A method and system for evaluating the bearing capacity of a coal mining area foundation

Abstract

The application discloses a kind of coal mining area ground bearing capacity zoning evaluation method and system, it is related to ground digital evaluation technical field.A kind of coal mining area ground bearing capacity zoning evaluation system, including have: geological information acquisition module, disturbance evaluation module, bearing calculation module, zoning discrimination module, ground treatment module and visual display module.The application constructs the regional division method based on soil layer structure parameter, and using the clustering and weighted fitting algorithm of main control soil layer type, the spatial expression ability of ground bearing capacity calculation model is improved;The boundary of region is reconstructed by disturbance influence, so that regional division is more in line with the continuity and discrimination boundary requirements of engineering practice.

Description

Technical Field

[0001] This invention relates to the field of digital foundation assessment technology, and in particular to a method and system for zoning evaluation of foundation bearing capacity in coal mining areas. Background Technology

[0002] The intensive development of coal resources has led to the widespread distribution of numerous coal mining subsidence areas in central and northern my country. Because the formation of coal mining goafs disrupts the integrity of the underground structure, the engineering characteristics of the overlying foundation change significantly, severely impacting the load-bearing safety and deformation control of building foundations, and hindering the redevelopment of subsidence areas and the utilization of land resources.

[0003] Currently, the evaluation of foundation bearing capacity in coal mining subsidence areas typically employs methods such as point-based bearing capacity analysis based on drilling and laboratory tests, manual empirical judgment based on the distribution of goaf areas, and integrated analysis methods using geological information systems (GIS). These methods cannot accurately quantify the attenuation effect of goaf disturbance on foundation bearing capacity, lack mechanisms for correction based on disturbance levels, and lack means to identify and model the influence of stratigraphic continuity and dominant soil layers, leading to unreasonable zoning and untargeted engineering recommendations. Furthermore, a closed-loop mechanism that automatically responds to target bearing capacity requirements and recommends treatment measures has not yet been established, and engineering suitability assessments and foundation reinforcement decisions heavily rely on manual judgment. Summary of the Invention

[0004] This invention proposes a method and system for evaluating the bearing capacity of coal mining area foundations by integrating multi-source geological data, quantitatively assessing the impact of mining subsidence, and combining regional soil structure characteristics for bearing capacity correction and zoning. This results in constructability assessment and treatment recommendations for engineering applications, improving the consistency, traceability, and engineering guidance value of the evaluation results.

[0005] A method for zoning and evaluating the bearing capacity of foundations in coal mining areas includes:

[0006] Geological information, including drilling columnar sections, cross-hole CT geophysical data, ground subsidence monitoring data, and mining data, was collected, and coordinate registration and standardization were performed on the data to obtain goaf characteristics and construct a three-dimensional geological model.

[0007] Based on the characteristics of mining subsidence, the three-dimensional geological model is divided into several regions with soil structure parameters, and a mining subsidence disturbance zone model is constructed to assess the disturbance level of each region.

[0008] Based on the soil structure parameters, the original bearing capacity of the foundation in each region is calculated, and the original bearing capacity is corrected according to the corresponding disturbance level to obtain the corrected bearing capacity value of each region.

[0009] Based on the corrected bearing capacity value, each area is divided, and a zoning map of foundation bearing capacity level and corresponding engineering suggestion map are output;

[0010] The system obtains the target bearing capacity requirement input by the user, automatically compares it with the corrected bearing capacity value of each area, and if the target bearing capacity requirement is not met, it matches the corresponding treatment technology from the preset foundation treatment rule library according to the disturbance level and soil structure parameters of the area, and judges whether the target bearing capacity requirement can be met after treatment, and outputs the corresponding construction suitability assessment results and foundation treatment suggestions.

[0011] The layers of foundation bearing capacity level zoning map, suitability analysis results and foundation treatment recommendations are spatially overlaid, and the resulting visualization layer results can be used for displaying 3D geological models.

[0012] As a preferred embodiment of the present invention, dividing the three-dimensional geological model into several regions with soil structure parameters includes:

[0013] In a three-dimensional geological model, regular or irregular three-dimensional grid cells are constructed, and soil structure parameters of each cell are extracted. Adjacent cells with a main soil layer type difference of less than a preset threshold are merged into a continuous region. The merging process adopts a clustering rule based on the minimum cell number threshold to achieve both spatial continuity and engineering discrimination boundary. The soil structure parameters of the region are the weighted average of the soil structure parameters of its constituent cells based on volume weight, and are fitted and expressed at the regional scale for subsequent bearing capacity calculation and suitability assessment.

[0014] As a preferred embodiment of the present invention, the soil structure parameters include:

[0015] The types, thicknesses, natural unit weights, void ratios, liquid limits, plasticity indices, compression moduli, internal friction angles, cohesion, foundation saturation, and groundwater depths of different soil layers within each spatial unit;

[0016] The acquisition of the dominant soil layer type includes selecting the soil layer with the largest thickness within the spatial unit and continuously distributed within the effective depth range; if the soil layer is a soft and compressible soil layer, then a weighted evaluation is performed based on its compression modulus and void ratio, and the soil layer that plays a dominant role in bearing capacity control is selected as the dominant soil layer type of the unit.

[0017] As a preferred technical solution of the present invention, the construction of the goaf disturbance zone model includes:

[0018] On the basis of dividing regions in the three-dimensional geological model, the vertical depth and horizontal distribution range of the regional disturbance influence scope are determined according to the depth of the goaf, spatial range, roof structure parameters and backfill state in the goaf characteristics of each region, as well as the settlement rate and settlement deformation curve characteristics reflected in the ground settlement monitoring data. Then, through the contact structure relationship between the goaf area and its overlying soil mass in the three-dimensional geological model, the regional boundary reconstruction based on the disturbance influence is completed, and the soil layer structure parameters are updated to form a goaf disturbance zone model in the form of a continuum. Based on the disturbance response weight model, the disturbance impact assessment is carried out on each region after the regional boundary reconstruction to obtain the disturbance level.

[0019] As a preferred technical solution of the present invention, the disturbance response weight model is constructed according to the following parameters:

[0020] The goaf depth H, the horizontal span L in the spatial range, the structural integrity rate R of the roof rock stratum, the compactness C of the backfill, the settlement rate V and the settlement curvature K of each region are extracted. The above parameters are subjected to dimensionless processing to obtain standardized parameters xH, xL, xR, xC, xV and xK, wherein reverse standardization is adopted for R and C. Based on the historical monitoring data of the preset sample regions, the entropy weight method is used to determine the weight wi of each standardized parameter, which satisfies Σwi=1. The standardized parameters corresponding to each region are substituted into the disturbance response weight model, the comprehensive disturbance influence value D is calculated according to D=Σ(w_i·x_i), and each region is divided into a plurality of disturbance levels according to the clustering classification rule.

[0021] As a preferred technical solution of the present invention, the obtaining of the corrected bearing capacity value of each region includes:

[0022] The original bearing capacity value q0 is obtained by calculation using the empirical bearing capacity formula based on the soil layer structure parameters of each region. The disturbance correction coefficient k is determined according to the comprehensive disturbance influence value D of the region. The disturbance correction coefficient k is a monotonically decreasing mapping function of the comprehensive disturbance influence value D and satisfies 0<k≤1, and the corrected bearing capacity value q'=k·q0.

[0023] As a preferred technical solution of the present invention, the foundation bearing capacity grade zoning map and the corresponding engineering suggestion map include:

[0024] The modified bearing capacity value of each region is compared with the preset bearing capacity discrimination threshold. According to the construction bearing capacity requirements, the regions are divided into three categories: construction zone, restricted construction zone, and prohibited construction zone. The construction zone corresponds to the region where the modified bearing capacity value is higher than the upper limit threshold, the restricted construction zone corresponds to the region where the modified bearing capacity value is between the upper and lower limits threshold, and the prohibited construction zone corresponds to the region where the modified bearing capacity value is lower than the lower limit threshold. Based on the regional division, the corresponding foundation bearing capacity level zoning map is generated. Combined with the disturbance level, the main controlling soil layer type and the original bearing capacity value, the engineering suggestion map containing construction restrictions, foundation treatment suggestions and precautions is output.

[0025] As a preferred embodiment of the present invention, the construction suitability assessment results and foundation treatment recommendations include:

[0026] For areas that do not meet the user's target bearing capacity requirements, a regional stability response vector is constructed by combining the disturbance level and soil structure parameters. This vector is then input into a foundation treatment rule base constructed based on rule matching and engineering experience factors to retrieve applicable treatment technology combinations. The simulation results of the improved bearing capacity are compared with the target bearing capacity requirements to determine the technical feasibility. If the feasibility is met, foundation treatment suggestions are generated, including treatment methods, applicable soil conditions, construction points, and the expected improvement in bearing capacity. At the same time, the construction suitability assessment results of the corresponding area are output as an auxiliary basis for judgment.

[0027] A zoning evaluation system for the bearing capacity of foundations in coal mining areas includes:

[0028] Geological information acquisition module: Acquires geological information, obtains characteristics of mining subsidence, and constructs a three-dimensional geological model;

[0029] Disturbance assessment module: Based on the characteristics of mining subsidence, the three-dimensional geological model is divided into several regions with soil structure parameters, and a mining subsidence disturbance zone model is constructed to assess the disturbance level of each region.

[0030] Bearing capacity calculation module: Based on soil structure parameters, calculate the original bearing capacity value of the foundation in each area, and correct the original bearing capacity according to the corresponding disturbance level to obtain the corrected bearing capacity value of each area;

[0031] Zoning Module: Divides each area according to the modified bearing capacity value, and outputs a zoning map of foundation bearing capacity level and corresponding engineering suggestion map;

[0032] Foundation treatment module: It obtains the target bearing capacity requirement input by the user, automatically compares it with the corrected bearing capacity value of each area, and if it does not meet the target bearing capacity requirement, it matches the corresponding treatment technology from the preset foundation treatment rule library according to the disturbance level and soil structure parameters of the area, and judges whether the target bearing capacity requirement can be met after treatment, and outputs the corresponding construction suitability assessment results and foundation treatment suggestions.

[0033] Visualization module: Spatially overlays the layers of foundation bearing capacity level zoning map, suitability analysis results and foundation treatment suggestions, and outputs the visualization layer results that can be used for displaying 3D geological models.

[0034] The present invention has the following advantages:

[0035] This invention integrates drilling columnar sections, cross-hole CT geophysical data, ground subsidence monitoring data, and mining data to establish a three-dimensional geological model under a unified coordinate system, thereby achieving spatial fusion and standardized processing of multi-source heterogeneous geological information and enhancing the information coverage and consistency of foundation feature identification in goaf areas.

[0036] This invention improves the spatial representation capability of the foundation bearing capacity calculation model by constructing a region division method based on soil structure parameters and using clustering and weighted fitting algorithms based on the dominant soil layer type. By reconstructing the boundary of the region through disturbance, the region division is made more in line with the continuity and boundary discrimination requirements of engineering practice.

[0037] This invention establishes a weighted model for the response to goaf disturbance. It weights and superimposes disturbance factors such as goaf depth, horizontal span, roof structure integrity rate, backfill compaction degree, settlement rate, and settlement curvature after dimensionless processing. The weights can be determined using the entropy weight method or the analytic hierarchy process (AHP) combined with a consistency test, thereby obtaining a comprehensive disturbance impact value and classifying it. Furthermore, using the comprehensive disturbance impact value as the independent variable, a bearing capacity correction coefficient is determined through a monotonically decreasing mapping function calibrated by field tests or historical engineering databases. This achieves dynamic correction of the bearing capacity, improving the model's applicability and traceability under goaf disturbance scenarios.

[0038] This invention compares the corrected bearing capacity value with a preset bearing capacity threshold to form three types of zones: construction zone, restricted construction zone, and prohibited construction zone, and outputs corresponding engineering suggestion diagrams, thus realizing an intuitive mapping and practical application of bearing capacity results and engineering feasibility judgment.

[0039] This invention obtains the target bearing capacity requirements set by the user, compares and judges the regional modified bearing capacity, constructs a stability response vector, and inputs it into a processing rule base based on rule matching and engineering experience factor weighting. This realizes automatic suitability assessment and reinforcement scheme recommendation for areas that do not meet the requirements, thereby improving the efficiency and intelligence level of engineering auxiliary design. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are only schematic diagrams of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0041] Figure 1 This is a typical representative drilling column diagram used in the embodiments of the present invention;

[0042] Figure 2 This is a cross-sectional view used in an embodiment of the present invention;

[0043] Figure 3 This is a zoning diagram of the foundation bearing capacity used in an embodiment of the present invention;

[0044] Figure 4 This is a schematic diagram of a coal mining area foundation bearing capacity zoning evaluation system used in an embodiment of the present invention. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0046] Example 1: A method for evaluating the zoning of foundation bearing capacity in coal mining areas, referencing... Figure 1 , 2 As shown in Figure 3, the steps include:

[0047] Step S1: Collect drilling columnar section data (e.g., ...) Figure 1 Geological information from cross-hole CT geophysical data, ground subsidence monitoring data, and mining data (as shown) was collected, and coordinate registration and standardization were performed on them to obtain goaf characteristics and construct a three-dimensional geological model.

[0048] The drilling columnar section is a layered geological record map obtained from boreholes laid out in the study area. The record includes the soil layer distribution sequence, thickness, lithological description, groundwater level, standard penetration test (N value), and various geotechnical engineering parameters (such as natural unit weight, void ratio, liquid limit, plasticity index, compression modulus, internal friction angle, cohesion, etc.), which are used to construct a soil layer structure parameter database for spatial units.

[0049] The cross-hole CT geophysical data refers to the use of a distributed borehole layout to lay out multiple boreholes in and around the goaf, and to perform high-resolution seismic wave velocity imaging between each borehole to obtain transverse profile wave velocity anomaly maps, which are used to determine information such as the boundary of the goaf, the integrity of the roof structure, and the backfill status, providing support for subsequent goaf feature identification and disturbance response modeling.

[0050] The ground subsidence monitoring data includes subsidence sequences from high-frequency GNSS monitoring points, precise leveling routes, and InSAR interferometric radar data. The main parameters include subsidence rate, cumulative subsidence, subsidence deformation curve and curvature, which are used to identify surface deformation characteristics and, in combination with time series analysis, determine whether the mining subsidence disturbance is still in an active stage.

[0051] The mining data includes historical mining maps, mining sequence, mining height, mining depth, roof lithology distribution, mining methods (such as full mining or roof preservation with pillars) from mining enterprises or management units, as well as the type and compaction grade of backfill materials, providing raw data for constructing a model of the goaf disturbance zone.

[0052] Geological information obtained from different data sources has different coordinate references, unit systems, and time stamps. In this embodiment, spatial registration is performed using a unified GIS coordinate system (WGS84) to overlay borehole locations, monitoring points, mining maps, etc., onto the same spatial frame. Geophysical data is voxelized, wave velocity values ​​are uniformly converted into rock mass integrity indicators, and then converted into a grid format that can be accessed by the geological model. Drilling data is standardized, including missing value imputation, unit unification, and invalid layer identification, to form a structured data table for subsequent modeling.

[0053] The goaf characteristics refer to the spatial distribution information of the goaf area derived from cross-hole CT imaging, mining data, and settlement monitoring results. This includes: goaf depth (from the surface to the top of the goaf layer); the spatial extent of the goaf, including its horizontal range and thickness; roof structural parameters (number, thickness, and integrity of roof strata); backfill status (existence of backfill and compaction degree of backfill material); and disturbance activity indicators (such as the proportion of active settlement points, settlement rate, and second-order deformation curvature). These characteristics will be used as inputs for the disturbance level assessment model and the disturbance zone spatial reconstruction algorithm.

[0054] Based on the registered geological information, 3D modeling software (such as GOCAD) is used to complete stratigraphic interface interpolation, layer construction, and attribute assignment to generate a 3D geological model with integrated structural attributes. Each spatial unit in the model contains nested soil structure parameter fields and mining subsidence-related identifier fields to support subsequent regional division, bearing capacity calculation, and visualization overlay. The 3D model uses a unified grid voxel as its basic data structure, supports structured querying and spatial overlay, and has scalability and engineering deployment capabilities.

[0055] After the three-dimensional geological model is generated, independent boreholes, in-situ test points, or subsequent monitoring points that were not involved in the modeling are selected as validation sets. The identification results of the goaf boundary, roof integrity rate, backfill status, and main control soil layer type are cross-checked to form a validation report containing indicators such as boundary position deviation and parameter relative error. The results can be compared with the two-dimensional / three-dimensional model results based on only a single drilling data to reflect the improvement of information coverage and result consistency brought about by multi-source fusion.

[0056] Step S2: Divide the three-dimensional geological model into several regions with soil structure parameters according to the characteristics of mining subsidence, construct a mining subsidence disturbance zone model, and evaluate the disturbance level of each region.

[0057] The division of the three-dimensional geological model into several regions with soil structure parameters includes:

[0058] In the constructed 3D geological model, the basic dividing units within the model body are first defined based on the principle of spatial consistency. These units are either regular raster units (such as equilateral cube voxels) or irregular 3D mesh units (such as Delaunay volume units controlled by borehole spacing or isopyropleth units driven by geological interfaces). Each unit serves as the basic operational unit for subsequent geological attribute assignment and engineering analysis. For each 3D unit, the soil layer structure parameters contained within it are extracted, including but not limited to: the type of each soil and rock layer distributed within the unit (lithology or engineering classification); the thickness and relative burial depth of each soil layer; the physical and mechanical properties of each soil layer (such as natural unit weight, void ratio, liquid limit, plasticity index, compression modulus, internal friction angle, and cohesion); and the groundwater level and saturation state at that unit. The sources for obtaining the soil layer structure parameters are referenced. Figure 2 As shown, Figure 2 It includes the distribution and thickness of various soil layers in a typical profile.

[0059] To enhance the engineering adaptability of the model area, unit clustering and merging are performed based on the dominant soil layer type. The dominant soil layer type refers to the key soil layer that plays a leading role in the bearing capacity characteristics of the foundation. The selection criteria are as follows: In each spatial unit, the soil layer with the largest thickness and continuous distribution within the effective bearing depth (e.g., 0–10m below the surface) is identified; if this layer is a soft compressible soil layer (such as silty clay or silty mud), its compression modulus and void ratio are further combined, and a weighted evaluation method is used to identify the soil layer that plays a leading role in foundation settlement control and bearing capacity contribution, which is then regarded as the dominant soil layer type of the unit.

[0060] Subsequently, a region partitioning operation based on the aggregation rule of the main soil layer type similarity is performed. Adjacent units are merged into the same region if they meet the following conditions: the main soil layer type is consistent, or the difference is less than the preset lithological similarity threshold; the variation of various soil layer structural parameters in an engineering sense does not exceed the specified range; and the spatial distribution is connectable. The merging adopts a clustering rule based on the minimum number of units threshold, that is, each delineated region should contain no less than the preset number of spatial units (e.g., 10 units) to ensure that the model has sufficient spatial representativeness and avoids the influence of local outliers.

[0061] Finally, the soil structure parameters of each region are statistically calculated using the volume-weighted average of the parameters of each unit contained therein, and expressed as a continuous attribute field at the regional scale through interpolation fitting, which is used for subsequent calculation of original bearing capacity and foundation suitability assessment.

[0062] The construction of the goaf disturbance zone model includes:

[0063] Based on the already defined three-dimensional geological model areas, and according to the goaf characteristics of each area, including goaf depth, spatial range, roof structure parameters, and backfill status, combined with the settlement rate and settlement deformation curve characteristics in the settlement monitoring data, the following steps are performed:

[0064] Determining the scope of disturbance impact: Vertical depth: Based on the depth of the goaf in each area and combined with ground subsidence monitoring results (such as the location and time of maximum subsidence), the vertical disturbance depth of the goaf area is estimated using a spatiotemporal interpolation model. The maximum depth of the vertical disturbance impact is defined by the second-order deformation rate of the subsidence curve. Horizontal extent: Utilizing the horizontal expansiveness of the goaf area in each area (determining the extension boundary through mining data and subsidence monitoring data), and combining the characteristics of ground subsidence rate and subsidence deformation curve, the distance of the disturbance impact extending in all directions is assessed.

[0065] Contact structure relationship and boundary reconstruction: Based on the contact structure relationship between the mined-out area and its overlying soil, the boundary of the disturbed area is accurately reconstructed by calculating the soil contact surface of each region in the three-dimensional geological model, forming a continuum model so that the soil structure parameters can be updated in the region in the future.

[0066] Boundary reconstruction requires comprehensive consideration of: the actual mining area of ​​the goaf, the deformation and fragmentation of the roof strata, the compaction degree of the backfill, and the cumulative effect of known settlement deformation. The final generated goaf disturbance zone model can intuitively reflect the mechanical differences and interrelationships between the soil inside and outside the goaf.

[0067] Soil structure parameters updated:

[0068] After boundary reconstruction, the soil structural parameters (such as compression modulus, internal friction angle, cohesion, etc.) within the goaf will be updated based on the newly defined disturbance zone boundary and the settlement curvature of each area. This step is crucial, as it ensures that the disturbance corrects the soil's mechanical properties, such as the increased compressibility or decreased strength that may occur in weak soil layers after disturbance.

[0069] Disturbance impact assessment and disturbance level acquisition:

[0070] The disturbance response weighting model is the core of this step. It uses a variety of parameters (such as goaf depth, spatial range, roof structure integrity, etc.) for weighted evaluation to calculate the comprehensive disturbance impact value for each region.

[0071] The disturbance response weight model is constructed based on the following parameters:

[0072] Goaf depth: Goaf depth is one of the key parameters for assessing the degree of disturbance impact. The greater the goaf depth, the greater the likelihood and extent of soil disturbance. In the model, this depth is used as a weighting parameter, usually weighted by a linear or nonlinear functional relationship between goaf depth and settlement curvature.

[0073] Horizontal span within the spatial range: Assess the scalability of the impact of the horizontal range of the mined-out area on the foundation bearing capacity. A wide range of mined-out areas will have a greater impact on the foundation stability of the surrounding areas, and therefore it is given a higher weight.

[0074] Roof structure parameters and integrity: The integrity of the roof structure determines the stability of the overlying soil in the goaf. If the roof rock structure is relatively fragile or broken, the disturbance effect is more significant. Therefore, the integrity of the roof structure is also an important parameter in the disturbance response model.

[0075] Backfill compaction in the backfill state: The compaction degree of backfill material directly affects the density and strength of the soil. Low compaction degree of backfill layer will lead to greater settlement and deformation, and increase the disturbance effect.

[0076] Settlement rate: The rate of settlement is one of the indicators for judging the activity level of disturbance. The higher the settlement rate, the stronger the disturbance is being experienced, and the higher the weight should be given to the disturbance level.

[0077] Settlement curvature in settlement deformation curve characteristics: Settlement curvature can reflect the concentration and rate of change of surface settlement. Especially in areas with large settlement curvature, the deformation control of the foundation soil layer is particularly important and affects the assessment of disturbance level.

[0078] The above parameters are substituted into the disturbance response weighting model for weighted superposition, and the comprehensive disturbance impact value of each region is calculated based on the contribution coefficient of each parameter.

[0079] Establish a disturbance response weight model. Extract the following parameters for each region: goaf depth H, horizontal span L, roof rock structure integrity R, backfill compaction C, settlement rate V, and settlement curvature K.

[0080] The aforementioned disturbance factors are dimensionless to obtain standardized quantities xi: for positive disturbance factors H, L, V, and K, x = (p - p_min) / (p_max - p_min); for the suppression disturbance factors, roof integrity rate R and backfill compaction degree C, reverse standardization x = 1 - (p - p_min) / (p_max - p_min). Based on historical monitoring data of the preset sample area, the entropy weight method is used to determine the weights wi (Σwi = 1), thereby obtaining the objective source and traceability of the weights.

[0081] The standardized quantities are substituted into the disturbance response weight model to calculate the comprehensive disturbance impact value D=Σ(wi·xi). Based on the distribution of D, the disturbance level threshold is determined using the K-means clustering rule, and the region is divided into mild, moderate and severe disturbance levels.

[0082] Step S3: Based on the soil structure parameters, calculate the original bearing capacity value of the foundation in each area, and correct the original bearing capacity according to the corresponding disturbance level to obtain the corrected bearing capacity value of each area.

[0083] The process of obtaining the corrected bearing capacity values ​​for each region includes:

[0084] The original bearing capacity value is calculated based on the soil structure parameters of each region using an empirical formula for bearing capacity. The original bearing capacity value is corrected according to the disturbance level of the region. The correction method is to perform linear or nonlinear attenuation adjustment according to the correction coefficient corresponding to the disturbance level. The correction coefficient is determined based on the comprehensive value of disturbance influence output by the disturbance response weight model.

[0085] The original bearing capacity value refers to the foundation bearing capacity index calculated solely based on the constitutive properties and geometric structure of the soil layer without considering the impact of mining subsidence. It reflects the ability of the regional soil layer to support the overlying load in its natural state.

[0086] All parameters on which the original bearing capacity value depends are derived from the regional soil layer structure parameters obtained after unit merging and weighted fitting in step S2, including but not limited to: natural unit weight (γ), cohesion (c), internal friction angle (φ), groundwater depth (hw), soil layer thickness and main control soil layer properties. After being processed by the porous media effective stress theory, the above parameters are imported into the empirical bearing capacity calculation model as inputs. An empirical formula for foundation bearing capacity that conforms to regional geological conditions is selected, for example, the modified Terzaghi bearing capacity formula recommended in the design code for building foundation or the layered weighted bearing capacity calculation method recommended by the code, and the calculation model is determined according to the engineering characteristics of the main control soil layer. If there is a multi-layer heterogeneous soil layer structure in the region, the equivalent foundation method or the foundation base shear stress control method is adopted for multi-layer merging, so as to ensure that the calculated bearing capacity value can fully represent the regional foundation response behavior.

[0087] To truly reflect the weakening effect of goaf disturbance on foundation performance, a disturbance level is introduced as an adjustment factor to correct the original bearing capacity value, which specifically includes the following steps:

[0088] The disturbance correction coefficient k is determined based on the comprehensive disturbance influence value D output by the disturbance response weight model in step S2, where k is a monotonically decreasing mapping function of D and satisfies 0 < k ≤ 1, the corrected bearing capacity value q' = k·q0, where q0 is the regional original bearing capacity value. An exponential function is adopted as the mapping function, for example: k = max(k_min, exp(-a·D^b)), where a, b and k_min are determined by fitting and calibrating the ratio of the measured bearing capacity obtained from independent field bearing tests (plate load tests), static cone penetration tests or standard penetration tests to q0.

[0089] When the calibration samples are insufficient, the initial parameters of the mapping function can be given based on the historical engineering database or the reduction coefficient interval recommended by the code, and updated in a rolling manner after new monitoring or test data are obtained, so that the correction coefficient has traceable sources and verifiability.

[0090] Step S4: Divide each region according to the corrected bearing capacity value, and output the foundation bearing capacity grade zoning map (e.g. Figure 3 as shown in the figure) and the corresponding engineering suggestion map;

[0091] The foundation bearing capacity grade zoning map and the corresponding engineering suggestion map include:

[0092] The modified bearing capacity value of each region is compared with the preset bearing capacity discrimination threshold. According to the construction bearing capacity requirements, the regions are divided into three categories: construction zone, restricted construction zone, and prohibited construction zone. The construction zone corresponds to the region where the modified bearing capacity value is higher than the upper limit threshold, the restricted construction zone corresponds to the region where the modified bearing capacity value is between the upper and lower limits threshold, and the prohibited construction zone corresponds to the region where the modified bearing capacity value is lower than the lower limit threshold. Based on the regional division, the corresponding foundation bearing capacity level zoning map is generated. Combined with the disturbance level, the main controlling soil layer type and the original bearing capacity value, the engineering suggestion map containing construction restrictions, foundation treatment suggestions and precautions is output.

[0093] The aforementioned zoning refers to classifying areas based on their modified bearing capacity values ​​and foundation stability requirements. Specific steps include setting bearing capacity thresholds according to the foundation design requirements of different building types, recommended values ​​in codes, and differences in site usage.

[0094] Upper limit of carrying threshold ( If the regional bearing capacity is higher than this value, it can meet the requirements of conventional engineering construction.

[0095] Lower limit carrying threshold ( If the carrying capacity of the area is lower than this value, construction projects must be restricted or prohibited.

[0096] Middle section ( This is the critical state zone of bearing capacity, which requires further technical demonstration or treatment measures.

[0097] Classification rule explanation: Construction area, corrected bearing capacity value ≥ It meets the requirements for construction safety and stability, requiring no special reinforcement measures; within the construction area, the corrected bearing capacity value ∈ [ , There are certain engineering risks involved, and the feasibility of construction needs to be assessed further after considering foundation treatment techniques; in prohibited construction areas, the bearing capacity value should be revised accordingly. The bearing capacity is insufficient or the geological conditions are complex, making construction impossible.

[0098] Using GIS spatial analysis tools or 3D geological modeling platforms, regions are compared with carrying capacity thresholds one by one, and classification is achieved through logical judgment and classification labeling.

[0099] The foundation bearing capacity zoning map is a visual representation of each region in the 3D geological model, based on the aforementioned classification results. Specifically, it includes: a color-coded zoning layer, using different colors or transparency to render the three types of regions graphically, such as green for construction zones, yellow for restricted construction zones, and red for prohibited construction zones; and spatial information annotation, adding region ID, corrected bearing capacity value range, main controlling soil layer type, and disturbance level information as an appendix to each region, enhancing the data meaning expression capability of the spatial layer.

[0100] The proposed engineering map is an output that further integrates geological risk information and engineering countermeasures suggestions based on the foundation bearing capacity zoning map. It mainly includes: Recommendation generation logic: Correcting bearing capacity values ​​based on the region; identifying the main controlling soil layer type (e.g., soft soil, fill, gravel layer); disturbance level (affecting construction technology and stability); original bearing capacity value (providing a mechanical baseline reference before intervention); and a comprehensive assessment of the construction risk level and necessary precautions. Recommended output content includes: construction restrictions, whether building types need to be restricted (e.g., high-rise, large-span structures); foundation treatment suggestions, applicable treatment methods (e.g., grouting reinforcement, preloading consolidation, pile foundation replacement); and precautions, providing guidance on monitoring, construction sequence, and backfill material control.

[0101] Engineering suggestion diagrams can have text annotations or legend blocks added to spatial layers to achieve an intuitive and visual expression of suggestion information, and support PDF output and import into engineering drawing platforms.

[0102] Step S5: Obtain the target bearing capacity requirement input by the user, automatically compare the corrected bearing capacity value of each area, and if the target bearing capacity requirement is not met, match the corresponding treatment technology from the preset foundation treatment rule library according to the disturbance level and soil structure parameters of the area, and determine whether the target bearing capacity requirement can be met after treatment, and output the corresponding construction suitability assessment results and foundation treatment suggestions.

[0103] The suitability assessment results and foundation treatment recommendations include:

[0104] For areas that do not meet the user's target bearing capacity requirements, a regional stability response vector is constructed by combining the disturbance level and soil structure parameters. This vector is then input into a foundation treatment rule base constructed based on rule matching and engineering experience factors to retrieve applicable treatment technology combinations. The simulation results of the improved bearing capacity are compared with the target bearing capacity requirements to determine the technical feasibility. If the feasibility is met, foundation treatment suggestions are generated, including treatment methods, applicable soil conditions, construction points, and the expected improvement in bearing capacity. At the same time, the construction suitability assessment results of the corresponding area are output as an auxiliary basis for judgment.

[0105] The target bearing capacity requirement refers to the lower limit of the regional foundation bearing capacity given by the user based on factors such as building type, foundation design standards, and engineering grade. The system uses this as a benchmark value to compare and adjust the bearing capacity value for each region. This parameter can be entered through a graphical interface or imported from an external design parameter file.

[0106] The system automatically compares the corrected bearing capacity values ​​of all regions with the target bearing capacity values, marks all regions with values ​​below the target, and proceeds to the next recommended processing step. These regions typically have high disturbance levels or adverse geological conditions such as soft soil layers.

[0107] For each region that does not meet the requirements, the following data dimensions are extracted to construct a stability response vector to support the rule matching process: disturbance level (output from the disturbance response weight model); dominant soil layer type; structural parameters of each soil layer (such as compression modulus, cohesion, liquid limit, void ratio, etc.); original bearing capacity and corrected bearing capacity values; and spatial location and volume information of the region in the 3D geological model. The stability response vector is a digital representation of the geological-mechanical-disturbance characteristics of the region, used to drive the subsequent matching calculation process of the rule base.

[0108] The foundation treatment rule base is a crucial module for recommending engineering intervention schemes, featuring the following characteristics: Rule source: constructed based on industry engineering experience, existing construction schemes, design specifications, and numerical simulation results. Input structure: receives stability response vectors as input; Matching mechanism: based on rule matching (if-then) and weighted recommendations using engineering experience factors. For example: if the controlling soil layer is silty clay with high disturbance level and low compression modulus → composite foundation grouting reinforcement is recommended; if the settlement rate is fast and the backfill compaction degree is low → dense compaction combined with shallow pile foundation replacement is recommended. Output content: 1 to n matched foundation treatment combinations; applicable conditions, typical treatment range, and expected bearing capacity improvement after simulation for each scheme; comparison results of the difference with the target bearing capacity.

[0109] For each proposed solution, the estimated bearing capacity is simulated or compared using a table. If the target bearing capacity requirement is met, the solution is deemed feasible, and the following information is output: treatment method (grouting, replacement, compaction, pile foundation composite, preloading consolidation, etc.); applicable soil conditions (soil layer thickness, upper and lower limits of soil property indicators); key construction points (construction depth, compaction level, grouting mix ratio, etc.); expected improvement effect (including expected bearing capacity increase, settlement rate change, etc.); and auxiliary evaluation results (whether construction suitability is achieved, whether safety redundancy is met), forming a clear judgment conclusion. If all treatment combinations still fail to meet the target bearing capacity requirement, the area is designated as unsuitable for construction, and this judgment result is automatically pushed to step S6 for visual marking.

[0110] Step S6: Spatially overlay the layers of the foundation bearing capacity level zoning map, the suitability analysis results, and the foundation treatment recommendations, and output a visualization layer result that can be used for displaying the three-dimensional geological model.

[0111] Based on a Geographic Information System (GIS) and a 3D geological modeling platform, the data generated in steps S4 and S5 are overlaid and integrated at the layer level to form the final visualization output. Overlaid layers include, but are not limited to: a foundation bearing capacity level zoning map (construction area, restricted construction area, prohibited construction area); a construction suitability assessment result map (meets / does not meet the target bearing capacity); a foundation treatment suggestion distribution map (marking areas with recommended treatment schemes); and a 3D geological structure and disturbance level spatial distribution map.

[0112] Example 2: A zoning evaluation system for the bearing capacity of foundations in coal mining areas (see [link]). Figure 4 As shown, it includes the following modules:

[0113] Geological information acquisition module: Acquires geological information, obtains characteristics of mining subsidence, and constructs a three-dimensional geological model;

[0114] Disturbance assessment module: Based on the characteristics of mining subsidence, the three-dimensional geological model is divided into several regions with soil structure parameters, and a mining subsidence disturbance zone model is constructed to assess the disturbance level of each region.

[0115] Bearing capacity calculation module: Based on soil structure parameters, calculate the original bearing capacity value of the foundation in each area, and correct the original bearing capacity according to the corresponding disturbance level to obtain the corrected bearing capacity value of each area;

[0116] Zoning Module: Divides each area according to the modified bearing capacity value, and outputs a zoning map of foundation bearing capacity level and corresponding engineering suggestion map;

[0117] Foundation treatment module: It obtains the target bearing capacity requirement input by the user, automatically compares it with the corrected bearing capacity value of each area, and if it does not meet the target bearing capacity requirement, it matches the corresponding treatment technology from the preset foundation treatment rule library according to the disturbance level and soil structure parameters of the area, and judges whether the target bearing capacity requirement can be met after treatment, and outputs the corresponding construction suitability assessment results and foundation treatment suggestions.

[0118] Visualization module: Spatially overlays the layers of foundation bearing capacity level zoning map, suitability analysis results and foundation treatment suggestions, and outputs the visualization layer results that can be used for displaying 3D geological models.

[0119] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for zoning and evaluating the bearing capacity of foundations in coal mining areas, characterized in that, comprising: collecting geological information including drilling histograms, cross-hole CT geophysical prospecting data, land subsidence monitoring data and mine excavation data, performing coordinate registration and standardization processing thereon, acquiring goaf features, and constructing a three-dimensional geological model; dividing the three-dimensional geological model into a number of regions with soil layer structure parameters according to the goaf features, constructing a goaf disturbance zone model, and evaluating the disturbance level of each region; calculating the original bearing capacity value of the foundation of each region based on the soil layer structure parameters, and correcting the original bearing capacity according to the corresponding disturbance level to obtain the corrected bearing capacity value of each region; the step of obtaining the corrected bearing capacity value of each region comprises: acquiring the original bearing capacity value q0 by using a bearing capacity empirical formula based on the soil layer structure parameters of each region; determining a disturbance correction coefficient k according to the comprehensive disturbance influence value D, wherein the disturbance correction coefficient k is a monotonically decreasing mapping function of the comprehensive disturbance influence value D and satisfies 0<k≤1, and the corrected bearing capacity value q'=k·q0; dividing each region according to the corrected bearing capacity value, and outputting a foundation bearing capacity grade zoning map and a corresponding engineering suggestion map; acquiring the target bearing capacity requirement input by a user, automatically comparing the corrected bearing capacity value of each region, if the target bearing capacity requirement is not satisfied, matching a corresponding processing technology from a preset foundation treatment rule base according to the disturbance level and the soil layer structure parameter of the region, judging whether the target bearing capacity requirement can be satisfied after treatment, and outputting a corresponding construction suitability evaluation result and a foundation treatment suggestion; the construction suitability evaluation result and the foundation treatment suggestion comprise: for a region that does not meet the user's target bearing capacity requirement, constructing a regional stability response vector in combination with the disturbance level and the soil layer structure parameter; inputting the same into the foundation treatment rule base constructed based on rule matching and engineering experience factor weighting, retrieving an applicable processing technology combination scheme, comparing the simulation result of the improved bearing capacity with the target bearing capacity requirement, and judging the technical feasibility; under the condition that the feasibility condition is satisfied, generating the foundation treatment suggestion including the treatment mode, applicable soil layer conditions, construction key points and the expected bearing capacity improvement range, and outputting the construction suitability evaluation result of the corresponding region as an auxiliary judgment basis; spatially superimposing the layers of the foundation bearing capacity grade zoning map, the construction suitability evaluation result and the foundation treatment suggestion, and outputting a visualization layer result that can be used for three-dimensional geological model display.

2. The method for zoning and evaluating the bearing capacity of a coal mining area foundation according to claim 1, characterized in that, the step of dividing the three-dimensional geological model into a number of regions with soil layer structure parameters comprises: constructing regular grid units or irregular three-dimensional grid units in the three-dimensional geological model, extracting the soil layer structure parameters of each unit respectively, and merging adjacent units with a difference of main control soil layer type smaller than a preset threshold into a continuous region; the merging process adopts a clustering rule based on a minimum unit quantity threshold to give consideration to both spatial continuity and engineering discrimination boundaries; the soil layer structure parameter of the region is a weighted average result of the soil layer structure parameters of the units contained therein on the basis of volume weight, and is subjected to fitting expression on a regional scale for subsequent bearing capacity calculation and suitability evaluation.

3. The method for zoning and evaluating the bearing capacity of a coal mining area foundation according to claim 2, characterized in that, the soil layer structure parameters comprise: The types, thicknesses, natural unit weights, void ratios, liquid limits, plasticity indices, compression moduli, internal friction angles, cohesion, foundation saturation, and groundwater depths of different soil layers within each spatial unit; The acquisition of the dominant soil layer type includes: selecting the soil layer with the largest thickness within the spatial unit and continuously distributed within the effective depth range; if the soil layer is a soft and compressible soil layer, then a weighted evaluation is performed based on its compression modulus and void ratio, and the soil layer that plays a dominant role in bearing capacity control is selected as the dominant soil layer type of the unit.

4. The method for zoning and evaluating the bearing capacity of a coal mining area foundation according to claim 1, characterized in that, The construction of the goaf disturbance zone model includes: Based on the regional division of the three-dimensional geological model, and according to the goaf depth, spatial range, roof structure parameters and backfill status in the goaf characteristics of each region, as well as the settlement rate and settlement deformation curve characteristics reflected in the ground settlement monitoring data, the vertical depth and horizontal distribution range of the regional disturbance influence range are determined. Through the contact structure relationship between the goaf area and its overlying soil in the three-dimensional geological model, the regional boundary based on the disturbance influence is reconstructed, and the soil structure parameters are updated to form a continuous goaf disturbance area model. Based on the disturbance response weight model, the disturbance influence of each region after the regional boundary reconstruction is assessed, and the disturbance level is obtained.

5. The method for zoning and evaluating the bearing capacity of a coal mining area foundation according to claim 4, characterized in that, The disturbance response weight model is constructed based on the following parameters: The depth H of the goaf, the horizontal span L of the spatial range, the integrity rate R of the roof rock structure, the compaction degree C of the backfill, the settlement rate V, and the settlement curvature K of each region are extracted. Dimensionless processing is performed on H, L, R, C, V, and K to obtain standardized parameters xH, xL, xR, xC, xV, and xK, where R and C are inversely standardized. Based on historical monitoring data of the preset sample area, the entropy weight method is used to determine the weight wi of each standardized parameter, satisfying Σwi=1. The standardized parameters corresponding to each region are substituted into the disturbance response weight model, and the comprehensive disturbance impact value D is calculated according to D=Σ(wi·xi). Based on the clustering and grading rules, each region is divided into multiple disturbance levels.

6. The method for zoning and evaluating the bearing capacity of a coal mining area foundation according to claim 1, characterized in that, The foundation bearing capacity zoning map and corresponding engineering recommendation map include: The modified bearing capacity value of each region is compared with the preset bearing capacity discrimination threshold. According to the construction bearing capacity requirements, the regions are divided into three categories: construction zone, restricted construction zone, and prohibited construction zone. The construction zone corresponds to the region where the modified bearing capacity value is higher than the upper limit threshold, the restricted construction zone corresponds to the region where the modified bearing capacity value is between the upper and lower limits threshold, and the prohibited construction zone corresponds to the region where the modified bearing capacity value is lower than the lower limit threshold. Based on the regional division, the corresponding foundation bearing capacity level zoning map is generated. Combined with the disturbance level, the main controlling soil layer type and the original bearing capacity value, the engineering suggestion map containing construction restrictions, foundation treatment suggestions and precautions is output.

7. A zoning evaluation system for the bearing capacity of foundations in coal mining areas, characterized in that, The system applies the zoning evaluation method for foundation bearing capacity in coal mining areas as described in any one of claims 1 to 6, including: Geological information acquisition module: Acquires geological information, obtains characteristics of mining subsidence, and constructs a three-dimensional geological model; Disturbance assessment module: Based on the characteristics of mining subsidence, the three-dimensional geological model is divided into several regions with soil structure parameters, and a mining subsidence disturbance zone model is constructed to assess the disturbance level of each region. Bearing capacity calculation module: Based on soil structure parameters, calculate the original bearing capacity value of the foundation in each area, and correct the original bearing capacity according to the corresponding disturbance level to obtain the corrected bearing capacity value of each area; Zoning Module: Divides each area according to the modified bearing capacity value, and outputs a zoning map of foundation bearing capacity level and corresponding engineering suggestion map; Foundation treatment module: It obtains the target bearing capacity requirement input by the user, automatically compares it with the corrected bearing capacity value of each area, and if it does not meet the target bearing capacity requirement, it matches the corresponding treatment technology from the preset foundation treatment rule library according to the disturbance level and soil structure parameters of the area, and judges whether the target bearing capacity requirement can be met after treatment, and outputs the corresponding construction suitability assessment results and foundation treatment suggestions. Visualization module: Spatially overlays the layers of foundation bearing capacity level zoning map, construction suitability assessment results and foundation treatment recommendations, and outputs the visualization layer results that can be used for displaying 3D geological models.

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