spatial guidance for the subsequent layout of stress relief holes and the construction of stress buffer zones, enabling subsequent steps to conduct seismic energy regulation and surface subsidence prediction based on accurate energy distribution.

[0061] This step, through the spatialization of multidimensional parameters of the goaf and its overlying strata, organically combines residual stress characteristics, stratum density, elasticity difference, and seismic energy propagation laws to form a geological spatial model that can reflect energy response characteristics, laying the data and structural foundation for the dynamic prediction of surface subsidence in the goaf.

[0062] Step 2: Based on the spatial distribution data of the energy-accumulating area, graded stress relief holes are set up. A combination of directional pressure relief and deep grouting is used to form a controllable stress buffer zone at the energy-accumulating sensitive location, establish a stable residual stress background, and provide a stable response basis for subsequent vibration detection.

[0063] The specific implementation method for this step is as follows:

[0064] Based on the spatial distribution data of energy-accumulating areas obtained in the previous stage, borehole layout design was carried out in the stress-sensitive areas within the goaf and overlying strata. This process primarily targets energy-amplifying sensitive locations within the energy-accumulating areas, determining the layout range and spacing of stress relief boreholes through spatial coordinate positioning. The borehole layout design follows a hierarchical principle, dividing the energy-accumulating areas into primary control zones, secondary control zones, and auxiliary zones according to energy response intensity. The primary control zone selects the spatial location with the highest energy accumulation and the most concentrated stress gradient abrupt change as the primary stress relief borehole layout area; the secondary control zone corresponds to key nodes in the energy transmission path, where secondary stress relief boreholes are laid out; the auxiliary zone is located at the end of energy transmission and stress buffer boundaries, where tertiary stress relief boreholes are laid out. During the borehole layout process, the borehole depth and diameter are determined based on the stratum thickness, dip angle, and geological structural characteristics, ensuring that each stress relief borehole penetrates the stress concentration zone of the energy-accumulating area. Through this hierarchical layout method, a multi-layered stress diversion network covering the energy-accumulating areas can be formed in three-dimensional space, rationally diverting the energy transmission path within the goaf and providing a structural foundation for subsequent pressure relief and grouting processes.

[0065] After the graded stress relief boreholes are laid out, directional stress relief operations are implemented to reduce localized stress concentrations at energy-sensitive locations. The directional stress relief is guided by the spatial distribution of energy-sensitive areas. In the primary stress relief boreholes, deep drilling and blasting, mechanical enlargement, and hydraulic fracturing are used to create controllable micro-fracture zones along the energy accumulation direction. These fracture zones connect with the original joints and fissures in the rock strata, forming stress relief channels that gradually transmit high-value stresses concentrated within the energy-sensitive areas outwards, reducing the degree of localized energy accumulation. Secondary and tertiary stress relief boreholes use low-intensity hydraulic pulses or mechanical vibration to slowly release energy along the depth direction, preventing excessive stress relief from causing rock structure instability. The orientation of the directional stress relief is consistent with the energy amplification sensitive locations identified in the previous stage, ensuring that the stress release direction is opposite to the energy accumulation direction, thus creating an energy dissipation zone in space. Through a combination of graded and directional stress relief methods, a distinct stress relief gradient zone can be formed within the goaf area, laying the foundation for stress equilibrium in the construction of stress buffer zones.

[0066] After completing the directional decompression operation, deep grouting is implemented at energy-sensitive locations to further stabilize the local rock mass structure and construct a controllable stress buffer zone. Deep grouting is carried out using staged stress relief holes as channels. High-viscosity, low-shrinkage inorganic grout is selected and injected under pressure in the first-stage holes to fill the fracture channels and voids formed after decompression. The grouting pressure and rate are controlled in zones according to the rock layer density and decompression effect, allowing the grout to spread uniformly along the fracture direction and gradually solidify. Second- and third-stage holes use medium- and low-pressure grouting methods, injecting fine-grained grout with strong self-flowing properties to seal micro-fractures and seepage channels, preventing stress re-concentration. During the grouting process, by adjusting the grouting sequence and intervals, the grout forms a continuous reinforcement zone in space. This reinforcement zone covers key nodes and sensitive boundaries in the energy-sensitive area, effectively filling the pores in the decompressed rock mass and forming a consolidated structure with a certain degree of ductility. After grouting is completed, the solidified grout forms a composite stress layer with the surrounding rock mass. This composite layer can absorb and disperse local energy impacts under external forces, thereby forming a stable stress buffer zone at energy-sensitive locations, providing a balanced stress background for subsequent seismic wave vibration detection.

[0067] After forming a controllable stress buffer zone, the residual stress state of the entire stress buffer zone is balanced and adjusted based on the spatial distribution data of the energy-accumulating area to establish a stable residual stress background. This process involves micro-grouting near the primary stress relief boreholes to compensate for minor cracks generated during pressure relief; simultaneously, low-pressure ventilation and pumping are used in the secondary stress relief borehole area to eliminate localized water pressure increases caused by grouting, thereby restoring stress equilibrium within the rock mass. Based on this, surface backfilling is performed on the tertiary boreholes at the boundary of the energy-accumulating area, forming a homogeneous stress overburden layer in the rock strata above the stress buffer zone. Through this process, the residual stress distribution within the energy-accumulating area changes from a concentrated state to a relatively flat spatial state, reducing the stress gradient within the buffer zone and achieving overall structural stability. This stable residual stress background maintains a uniform response when seismic waves are introduced, preventing abrupt changes in the energy transfer path and avoiding the risk of localized collapse due to energy amplification effects.

[0068] Through the implementation of the above steps, starting from the spatial distribution data of energy-prone areas, and through the precise layout of graded stress relief holes, the layer-by-layer implementation of directional pressure relief, the structural reinforcement of deep grouting, and the stabilization treatment of stress buffer zones, the orderly diversion and redistribution of stress within the goaf was achieved. This process, through physical control methods, formed a continuous and controllable stress buffer zone at energy-prone sensitive locations, creating a stable residual stress background within the goaf and ensuring that seismic waves can accurately reflect the dynamic characteristics of the rock strata during propagation.

[0069] Step 3: Under the stable state of the stress buffer zone, embed a multi-frequency vibration detection device to dynamically compare the input frequency of the seismic wave with the natural vibration frequency of the rock strata. Based on the comparison results, identify the resonance proximity signal and adjust the decompression rhythm of the stress relief hole to keep the stress state of the buffer zone in harmony with the input frequency of the seismic wave.

[0070] The specific implementation method for this step is as follows:

[0071] After the stress buffer zone reaches a stable state, multi-frequency vibration detection devices are embedded into the rock structure according to a zoned deployment principle. The deployment process uses the previously formed stress buffer zone as a spatial basis. Based on the hierarchical distribution of stress relief holes and the spatial morphology of energy-accumulating areas, high-sensitivity vibration detection points are set in the main control area around the primary stress relief holes. Secondary and auxiliary detection points are set in the areas of secondary and tertiary stress relief holes, forming a monitoring network that decreases in intensity layer by layer from the center outwards. Each detection point is installed at a fixed position inside the rock stratum and is tightly integrated with the rock mass through an anti-interference anchoring structure to ensure synchronization of the detection device's dynamic response with the rock stratum. The multi-frequency vibration detection device has a wide-band vibration sensing capability, capable of sensing the amplitude changes of seismic wave input frequencies in different bands and the response vibration characteristics of the stress buffer zone rock strata. After deployment, all detection devices are connected to the surface monitoring terminal via data transmission lines to ensure real-time acquisition of seismic wave input frequencies under stable stress buffer conditions, providing a continuous frequency signal data source for subsequent comparisons.

[0072] After the detection device is embedded, a dynamic comparison is performed between the input frequency of seismic waves and the natural vibration frequency of the rock strata. This process is based on the frequency signals collected by the multi-frequency vibration detection device. By simultaneously recording the input frequency of external seismic waves and the response frequency inside the stress buffer layer, a dynamic correspondence between the two types of signals is achieved. During the comparison, the natural vibration frequencies of the rock strata at different depths and directions are identified by temporally correlating the vibration amplitude, period changes, and waveform characteristics at each monitoring point. The comparison results can reflect the dynamic relationship between the seismic wave propagation path in the stress buffer and the structural characteristics of the rock strata themselves. When the input frequency of seismic waves is close to the natural vibration frequency of the rock strata, the detection device captures signal characteristics of amplitude amplification and waveform overlap, indicating a potential trend of energy resonance in a local area. By comparing the frequency differences between the detection points in the main control area and the secondary control area, the spatial distribution range of the resonance proximity area can be identified, providing a location basis for subsequent adjustments to the decompression rhythm.

[0073] After identifying the resonance approach signal, the decompression rhythm of the stress relief orifices is adjusted based on the comparison results. The adjustment process uses the primary stress relief orifice as the control center and the secondary and tertiary stress relief orifices as auxiliary channels, forming a multi-point synchronous adjustment within the stress buffer zone. By controlling the interval and sequence of decompression operations, the decompression direction is kept consistent with the direction of seismic wave energy propagation, and the decompression time distribution of each stress relief orifice is adjusted according to the strength of the resonance approach signal. When the frequency variation range of the resonance approach signal is narrow, micro-decompression operations are preferentially implemented in the main control area to match the residual stress release rate within the stress buffer zone with the seismic wave input period, thereby preventing stress accumulation within the buffer zone. When the comparison results show that the resonance signal persists, the decompression interval in the secondary control area is extended to form a stress relief layer, allowing the seismic wave energy to be gradually dispersed during propagation. This adjustment process, while maintaining the overall stability of the stress buffer zone, utilizes the rhythmic differences in graded decompression to achieve synchronous coordination of energy response, thereby avoiding the local stress amplification effect caused by the overlap of the seismic wave input frequency and the natural frequency of the rock strata.

[0074] After the stress relief hole depressurization rhythm is adjusted, the overall stress state of the stress buffer zone is coordinated to maintain a dynamic balance with the seismic wave input frequency. The coordination process is based on the adjusted depressurization rhythm, maintaining a continuous stress field distribution within the buffer zone by controlling the gas pressure, hydraulic transmission rate, and grout diffusion direction of the stress relief holes. For depressurization holes located in the main control area, an intermittent depressurization method is adopted to ensure that the stress waves generated by depressurization are out of phase with the external seismic waves; for depressurization holes in the secondary control area, a low-speed depressurization method is used to gradually dissipate residual stress; for depressurization holes in the auxiliary area, periodic small-amplitude stress release is performed to maintain the equilibrium state of the rock strata surrounding the stress buffer zone. Through the coordinated control of stress relief holes at different levels, the stress state within the buffer zone is coordinated with the seismic wave input frequency in time, forming a stress distribution gradient that gradually decreases from the inside to the outside in space. The stress buffer zone in this state can form a stable energy absorption zone during the propagation of seismic waves, so that the energy of seismic waves gradually attenuates when entering the buffer zone, thereby ensuring the integrity and stability of the rock structure under dynamic vibration, and providing an accurate stress response basis for subsequent seismic wave energy regulation and surface subsidence prediction.

[0075] Through the above steps, real-time matching between seismic wave propagation and stress release is achieved under the stable state of the stress buffer zone, enabling the buffer zone to maintain a balanced mechanical response as external vibration conditions change. This avoids the energy superposition effect caused by the seismic wave and the natural frequency of the rock strata being close, thereby ensuring the structural safety of the goaf under seismic disturbance.

[0076] Step 4: Based on the resonance proximity signal obtained by vibration detection comparison, implement seismic wave energy regulation, reduce local energy peaks by means of reverse source intervention and phase misalignment interference, and ensure that the dynamic stress distribution of the overlying strata and the stress buffer response remain synchronized.

[0077] The specific implementation method for this step is as follows:

[0078] After obtaining the resonance proximity signal from vibration detection and comparison, the target area for seismic wave energy modulation is determined. This process centers on the stress buffer zone, using the resonance proximity area identified in the previous stage as the key area for energy modulation. By comparing the spatial correspondence between the seismic wave input frequency and the natural vibration frequency of the rock strata, the temporal window and spatial location of the resonance proximity signal are extracted. Spatially, the area with concentrated frequency changes in the resonance proximity signal, bounded by the interior and edges of the stress buffer zone, is identified as the main intervention area; temporally, the periodic interval of the signal energy peak is determined as the intervention period. Based on this identification result, a spatial mapping relationship between the seismic wave propagation direction and the energy gradient is established, clarifying the location of high-energy-density areas in the seismic wave energy transmission path. This step provides precise target location for subsequent deployment of reverse seismic sources and phase misalignment interference, enabling the seismic wave energy modulation process to be spatially targeted and temporally controllable.

[0079] After identifying the target area, reverse seismic source intervention is implemented to counteract the peak energy accumulation of seismic waves in local areas. The setup of the reverse seismic source intervention is based on the structural characteristics of the goaf and overlying strata, with reverse seismic source points positioned below the strata corresponding to the resonance area. The locations of the reverse seismic source points are chosen in the reflection zone of the energy propagation path in the rock mass below the stress buffer zone to ensure that the wave energy generated by the reverse source propagates in the opposite direction to the main shock wave. During implementation, precise control of the energy release intensity, initiation time, and wave direction of the seismic source ensures that the energy waves emitted by the reverse source meet and interfere with the original seismic wave in space. When the two energy waves overlap in the propagation medium, the stress wave generated by the reverse source has an out-of-phase phase with the main wave peak of the original shock wave, thus reducing the local energy peak after spatial superposition. Through continuous reverse seismic source intervention, the peak response of the seismic wave in the energy-accumulating area is gradually weakened, the energy distribution curve tends to flatten, and stress reconcentration caused by energy accumulation is avoided. This process achieves directional energy cancellation through physical wave interference without damaging the stress buffer structure, providing an effective technical means to maintain the stability of the dynamic stress distribution of rock strata.

[0080] After the reverse source intervention is completed, phase-shift interference is further implemented to reduce the superposition effect of residual energy waves. This process is based on the comparison between the input frequency of the seismic wave and the stress response frequency within the stress buffer zone. By setting up phase-shift interference sources along the energy propagation path, the propagation phase of the energy wave is changed, causing a phase difference between it and the original wave when it reaches the energy-sensitive location. The phase-shift interference is set up in the intersection area of ​​the stress buffer zone and the energy reflection zone, forming an intervention pattern that complements the reverse source. During propagation, the phase of the energy wave generated by the interference source is adjusted to differ from the main seismic wave by half a period, thereby weakening the energy peak of the main wave during spatial superposition. When the original seismic wave propagates in the rock strata to the energy-sensitive area, the peaks and valleys of the interference wave and the main wave alternately superimpose, causing the energy density to be redistributed spatially, the energy peak to be weakened, and the energy distribution to be more uniform. Through the continuous effect of phase-shift interference, the propagation trajectory of the seismic wave in the goaf no longer exhibits concentrated superposition, and local stress concentration is further reduced. Phase misalignment interference and reverse source intervention create a dual energy regulation effect, complementing each other spatially and connecting with each other temporally, making the energy reduction process more stable and controllable.

[0081] After the reverse source intervention and phase misalignment interference are completed, the dynamic stress distribution of the overlying strata and the response of the stress buffer zone are coordinated to ensure synchronization. The coordination process is based on the energy-controlled stress field distribution, with continuous monitoring and dynamic adjustment of the stress gradient inside and outside the stress buffer zone. By adjusting the release interval of the reverse source and the phase difference of the interference wave, the stress response generated in the overlying strata during seismic wave propagation is matched with the stress release process within the buffer zone. When seismic wave energy propagates in the strata, the buffer zone can absorb and transmit it with the same vibration frequency and similar phase response, thus ensuring continuous attenuation of the seismic wave energy along the propagation path. Through this process, the dynamic stress distribution of the overlying strata and the response of the stress buffer zone are consistent in time and space, avoiding stress lag or lead, and preventing deformation and instability of the strata structure due to uncoordinated energy transfer. After coordination, the entire stress system maintains a dynamic equilibrium, the energy of the seismic wave during propagation is effectively dispersed and attenuated, and the trend of surface subsidence is controlled.

[0082] Through the implementation of the above steps, a complete seismic wave energy regulation process is formed, from target area identification based on resonance proximity signals, reverse source intervention, phase misalignment interference to the synchronous coordination of dynamic stress distribution in the overlying strata and buffer zone response. This process, through active intervention in the seismic wave energy propagation path and spatial phase, reduces local energy peaks, making energy transfer within the goaf more uniform and stable, and effectively prevents the resonance superposition effect between seismic waves and the natural frequencies of the rock strata, ensuring the coordination between the energy response of the stress buffer zone and the stress distribution in the overlying strata.

[0083] Step 5: Combine the stress change information during the energy regulation phase to conduct surface subsidence response monitoring, perform corresponding analysis between the dynamic stress sequence and the seismic wave vibration time series, generate a surface subsidence trend update map, identify the secondary subsidence triggering area, and output the early warning result of the forward movement of surface subsidence risk.

[0084] The specific implementation method for this step is as follows:

[0085] After the energy regulation phase, stress change information generated during the seismic wave energy regulation process is collected to establish a basic data framework for monitoring surface subsidence response. This step focuses on the stress distribution state of the stress buffer zone and overlying strata. Multiple stress sensing devices deployed within the buffer zone, at strata interfaces, and on the surface continuously record the amplitude, direction, and rate of stress changes at different times during the seismic wave energy regulation period. Each monitoring point corresponds to a specific intervention action during the energy regulation phase, such as the time point of reverse source release or phase misalignment interference. Continuous acquisition of this data forms a dynamic stress sequence with a temporal order. This sequence not only reflects the impact of energy regulation on local stress distribution but also records the rebalancing process of the strata after energy reduction. Simultaneously, by combining the spatial coordinates of the seismic wave propagation direction and the stress buffer zone response, the collected stress change information is converted into a three-dimensional spatial dataset, providing a dynamic basis for subsequent surface subsidence response monitoring and enabling the monitoring process to comprehensively reflect the spatiotemporal relationship between stress transmission and surface displacement.

[0086] After collecting stress change information, surface subsidence response monitoring is implemented to establish a real-time correspondence between surface deformation and the dynamic stress sequence of the stress buffer zone. This step involves deploying a multi-layer displacement monitoring array on the surface above the goaf, with monitoring points evenly distributed along the surface subsidence influence range and spatially corresponding to the monitoring points in the stress buffer zone. Each surface monitoring point records vertical and horizontal displacement changes using a high-precision displacement sensing device, and simultaneously collects surface vibration acceleration and velocity parameters. In this way, surface subsidence monitoring not only captures the overall subsidence trend but also reflects localized uneven subsidence behavior. When stress redistributes within the stress buffer zone, the surface monitoring array can promptly reflect the corresponding deformation response. During monitoring, all surface displacement data are time-aligned with the dynamic stress sequence formed during the energy regulation phase, ensuring that each stress change event corresponds to a surface displacement response cycle. This continuous monitoring method establishes a direct link between surface subsidence response and the energy regulation process, enabling surface deformation analysis to move beyond static observation and form a dynamic response system, thereby accurately revealing the transmission impact of energy changes on surface deformation.

[0087] Based on surface subsidence response monitoring, dynamic stress sequences are correlated with seismic wave vibration time series to generate updated surface subsidence trend maps. This process uses seismic wave vibration time series as the timeline, overlaying surface displacement monitoring data with stress change information to form a three-dimensional correlation between time, stress, and subsidence. By comparing the changes in seismic wave input frequency, stress release rate in stress buffer zones, and surface displacement increments at different time periods, the synchronous relationship between seismic wave energy input and surface subsidence rate is identified. During the analysis, the focus is on delayed subsidence areas that appear after the energy regulation phase, i.e., areas where displacement continues to increase even after seismic wave energy reduction. These areas are typically located at the edges of stress buffer zones, lithological abrupt change zones, or areas with well-developed surface fractures. By comparing the time series of these areas with the energy change sequences, the correspondence between inflection points of surface subsidence rate changes and seismic wave time series is extracted. Spatially, the analysis results are mapped onto a surface model above the goaf to generate updated surface subsidence trend maps. This map uses color gradients or spatial elevation to express the changing trends of subsidence velocity and cumulative displacement, which can intuitively reflect the dynamic evolution characteristics of surface subsidence and provide data support for identifying potential secondary subsidence triggering areas.

[0088] After the surface subsidence trend update map is generated, the system identifies secondary subsidence triggering areas based on the correlation between stress change patterns and surface deformation characteristics, and outputs early warning results for the forward movement of surface subsidence risk. The identification process primarily focuses on high displacement gradient zones in the surface subsidence trend map, combined with the residual stress distribution within stress buffer zones, to spatially locate areas with significant changes in surface subsidence rate. These areas typically exhibit secondary stress zones formed by insufficient energy attenuation or stress reconcentration. By analyzing the time lag characteristics of the surface subsidence trend change curve, the time period and extent that may trigger secondary subsidence are determined. After identifying the triggering areas, the stress state, surface displacement rate, and residual energy in these areas are comprehensively assessed to establish early warning indicators for the forward movement of surface subsidence risk. When the surface subsidence rate exceeds a preset threshold, or when an uneven trend in energy release occurs within the stress buffer zone, the system generates an early warning result indicating the potential risk of localized collapse, crack expansion, or slow subsidence. This warning result is transmitted through the surface monitoring network, enabling dynamic alerts for surface subsidence risk. This process transforms surface subsidence prediction from a static forecast to a forward-looking early warning based on dynamic changes in energy and stress, enabling real-time response to surface deformation and early risk identification.

[0089] This process dynamically couples seismic wave energy changes with surface deformation, enabling the prediction of surface subsidence above goaf areas to possess both temporal continuity and spatial accuracy. It can reflect the evolution of surface deformation caused by seismic wave energy transfer in real time. By combining updated surface subsidence trend maps with an early warning mechanism, it achieves a shift from passive observation to proactive identification of surface subsidence risks in goaf areas, providing a highly timely and reliable technical means for geological disaster prevention and control in mining areas.

[0090] Beneficial effect 1:

[0091] This invention, through meticulous acquisition of the uneven distribution characteristics of residual stress in goaf areas and the construction of a three-dimensional seismic wave propagation scenario, identifies potential energy amplification sensitive locations before seismic vibration occurs, transforming surface subsidence prediction from post-event analysis to pre-event perception and process tracking. Based on this, by forming a controllable stress buffer zone and introducing dynamic vibration detection and energy regulation methods, the rock strata remain in a coordinated stress response state throughout the seismic wave input process, effectively suppressing the cumulative amplification of energy in local areas. This fundamentally reduces the probability of secondary subsidence caused by stress redistribution, thereby improving the overall reliability and stability of surface subsidence prediction in goaf areas.

[0092] Benefit 2:

[0093] This invention systematically correlates stress changes during seismic wave vibration timing and energy regulation stages with surface subsidence response. By generating continuously updated surface subsidence trend maps, the surface deformation process can be continuously expressed and identified in advance. This method can accurately reflect the delayed and phased evolution characteristics of subsidence, determine risk areas before subsidence develops into a significant hazard, and output forward-looking early warning results. This provides a clear basis for the protection and safety decisions of surface facilities in mining areas, enabling surface subsidence prediction to not only have quantitative analysis capabilities but also dynamic early warning and risk indication value.

[0094] This invention provides, for example Figure 2 The surface subsidence prediction system for the goaf shown includes an energy distribution identification module, a stress buffer construction module, a vibration frequency comparison module, a seismic energy regulation module, and a subsidence monitoring and early warning module.

[0095] The energy distribution identification module collects the uneven characteristics of residual stress distribution in the goaf, constructs a three-dimensional seismic wave propagation scene, and divides the energy-accumulating areas based on the difference in rock density and elasticity.

[0096] The stress buffer construction module, based on the spatial distribution data of energy-prone areas, lays out graded stress relief holes and adopts a combination of directional pressure relief and deep grouting to form a controllable stress buffer zone at energy-prone sensitive locations and establish a stable residual stress background.

[0097] The vibration frequency comparison module, under the stable state of the stress buffer zone, embeds a multi-frequency vibration detection device to dynamically compare the input frequency of the seismic wave with the natural vibration frequency of the rock strata. Based on the comparison results, it identifies the resonance proximity signal and adjusts the decompression rhythm of the stress relief hole.

[0098] The seismic energy regulation module implements seismic wave energy regulation based on the resonance proximity signal obtained by vibration detection comparison, and reduces local energy peaks through reverse source intervention and phase misalignment interference.

[0099] The settlement monitoring and early warning module combines stress change information during the energy regulation phase to conduct surface settlement response monitoring, analyzes the correlation between dynamic stress sequences and seismic wave vibration time series, generates updated surface settlement trend maps, identifies secondary settlement triggering areas, and outputs early warning results for the forward movement of surface settlement risks.

[0100] The method for predicting surface subsidence in goaf areas provided in this embodiment of the invention is implemented through the aforementioned prediction system for surface subsidence in goaf areas. For details of the specific methods and procedures of the prediction system for surface subsidence in goaf areas, please refer to the embodiments of the method for predicting surface subsidence in goaf areas, which will not be repeated here.

[0101] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A method for predicting surface subsidence in goaf areas, characterized in that, Includes the following steps: Step 1: Collect the uneven distribution characteristics of residual stress in the goaf, construct a three-dimensional seismic wave propagation scene, and divide the energy accumulation zone according to the difference in rock density and elasticity. Step 2: Based on the spatial distribution data of energy-prone areas, graded stress relief holes are set up. A combination of directional pressure relief and deep grouting is used to form a controllable stress buffer zone at energy-prone sensitive locations and establish a stable residual stress background. Step 3: Under the stable state of the stress buffer zone, embed a multi-frequency vibration detection device to dynamically compare the input frequency of the seismic wave with the natural vibration frequency of the rock strata. Based on the comparison results, identify the resonance proximity signal and adjust the decompression rhythm of the stress relief hole. Step 4: Based on the resonance proximity signal obtained from vibration detection comparison, implement seismic wave energy regulation and reduce local energy peaks by means of reverse source intervention and phase misalignment interference. Step 5: Combine the stress change information during the energy regulation phase to conduct surface subsidence response monitoring, perform corresponding analysis between the dynamic stress sequence and the seismic wave vibration time series, generate an updated surface subsidence trend map, identify the secondary subsidence triggering area, and output the early warning result of the forward movement of surface subsidence risk.

2. The method for predicting surface subsidence in goaf areas according to claim 1, characterized in that, The steps for collecting data on the uneven distribution of residual stress in the goaf, constructing a three-dimensional seismic wave propagation scenario, and delineating energy-accumulating regions include: A comprehensive survey of the geological structure and residual stress state of the goaf and its surrounding areas was conducted. Multiple stress measuring points were arranged in the overlying strata, lateral surrounding rock and bottom rock mass. Stress parameters at different depths and directions were collected using borehole stress gauges, acoustic emission probes and core cleavage analysis methods to form a spatial distribution map of residual stress. Based on the spatial distribution data of residual stress, a three-dimensional seismic wave propagation scenario is constructed. The three-dimensional structure of the goaf and overlying rock strata is reconstructed in the spatial coordinate system. The residual stress data is mapped into the model, the seismic wave propagation path is set, and wave reflection boundaries and energy dissipation areas are established. Based on the differences in rock density and elasticity in the three-dimensional seismic wave propagation scenario, energy-accumulating regions are divided, and the wave impedance abrupt interface is spatially partitioned and assigned energy response coefficients and connectivity properties. Based on the energy transfer path of the energy-accumulating region, potential energy amplification sensitive locations are determined, forming spatial distribution data of the energy-accumulating region that includes energy response intensity and residual stress state.

3. The method for predicting surface subsidence in goaf areas according to claim 2, characterized in that, The steps involved in deploying graded stress relief holes, implementing directional pressure relief and deep grouting, and establishing a stable residual stress background based on the spatial distribution data of energy-prone areas include: Based on the spatial distribution data of energy-accumulating areas, the hole layout design is carried out in the stress-sensitive areas inside the goaf and the overlying strata. According to the energy response intensity, the energy-accumulating areas are divided into main control areas, secondary control areas and auxiliary areas. The spatial range, hole spacing, hole depth and hole diameter of the stress relief holes are determined to form a multi-layer stress diversion network covering the energy-accumulating areas. Targeted decompression operations are implemented. In the primary stress relief holes, controllable microcrack zones are formed by deep drilling blasting, mechanical enlargement, or hydraulic fracturing. In the secondary and tertiary stress relief holes, local energy is released by water pressure pulses or mechanical vibration to construct a spatial decompression gradient zone. Deep grouting is carried out using graded stress relief holes as channels. Inorganic grout is injected under pressure or at medium and low pressure at different hole positions to form a continuous reinforcement zone covering key nodes in areas prone to energy accumulation, and a controllable stress buffer zone is formed at energy-sensitive locations. By combining spatial distribution data of energy-prone areas, stress buffer zones are adjusted to achieve stress equilibrium. A stable residual stress background is established through micro-secondary grouting, ventilation and pumping, and surface backfilling.

4. The method for predicting surface subsidence in goaf areas according to claim 3, characterized in that, The steps involved in embedding a multi-frequency vibration detection device in the stable state of the stress buffer zone, performing frequency comparison, identifying resonance proximity signals, and adjusting the stress relief orifice depressurization rhythm include: Once the stress buffer zone is in a stable state, based on the hierarchical distribution of stress relief holes and the spatial morphology of energy-accumulating areas, the multi-frequency vibration detection device is embedded in the rock structure in sections. Main control detection points are set up around the primary stress relief holes, and secondary and auxiliary detection points are set up in the areas of secondary and tertiary stress relief holes, forming a monitoring network that decreases from the center outward. Dynamic comparison of seismic wave input frequency and natural vibration frequency of rock strata is carried out. Based on the frequency signals collected by the multi-frequency vibration detection device, the vibration amplitude, period changes and waveform characteristics of different monitoring points are correlated in time to identify resonance proximity signals and determine the spatial distribution range. Based on the comparison results, the stress relief hole pressure release rhythm is adjusted. Taking the first-level stress relief hole as the control center, the residual stress release speed is adjusted by controlling the pressure release interval and sequence. After the pressure relief rhythm is adjusted, the overall stress state of the stress buffer zone is coordinated, and the gas pressure, hydraulic transmission rate and grouting diffusion direction of the stress relief holes are controlled to form a stress distribution gradient that decreases from the inside to the outside.

5. The method for predicting surface subsidence in goaf areas according to claim 4, characterized in that, When coordinating the overall stress state of the stress buffer zone, the first-level stress relief hole is controlled to use an intermittent pressure relief method, the second-level stress relief hole is controlled to use a low-speed pressure relief method, and the third-level stress relief hole is controlled to perform periodic small-amplitude stress relief.

6. The method for predicting surface subsidence in goaf areas according to claim 4, characterized in that, The steps for implementing seismic wave energy modulation based on resonance proximity signals obtained from vibration detection comparison include: After obtaining the resonance proximity signal from vibration detection comparison, the target area for seismic wave energy modulation is determined based on the spatial range of the stress buffer zone. The time window and spatial location of the resonance proximity signal are extracted, and the spatial mapping relationship between the seismic wave propagation direction and the energy gradient is established. Based on the determination of the target area, reverse source intervention is implemented. Reverse source points are set up below the rock strata corresponding to the resonance area to control the energy release intensity, initiation time and wave direction of the source. The peak energy of the seismic wave is reduced and the energy distribution is balanced by reverse wave interference. Implement phase misalignment interference by setting up phase misalignment interference sources along the energy propagation path. By adjusting the phase of the interference wave to form a half-period difference with the main seismic wave, the peak energy of the main wave is weakened and the energy density is evenly distributed. Based on the completion of reverse source intervention and phase misalignment interference, the dynamic stress distribution and stress buffer response of the overlying strata are coordinated. By adjusting the release interval of the reverse source and the phase difference of the interference wave, the stress system is kept in dynamic equilibrium.

7. The method for predicting surface subsidence in goaf areas according to claim 6, characterized in that, In the coordinated implementation of reverse source intervention and phase misalignment interference, the reverse source point is set in the energy propagation reflection zone at the lower part of the stress buffer zone, and the interference source is set in the intersection area of ​​the energy reflection zone on the periphery of the stress buffer zone. The two are activated sequentially in time, and the release interval of the reverse source and the phase difference of the interference wave are dynamically adjusted according to the change of the peak energy of the seismic wave.

8. The method for predicting surface subsidence in goaf areas according to claim 6, characterized in that, The steps for conducting surface subsidence response monitoring and outputting early warning results for the forward movement of surface subsidence risk by combining stress change information during the energy regulation phase include: After the energy regulation phase is completed, stress change information generated during the seismic wave energy regulation process is collected. Through multiple stress sensing devices deployed inside the stress buffer zone, at the rock interface and on the surface, the stress change amplitude, direction and rate are recorded to form a dynamic stress sequence with time order. Surface settlement response monitoring is carried out based on dynamic stress sequence. A multi-layer displacement monitoring array is set up above the goaf to collect the changes in vertical and horizontal displacement of the surface in real time, and the surface deformation is analyzed in correspondence with the stress sequence of the stress buffer zone. By analyzing the correlation between dynamic stress sequences and seismic wave vibration time series, and by superimposing surface displacement monitoring data and stress change information to form a three-dimensional correlation between time, stress and settlement, a surface settlement trend update map is generated. Based on the updated surface subsidence trend map, secondary subsidence triggering areas are identified. By combining the residual stress distribution of the stress buffer zone with the changes in surface subsidence rate, an early warning index for the forward movement of surface subsidence risk is established, and the early warning results for the forward movement of surface subsidence risk are output.

9. The method for predicting surface subsidence in goaf areas according to claim 8, characterized in that, In the process of generating the updated surface subsidence trend map, the incremental surface displacement is analyzed in time series based on the synchronous relationship between the seismic wave vibration sequence and the stress release rate of the stress buffer zone. The change in subsidence velocity is represented by a color gradient in the map. By identifying high displacement gradient zones, the secondary subsidence triggering area is determined, thereby realizing the dynamic updating of surface subsidence trend and the identification of risk shift.

10. A prediction system for surface subsidence in goaf areas, used to implement the prediction method for surface subsidence in goaf areas as described in any one of claims 1-9, characterized in that, It includes an energy distribution identification module, a stress buffer construction module, a vibration frequency comparison module, an earthquake energy regulation module, and a settlement monitoring and early warning module; The energy distribution identification module collects the uneven characteristics of residual stress distribution in the goaf, constructs a three-dimensional seismic wave propagation scene, and divides the energy-accumulating areas based on the difference in rock density and elasticity. The stress buffer construction module, based on the spatial distribution data of energy-prone areas, lays out graded stress relief holes and adopts a combination of directional pressure relief and deep grouting to form a controllable stress buffer zone at energy-prone sensitive locations and establish a stable residual stress background. The vibration frequency comparison module, under the stable state of the stress buffer zone, embeds a multi-frequency vibration detection device to dynamically compare the input frequency of the seismic wave with the natural vibration frequency of the rock strata. Based on the comparison results, it identifies the resonance proximity signal and adjusts the decompression rhythm of the stress relief hole. The seismic energy regulation module implements seismic wave energy regulation based on the resonance proximity signal obtained by vibration detection comparison, and reduces local energy peaks through reverse source intervention and phase misalignment interference. The settlement monitoring and early warning module combines stress change information during the energy regulation phase to conduct surface settlement response monitoring, analyzes the correlation between dynamic stress sequences and seismic wave vibration time series, generates updated surface settlement trend maps, identifies secondary settlement triggering areas, and outputs early warning results for the forward movement of surface settlement risks.

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