Regional tectonic stress risk quantitative analysis method for tunnel engineering

Abstract

The invention relates to the technical field of geological engineering safety risk evaluation, in particular to a regional tectonic stress risk quantitative analysis method for tunnel engineering. The method comprises the following steps: collecting multi-source geomechanical parameters, simulating and inverting a tectonic stress field, and verifying the tectonic stress field; constructing a multi-scale geomechanical model, coupling simulation tectonic stress and gravity stress, and generating a stress space basic layer; utilizing Kriging interpolation and inversion decomposition to obtain a stress value and a directional diagram layer; calculating an included angle between the maximum principal stress direction and the tunnel axis, and performing vector decomposition to obtain a vertical stress component; and carrying out standardized normalization on the factors, determining a weight calculation risk value, and finally generating a tectonic stress risk quantitative grading graph and carrying out GIS visual rendering. The tunnel engineering-oriented risk quantitative analysis mechanism is constructed by retaining the directivity and spatial heterogeneity characteristics of the tectonic stress tensor, and the authenticity, resolution and engineering applicability of tectonic stress identification are remarkably improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of geological engineering safety risk assessment, and particularly relates to a regional tectonic stress risk quantitative analysis method for tunnel engineering. BACKGROUND

[0002] The tectonic stress field refers to the geostress field that causes tectonic movement, generates tectonic strain and forms various tectonic traces, and is generally obtained through focal mechanism solution analysis, key tectonic site in-situ geostress testing (such as hydraulic fracturing method / casing unclamping method / three-dimensional stress tensor ultrasonic measurement method) and numerical simulation inversion analysis. The traditional tectonic stress field analysis follows the "point-domain" progressive reconstruction method, and the geostress discrete point data are obtained through in-situ testing means such as hydraulic fracturing method and casing unclamping method, the regional stress field is reconstructed in combination with physical experiments or numerical inversion, and finally the tectonic stress factor layer is generated and participates in the regional stability evaluation. However, the existing method simplifies the three-dimensional geostress tensor into a scalar, such as the maximum principal stress intensity, which only reflects the stress size and ignores the relationship between the directionality and the engineering axis, resulting in that the anisotropy characteristics of the tectonic stress are systematically compressed, the spatial heterogeneity of the evaluation result is insufficient, and the risk underestimation problems such as tunnel asymmetric damage and rock burst misjudgment are easily caused. SUMMARY

[0003] Therefore, it is necessary to provide a regional tectonic stress risk quantitative analysis method for tunnel engineering to solve at least one of the above technical problems.

[0004] To achieve the above-mentioned purpose, a regional tectonic stress risk quantitative analysis method for tunnel engineering comprises the following steps: Step S1: collecting a multi-source geomechanics parameter data set of a target tunnel engineering region; simulating and inverting a regional tectonic stress field based on the multi-source geomechanics parameter data set, and performing a measured check to obtain a tectonic stress tensor; Step S2: analyzing the spatial scale and geological unit of the target tunnel engineering region, and constructing a regional multi-scale geomechanics simulation model; Step S3: performing numerical coupling simulation on the tectonic stress tensor and the gravity stress tensor based on the regional multi-scale geomechanics simulation model, and performing structured processing on the numerical coupling simulation result to obtain a tectonic stress space basic layer; Step S4: performing Kriging interpolation on the principal stress discrete points in the tectonic stress space basic layer to generate a continuous grid layer; inverting the continuous grid layer and decomposing the inversion result to obtain a stress value layer and a direction layer; Step S5: Calculate the included angle between the maximum principal stress direction and the tunnel axis based on the direction layer and the preset tunnel route trend layer, to obtain an included angle layer; and perform vector decomposition on the stress value layer and the included angle layer, to obtain a vertical principal stress component layer; Step S6: Perform factor standardization and normalization processing on the vertical principal stress component layer, to generate a regional tectonic stress factor evaluation dataset; determine the weight coefficients of each factor based on the regional tectonic stress factor evaluation dataset, and calculate a regional tectonic stress risk value, to obtain a tectonic stress risk quantitative classification layer; perform GIS visual rendering on the tectonic stress risk quantitative classification layer, to output a regional tectonic stress risk distribution map.

[0005] The present application enhances the physical real perception ability of the regional stress state by introducing the inversion and verification mechanism of the tectonic stress tensor, effectively improves the reliability and integrity of the tectonic stress field data; fuses the multi-scale geomechanical modeling system and the coordinate adaptive strategy, so that the model is closer to the spatial scale characteristics of the engineering scene, and the simulation accuracy and boundary adaptability are improved; a structured expression mode of the three-dimensional coupled stress field is constructed, the tensor-level fusion of the tectonic stress and the gravity stress is realized, and the limitation of simplifying the stress field to a scalar representation in the traditional method is broken through; the direction-retained tensor interpolation and spatial decomposition mechanism is adopted, the stress intensity information is retained, and the directional element is introduced to participate in the engineering axis coupling analysis, the spatial relationship difference between the tectonic stress and the tunnel trend is revealed, and the spatial resolution and engineering pertinence of the evaluation result are significantly improved; the vertical principal stress component is extracted through vector decomposition, a quantitative factor highly related to the engineering stability risk is constructed, and the evaluation index is more interpretable and responsive; combined with the normalization processing and the analytic hierarchy process, the multi-dimensional fusion and weight precise distribution of the risk factors are realized, the actual influence of the tectonic stress field on the potential damage mechanism of the tunnel engineering is effectively reflected; and finally, the tectonic stress risk distribution map output has high resolution and high recognition visual expression ability, provides scientific support for the tunnel routing optimization, high-risk section identification and construction risk control, and significantly improves the safety design and fine management level of the tunnel engineering in the geostress environment. BRIEF DESCRIPTION OF DRAWINGS

[0006] Other features, objects, and advantages of the present application will become more apparent from the following detailed description of non-limiting embodiments made with reference to the accompanying drawings: Figure 1 FIG. 1 is a step flowchart of a regional tectonic stress risk quantitative analysis method for a tunnel engineering according to the present application; Figure 2 FIG. 2 is a tectonic stress field analysis technical flowchart in an embodiment of the present application; Figure 3 FIG. 3 is a GIS geostress vector layer decomposition schematic diagram in an embodiment of the present application; Figure 4 Asymmetry breaking process diagram in the embodiment of the present application; Figure 5 The figure is a schematic diagram of the crust stability evaluation method considering the tectonic stress field direction in the embodiment of the present application. DETAILED DESCRIPTION

[0007] The technical method of the present application will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0008] In addition, the accompanying drawings are only schematic diagrams of the present application, and are not necessarily drawn to scale. The same reference signs in the drawings represent the same or similar parts, and thus repeated descriptions thereof will be omitted. Some of the block diagrams shown in the drawings are functional entities, which do not necessarily have to correspond to physically or logically independent entities. The functional entities can be implemented in the form of software, or in one or more hardware modules or integrated circuits, or in different network and / or processor methods and / or microcontroller methods.

[0009] It should be understood that although the terms "first", "second" and the like can be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, without departing from the scope of the exemplary embodiments, a first element can be referred to as a second element, and similarly a second element can be referred to as a first element. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0010] To achieve the above-mentioned purpose, please refer to Figures 1 to 3 The present application provides a regional tectonic stress risk quantitative analysis method for tunnel engineering, which comprises the following steps: Step S1: Collecting a multi-source geomechanical parameter data set of a target tunnel engineering region; simulating and inverting a regional tectonic stress field based on the multi-source geomechanical parameter data set, and performing a measured check to obtain a tectonic stress tensor; Step S2: Analyzing the spatial scale and geological unit of the target tunnel engineering region, and constructing a regional multi-scale geomechanical simulation model; Step S3: Numerically coupling and simulating the tectonic stress tensor and the gravity stress tensor based on the regional multi-scale geomechanical simulation model, and structurally processing the numerical coupling and simulation results to obtain a tectonic stress space basic layer; Step S4: Kriging interpolation is performed on the principal stress discrete points in the tectonic stress space basic layer to generate a continuous grid layer; inversion is performed on the continuous grid layer, and the inversion results are decomposed to obtain a stress value layer and a direction layer; Step S5: Based on the direction layer and a preset tunnel route layer, the included angle between the maximum principal stress direction and the tunnel axis of each grid cell is calculated to obtain an included angle layer; vector decomposition is performed on the stress value layer and the included angle layer to obtain a vertical principal stress component layer; Step S6: Factor standardization and normalization are performed on the vertical principal stress component layer to generate a geostress factor evaluation dataset; the weight coefficients of each factor are determined based on the geostress factor evaluation dataset, and the regional tectonic stress risk value is calculated to obtain a tectonic stress risk quantitative classification layer; GIS visualization rendering is performed on the tectonic stress risk quantitative classification layer to output a regional tectonic stress risk distribution map.

[0011] Preferably, step S1 comprises the following steps: Step S11: Collecting geological structure deformation data, lithology parameters, hydraulic fracturing data, casing release data and GPS monitoring data of the target tunnel engineering region to obtain a multi-source geomechanics parameter dataset; Step S12: Based on the multi-source geomechanics parameter dataset, a physical model is established for the regional tectonic stress evolution process, and stress inversion is performed to obtain a preliminary simulation result of the regional tectonic stress field; Step S13: The preliminary simulation result of the tectonic stress field is verified, and residual error is evaluated to obtain a tectonic stress tensor fitting residual error result; Step S14: Based on the tectonic stress tensor fitting residual error result, the reliability of the regional tectonic stress tensor is evaluated to obtain a tectonic stress tensor.

[0012] In the embodiment of the present application, through systematic collection of tectonic deformation data, lithology parameters, hydraulic fracturing data, casing release data and GPS monitoring data in the target tunnel engineering area, a multi-source geomechanical parameter data set is constructed, wherein the tectonic deformation data needs to cover the fault distribution, fold axial direction and geological structure combination relationship, the lithology parameters include Young's modulus, shear modulus, Poisson's ratio and density and other mechanical properties, the hydraulic fracturing data and casing release data must meet the test procedures in the Specification for Field Test of Geomechanics, and directional drilling layout and staged pressurization scheme are adopted to ensure the accuracy of the calculation of the principal stress direction, and the GPS monitoring data should include the horizontal and vertical displacement rate information for nearly three years, and the spatial registration of the observation points is completed; based on the above multi-source geomechanical parameter data set, the physical modeling of the tectonic stress evolution process is carried out, the stress zoning method is used to divide the three-layer structure of the upper, middle and lower crust, the partition boundary conditions are set according to the block boundary and the main fault distribution, the regional tectonic stress field is solved by the static equilibrium equation set and the stress boundary condition, and the preliminary simulation result is obtained, and the output is the stress field data set in the form of three-dimensional tensor; the preliminary simulation result is compared with the measured stress tensor values obtained by hydraulic fracturing and casing release, the fitting error between the stress tensors of each measuring point is calculated using the Frobenius norm, and the 0.3 times normalized residual is used as the fitting accuracy threshold, and the tectonic stress tensor fitting residual result is output; the stress tensor reliability is evaluated according to the residual result distribution, for the area with fitting residual less than the threshold, the simulated tensor is retained as the effective result, and for the area with residual exceeding the limit, the tensor is corrected by using the local weighted interpolation method, and finally the tectonic stress tensor with complete structure and controllable accuracy is obtained.

[0013] Preferably, step S2 comprises the following steps: Step S21: identifying the spatial scale of the block distribution, latitude and longitude span and proposed route range of the target tunnel engineering area, to obtain a regional scale determination result; Step S22: setting a model coordinate system based on the regional scale determination result, to obtain a regional mechanics model coordinate framework; Step S23: analyzing the geological profile data, fault structure information and upper, middle and lower crust layering information of the target tunnel engineering area based on the regional mechanics model coordinate framework, and structurally modeling the region, to obtain a spatial division model; Step S24: assigning corresponding physical properties to different geological units based on the spatial division model and tectonic stress tensor, and setting velocity constraint boundary conditions, to obtain a regional multi-scale geomechanical simulation model.

[0014] In the embodiment of the present application, the parcel boundary vector data of the target tunnel engineering area and the start and end coordinates of the proposed route are imported into the ArcGIS platform, and the number of parcels, boundary distribution, latitude and longitude span, and projection length of the tunnel route in the area are comprehensively calculated, wherein the latitude and longitude span needs to be accurate to 0.001 If the latitude and longitude span is greater than 1.5 or the engineering route spans multiple first-order structural units, the area is identified as a large-scale engineering area, and the area scale determination result is output for coordinate system selection; the model coordinate system is set according to the area scale determination result, the spherical shell coordinate system is set if the determination result is a large-scale area, the spatial projection conversion is performed with the WGS-84 earth ellipsoid parameters, the plane rectangular coordinate system is set if the determination result is a small-scale area, and the unified Gauss projection zone coordinates are adopted, and finally the area mechanics model coordinate framework for three-dimensional tectonic mechanics analysis is obtained; after determining the coordinate framework, the upper crust (0-15 km), the middle crust (15-30 km), and the lower crust (30-45 km) are divided into three layers by integrating the existing geological digital data, the layered boundary is set based on the seismic tomography and Moho depth data, the tectonic contact surface is constrained by the fault dislocation line and the fold axis surface, the geological unit boundary surface and volume unit are constructed by a three-dimensional modeling tool such as GOCAD, and a complete spatial division model is generated; based on the spatial division model and the tectonic stress tensor data, the mechanical parameters of each geological unit are assigned, wherein the Young's modulus is limited between 10-90 GPa, the shear modulus is limited between 5-45 GPa, the Poisson's ratio is set to 0.20-0.30, the rock density is set to 2.5-2.9 , and the model boundary velocity constraint is set according to the regional plate motion monitoring data, wherein the horizontal velocity of the north-south boundary is set to ±25 mm / a, and the vertical boundary is set to 0 displacement condition, and finally a regional multi-scale geomechanical simulation model satisfying the continuity of structure, coordinate, and physical property is established.

[0015] Preferably, step S3 comprises the following steps: Step S31: tensor synthesis is performed on the tectonic stress tensor and the gravity stress tensor, and physical coupling of the multi-source stress field is performed to obtain a coupled stress tensor field; Step S32: numerical simulation is performed based on the regional multi-scale geomechanical simulation model and the coupled stress tensor field, stress propagation and deformation response are calculated, and a shallow coupled geostress numerical simulation result is obtained; Step S33: residual calculation is performed on the shallow coupled geostress numerical simulation result, stress tensor data is extracted based on the residual calculation result, spatial coding and layer decomposition are performed according to the three-dimensional grid structure, and a tectonic stress spatial basic layer is obtained.

[0016] In the embodiment of the present application, the tectonic stress tensor and the gravity stress tensor are taken as inputs, the point-by-point summation processing of the two tensor fields is performed by using the tensor superposition principle, the gravity stress tensor is calculated according to , wherein is the rock density, is the gravity acceleration (9.81 is the depth, and the density parameter is valued between 2.5-2.9 according to different geological units, the calculation result maintains the spatial structure corresponding to the three-dimensional regional grid, the tensor synthesis adopts the Frobenius inner product form, the stress tensor of each spatial unit is synthesized into six components , , , , , to obtain the coupled stress tensor field; the regional multi-scale geomechanical simulation model is taken as the calculation domain, the coupled stress tensor field is taken as the initial stress field, the explicit difference method is applied to perform the static simulation, the distribution response and deformation influence of the coupled stress in the shallow region (depth 0-1000 m) are calculated, the vertical layering structure of dividing one layer every 100 m is adopted in the simulation process, the stress conduction calculation is performed on each layer node, and multiple groups of indexes including the principal stress, shear stress and volumetric strain are output to form the numerical simulation result of the shallow coupled crustal stress; the simulation output result is compared with the original tectonic stress tensor field point by point, the residual error is calculated by using the Frobenius norm formula, the tensor data with the residual error less than 0.3 is reserved as the effective value, the three-dimensional space grid (horizontal 500 m x 500 m, vertical 100 m) is divided at equal intervals, the tensor is spatially encoded, the field mark , , and the direction angle are marked, and the multi-channel layer structure of each spatial unit is generated by using the raster grid point mapping tool in ArcGIS, and finally the tectonic stress spatial basic layer is output.

[0017] Preferably, step S4 comprises the following steps: Step S41: vector extraction is performed on the principal stress discrete points in the tectonic stress spatial basic layer to obtain a principal stress discrete point data set; Step S42: spatial interpolation is performed on the principal stress size in the principal stress discrete point data set by using the Kriging method to obtain a continuous raster layer of the principal stress value; Step S43: directional interpolation processing is performed on the principal stress direction vector information in the principal stress discrete point data set by using the weighted Kriging interpolation method to obtain a continuous raster layer of the principal stress direction.

[0018] Step S44: Invert and synthesize the continuous raster layer of principal stress values ​​and the continuous raster layer of principal stress directions to obtain the principal stress tensor field layer. Step S45: Based on the tensor principal axis direction information of each grid cell in the principal stress tensor field layer, perform directional decomposition on the tensor field, extract the tensor magnitude component, and obtain the stress value layer and the direction layer.

[0019] In this embodiment of the invention, the vector field extraction tool of the ArcGIS platform is used to process the discrete points of principal stress in the structural stress spatial base layer, and the maximum principal stress in the tensor field is called ( The three-dimensional direction vector components of ) , , Based on the principal stress magnitude values, a discrete principal stress point dataset is constructed using the spatial coordinates of each point. This dataset includes the principal tensor values ​​and their corresponding direction information. Based on the stress magnitude field in the discrete principal stress point dataset, ordinary kriging in the Geostatistical Analyst module is used for spatial interpolation calculation. The search neighborhood radius is set to 1500 m, the minimum number of neighbors is 10, and the interpolation range covers the tunnel line control area plus a boundary buffer of 1000 m. A continuous raster layer of principal stress values ​​is output, with a raster cell size of 100 m × 100 m. The principal stress direction information is interpolated by first normalizing each principal stress direction vector to a unit vector, and then interpolating the three direction components (…). , , Weighted kriging interpolation was performed separately, with the weighting factor set according to the tensor magnitude. Geostatistical Analyst's multivariate joint interpolation tool was used to generate continuous raster layers for the three directional components. Then, in each raster cell, the directional field was restored to the complete principal stress direction vector through 3D vector synthesis, forming a continuous raster layer for the principal stress directions. The continuous raster layer for principal stress values ​​and the continuous raster layer for principal stress directions were then inverted and synthesized point-by-point, based on... The three components of the value and direction vectors are recovered within each grid cell. The spatial distribution of the tensor yields the principal stress tensor field layer, which is saved as multi-band floating-point raster data containing the magnitude and direction of the principal stresses. Using the principal stress tensor field layer as input, the principal axis direction information of each raster cell is extracted, the tensor vector magnitude is calculated, and the inverse cosine solution of the principal axis direction is performed to extract the maximum principal stress value as the stress value layer. At the same time, the principal axis direction angles (tilt and azimuth) are extracted to construct the direction layer, ultimately forming the stress value layer and direction layer for geostress direction analysis and engineering axis coupling calculation.

[0020] Preferably, step S5 includes the following steps: The step S5 includes the following steps: The direction layer is subjected to coordinate vector extraction, and the extraction result is standardized to a principal stress direction angle layer within [0°~360°]; The preset tunnel route direction layer is subjected to vectorization processing, and a route direction value of each grid position is extracted according to the tunnel axis direction to obtain a route direction angle layer; The direction difference of each grid unit is calculated based on the principal stress direction angle layer and the route direction angle layer to obtain an included angle layer of the maximum principal stress direction and the route direction.

[0021] In the embodiment of the present application, first, the direction layer is subjected to coordinate vector extraction, and the extraction method is based on the construction of a horizontal projection vector in a two-dimensional plane according to the three-dimensional components of the principal stress direction , The Field Calculator tool in ArcGIS is called to calculate the azimuth angle of the direction vector in each grid relative to the north direction , and then the Raster Calculator module is used to uniformly convert the negative value to a standard direction angle within 0°~360° to generate a principal stress direction angle layer; second, the preset tunnel route direction layer is subjected to vectorization processing, first, the route layer is interrupted and segmented at an interval of 100 m, the start point and end point coordinates of each segment are extracted, and the direction vector in the horizontal plane is calculated, then the direction of each segment relative to the north direction is calculated , the Join Field tool is used to assign the value to each grid unit spatially overlapped with the value to generate a route direction angle layer, and the output value range is limited within 0°~180°; finally, the direction difference of the two angle layers is calculated based on the Map Algebra expression in ArcGIS, the formula is , if is greater than 90°, it is replaced by 180° - to ensure that the included angle is always within the range of 0°~90°, and finally the included angle layer is output as the basic data for the geometric relationship analysis of the ground stress direction and the tunnel direction.

[0022] Preferably, the step S5 includes the following steps: The included angle layer is subjected to sine value conversion processing to obtain a direction included angle sine layer; The stress value layer is subjected to standardization processing to convert the original principal stress value to a vector module length form to obtain a standard principal stress module length layer; Based on the standard principal stress modulus layer and the sine wave of the direction angle layer, the principal stress vector is decomposed in direction, and the stress vector component layer perpendicular to the tunnel alignment is extracted and recorded as the vertical principal stress component map.

[0023] In this embodiment of the invention, firstly, the included angle layer is subjected to sine value transformation. The Raster Calculator tool is called in the ArcGIS platform to convert the angle value of each raster cell in the included angle layer to a sinusoidal value. Convert the units to radians. and apply the expression First, a sine value layer of the included angle is obtained, with the value range limited to 0 to 1, used to characterize the proportion of orthogonal components between the principal stress direction and the tunnel orientation. Second, the maximum principal stress value layer is standardized, assuming the original stress value range is... to (in , Using the linear normalization formula The original principal stress values ​​were standardized to a dimensionless principal stress modulus layer between 0 and 1, and a Reclassify tool was used to ensure that all outliers or null values ​​were removed or filled to eliminate the influence of boundary disturbances on subsequent decomposition calculations. Finally, grid-by-grid multiplication was performed based on the standard principal stress modulus layer and the sine angle layer, using an expression... This yields the vertical principal stress component layer.

[0024] Preferably, step S6, which involves factor standardization and normalization of the vertical principal stress component layer, includes: Spatial reclassification is performed on the vertical principal stress component layer to divide continuous values ​​into set level intervals, thus obtaining the vertical principal stress level layer. Acquire lithological type layers, tunnel depth data, regional fault distribution layers, and regional topographic data for the target tunnel engineering area; The engineering response coefficients of different lithological categories in the lithological type layer are extracted and encoded to obtain the lithological response factor layer; Extract the tunnel axis depth information from the regional topographic data and perform spatial interpolation in combination with the tunnel burial depth data to obtain the burial depth factor layer; Buffer analysis was performed on the regional fault distribution layer to identify risk zones adjacent to faults and obtain a tectonic activity zone factor layer. The included angle layer is subjected to discrete hierarchical processing, and the control levels are divided according to the results of the discrete hierarchical processing to obtain the included angle control factor layer. The vertical principal stress grade layer, the lithology response factor layer, the buried depth factor layer, the tectonic activity zone factor layer and the angle control factor layer are linearly standardized to obtain a ground stress factor evaluation data set.

[0025] In the embodiment of the application, first, the Reclassify tool of ArcGIS is used to perform spatial reclassification processing on the vertical principal stress component layer, and the numerical range is divided into five grade intervals, such as 0-0.2, 0.2-0.4, 0.4-0.6, 0.6-0.8 and 0.8-1.0, according to the engineering experience threshold value, and grade codes 1 to 5 are assigned, a vertical principal stress grade layer is output, and the relative strength of the principal controlling lateral stress level in different regions is reflected; second, four types of spatial factor layers of the lithology type layer of the target tunnel engineering region, the tunnel buried depth data, the regional fault distribution layer and the regional terrain data are obtained, the lithology type layer is derived from the 1:50000 geological map digitization data, the Field Calculator is called to assign coding to the lithology field, for example, hard rock (such as granite and diabase) is assigned a value of 1, medium-hard rock (such as limestone and sandstone) is assigned a value of 2, and soft rock (such as shale and mudstone) is assigned a value of 3, and a lithology response grade table is established in combination with the existing rock elastic modulus and shear modulus test results to generate a lithology response factor layer; the Topo to Raster method is used to perform spatial interpolation on the tunnel buried depth data to generate a terrain continuous surface, the Extract by Mask tool in ArcGIS Spatial Analyst is used to extract the difference between the minimum elevation of the tunnel axis on the terrain surface and the design buried depth data, and a buried depth factor layer is output, with a value range of 50 m to 800 m; buffer analysis is performed on the regional fault distribution layer, the first-order fault buffer width is set to 1000 m and the second-order fault buffer width is set to 500 m according to the fault activity grade, and a tectonic adjacent area is extracted by superposition to generate a tectonic activity zone factor layer; the angle layer obtained in the previous step is discretely graded according to the range of 0°-90°, divided into five angle grade categories of 0-15°, 15-30°, 30-45°, 45-60° and 60-90°, and assigned with control grades 1 to 5, and an angle control factor layer is output; finally, the value ranges of the above five types of factor layers are uniformly converted to dimensionless data of 0 to 1 by applying linear standardization methods, and the Raster Calculator is used to perform standardization calculation on each layer separately, and finally a ground stress factor evaluation data set composed of the vertical principal stress grade layer, the lithology response factor layer, the buried depth factor layer, the tectonic activity zone factor layer and the angle control factor layer is formed.

[0026] ​Preferably, the weight coefficients of each factor are determined based on the evaluation data set of the ground stress factor in step S6, and the regional tectonic stress risk value is calculated, comprising: The weight influence factor scoring is performed on each factor layer in the ground stress factor evaluation data set, a pair comparison matrix is constructed, and an analytic hierarchy process input matrix is obtained; The characteristic roots and characteristic vectors of each risk factor are calculated based on the analytic hierarchy process input matrix, whether the consistency ratio meets the set threshold value is judged, and a weight coefficient set is obtained; The ground stress factor evaluation data set and the weight coefficient set are weighted and superimposed, and a regional tectonic stress risk index grid layer is constructed; The tectonic stress risk index grid layer is reclassified, the interval is divided according to the preset risk level division standard, and a tectonic stress risk quantitative classification layer is obtained.

[0027] In the embodiment of the application, first, the weight influence factor scoring is performed on each factor layer in the ground stress factor evaluation data set, the expert scoring weight is set for five layers, i.e., the vertical principal stress level layer, the lithology response factor layer, the burial depth factor layer, the tectonic activity zone factor layer and the angle control factor layer, according to the influence degree of engineering mechanics, the scoring value represents the relative importance between factors in the pair ratio system of 1 to 9, a 5x5 pair comparison matrix is constructed, the diagonal elements in the matrix are 1, and the reciprocal elements are the reciprocal, which is used as the input matrix of the analytic hierarchy process; secondly, the maximum characteristic root of the matrix is calculated by using the characteristic root method , and the corresponding characteristic vector is extracted, wherein each represents the normalized weight coefficient of the corresponding factor, and the consistency ratio is used for consistency test, , RI is taken from the Saaty consistency random index table, when CR 0.1, the matrix consistency is determined to pass, and the weight coefficient set is output; then, each layer in the ground stress factor evaluation data set is weighted and superimposed pixel by pixel according to the corresponding weight by using the Raster Calculator tool of ArcGIS, a regional tectonic stress risk index grid layer is generated, and the layer value range is limited to 0 to 1; finally, the tectonic stress risk index grid layer is reclassified, the threshold interval is divided according to the preset five-level risk level standard, the classification interval is set as [0-0.2), [0.2-0.4), [0.4-0.6), [0.6-0.8), [0.8-1.0] according to experience, and the level identification 1 to 5 is given, which respectively corresponds to the low risk area, the lower risk area, the medium risk area, the higher risk area and the high risk area, and the tectonic stress risk quantitative classification layer is output.

[0028] Preferably, the GIS visual rendering of the tectonic stress risk quantitatively graded layer in step S6 comprises: Color mapping is performed on the tectonic stress risk quantitatively graded layer, a graded color scale is configured for different risk levels, and a rendered tectonic stress risk layer is obtained; A legend is generated and a map is decorated for the rendered tectonic stress risk layer, and a tectonic stress risk visual map sketch is obtained. A high-risk area is extracted from the tectonic stress risk distribution map, typical stress mutation zones and tectonic active segments are marked, and a regional tectonic stress risk distribution map is obtained.

[0029] In the embodiment of the present application, first, the tectonic stress risk quantitatively graded layer is opened in the ArcGIS platform, the Symbology module is called to perform color mapping on the layer, and the layer is rendered according to the risk level field assigned in the graded layer, a five-level color scale scheme is set, wherein the low-risk area is assigned a light green color, the lower-risk area is assigned a yellow color, the medium-risk area is assigned an orange color, the higher-risk area is assigned a red color, and the high-risk area is assigned a dark red color, to ensure that the color contrast is clear and continuous, and the rendered tectonic stress risk layer is output, and the graded field is bound in the layer attribute to ensure dynamic linkage of the map; second, the Layout View function is used to decorate the map of the rendered layer, a compass, a scale, a latitude and longitude grid, a legend box and a title are added to the drawing, the legend is composed of a graded color band and corresponding level text description, the legend position is set to be fixed at the lower right corner of the drawing in the Legend Properties, the map border line width is set to 0.5 pt, and the map title is uniformly named as a regional tectonic stress risk visual map, and a tectonic stress risk visual map sketch is output; and finally, the map is subjected to spatial analysis processing, the Raster Calculator is called to extract high-risk raster cells with a graded value of 4 and 5, the Region Group tool is used to identify continuous areas, and the Zonal Statistics is used to calculate the boundary value variation range of the areas, the boundary paragraphs with a gradient change rate greater than 0.4 are extracted as typical stress mutation zones, the fault layer loaded in step S21 is combined, the spatial overlap area of the high-risk area and the fault active zone is identified by the Intersect tool, and text annotation is performed, and finally, a regional tectonic stress risk distribution map containing risk grading, typical mutation zone and tectonic active segment annotation information is generated.

[0030] Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting, the scope of the present application is not limited by the above description, and therefore all changes falling within the meaning and scope of the equivalent elements of the application file are intended to be included in the present application.

[0031] The foregoing is considered as illustrative only of the principles of the application. Numerous modifications and changes will readily occur to those skilled in the art, and it is intended to embrace all such modifications and changes that fall within the scope of the application. Accordingly, the application is not to be restricted in scope to the specific embodiments disclosed herein but is to be accorded the full scope that the principles and novel features request appropriately granted.

Claims

1. A quantitative analysis method for regional tectonic stress risk in tunnel engineering, characterized in that, Includes the following steps: Step S1: Collect multi-source geomechanical parameter datasets for the target tunnel engineering area; The regional tectonic stress field was simulated and inverted based on a multi-source geomechanical parameter dataset, and the result was verified by field measurements to obtain the tectonic stress tensor. Step S2: Analyze the spatial scale and geological units of the target tunnel engineering area, and construct a multi-scale geomechanical simulation model of the region; Step S3: Based on the regional multi-scale geomechanical simulation model, numerical coupling simulation of tectonic stress tensor and gravity stress tensor is performed, and the numerical coupling simulation results are structured to obtain the basic spatial layer of tectonic stress. Step S4: Perform Kriging interpolation on the principal stress discrete points in the structural stress space base layer to generate a continuous raster layer; Invert the continuous raster layer and decompose the inversion results to obtain the stress value layer and the orientation layer; Step S5: Calculate the angle between the direction of the maximum principal stress and the tunnel axis for each grid cell based on the direction layer and the preset proposed tunnel route layer to obtain the angle layer; perform vector decomposition on the stress value layer and the angle layer to obtain the vertical principal stress component layer. Step S6: Perform factor standardization and normalization on the vertical principal stress component layer to generate a geostress factor evaluation dataset; The weight coefficients of each factor are determined based on the geostress factor evaluation dataset, and the regional tectonic stress risk value is calculated to obtain a quantitative classification layer of tectonic stress risk. The GIS visualization rendering of the quantitative classification layer of tectonic stress risk is used to output a regional tectonic stress risk distribution map.

2. The method for quantitative analysis of regional tectonic stress risk in tunnel engineering according to claim 1, characterized in that, Step S1 includes the following steps: Step S11: Collect geological structural deformation data, lithological parameters, hydraulic fracturing data, core removal data, and GPS monitoring data of the target tunnel engineering area to obtain a multi-source geomechanical parameter dataset; Step S12: Based on the multi-source geomechanical parameter dataset, perform physical modeling of the regional tectonic stress evolution process and stress inversion to obtain preliminary simulation results of the regional tectonic stress field; Step S13: Verify the preliminary simulation results of the tectonic stress field and perform residual evaluation to obtain the fitting residual results of the tectonic stress tensor; Step S14: Evaluate the reliability of the regional tectonic stress tensor based on the fitting residual results of the tectonic stress tensor, and obtain the tectonic stress tensor.

3. The method for quantitative analysis of regional tectonic stress risk in tunnel engineering according to claim 1, characterized in that, Step S2 includes the following steps: Step S21: Spatial scale identification is performed on the land parcel distribution, latitude and longitude span, and proposed route range of the target tunnel project area to obtain the regional scale determination result; Step S22: Based on the regional scale determination results, set the model coordinate system to obtain the coordinate framework of the regional mechanical model; Step S23: Based on the coordinate frame of the regional mechanical model, analyze the geological profile data, fault structure information and upper, middle and lower crustal layering information of the target tunnel engineering area, and perform structural modeling of the area to obtain a spatial division model; Step S24: Based on the spatial partitioning model and tectonic stress tensor, assign corresponding physical properties to different geological units and set velocity constraint boundary conditions to obtain a regional multi-scale geomechanical simulation model.

4. The method for quantitative analysis of regional tectonic stress risk in tunnel engineering according to claim 1, characterized in that, Step S3 includes the following steps: Step S31: Perform tensor synthesis on the tectonic stress tensor and the gravitational stress tensor, and perform physical coupling of the multi-source stress fields to obtain the coupled stress tensor field. Step S32: Numerical simulation is performed based on the regional multi-scale geomechanical simulation model and the coupled stress tensor field to calculate stress propagation and deformation response, and obtain the numerical simulation results of shallow coupled geostress. Step S33: Perform residual calculation on the numerical simulation results of shallow coupled geostress, extract stress tensor data based on the residual calculation results, perform spatial encoding and layer decomposition according to the three-dimensional mesh structure, and obtain the basic layer of the structural stress space.

5. The method for quantitative analysis of regional tectonic stress risk in tunnel engineering according to claim 1, characterized in that, Step S4 includes the following steps: Step S41: Extract vectors from the principal stress discrete points in the basic layer of the constructed stress space to obtain the principal stress discrete point dataset; Step S42: Use the Kriging method to spatially interpolate the principal stress magnitudes in the principal stress discrete point dataset to obtain a continuous raster layer of principal stress values. Step S43: Use weighted kriging interpolation to perform direction interpolation on the principal stress direction vector information in the principal stress discrete point dataset to obtain a continuous raster layer of principal stress directions; Step S44: Invert and synthesize the continuous raster layer of principal stress values ​​and the continuous raster layer of principal stress directions to obtain the principal stress tensor field layer. Step S45: Based on the tensor principal axis direction information of each grid cell in the principal stress tensor field layer, perform directional decomposition on the tensor field, extract the tensor magnitude component, and obtain the stress value layer and the direction layer.

6. The method for quantitative analysis of regional tectonic stress risk in tunnel engineering according to claim 1, characterized in that, In step S5, the angle between the direction of the maximum principal stress and the tunnel axis is calculated for each grid cell based on the direction layer and the preset proposed tunnel alignment layer. Coordinate vectors are extracted from the direction layer, and the extracted results are standardized into principal stress direction angle layers within the range of [0°~360°]. The preset proposed tunnel route alignment layer is vectorized, and the route direction value of each grid position is extracted according to the tunnel axis direction to obtain the route alignment angle layer. Based on the principal stress direction angle layer and the line direction angle layer, the direction difference is calculated for each grid cell to obtain the angle layer between the maximum principal stress direction and the line direction.

7. The method for quantitative analysis of regional tectonic stress risk in tunnel engineering according to claim 1, characterized in that, Step S5 involves vector decomposition of the maximum principal stress value layer and the included angle layer, including: Perform a sine value conversion on the included angle layer to obtain a sine direction angle layer; The stress value layer is standardized to convert the original principal stress values ​​into vector modulus form, resulting in a standard principal stress modulus layer. Based on the standard principal stress modulus layer and the sine wave of the direction angle layer, the principal stress vector is decomposed in direction, and the stress vector component layer perpendicular to the tunnel alignment is extracted and recorded as the vertical principal stress component map.

8. The method for quantitative analysis of regional tectonic stress risk in tunnel engineering according to claim 1, characterized in that, Step S6 involves factor normalization and standardization of the vertical principal stress component layer, including: Spatial reclassification is performed on the vertical principal stress component layer to divide continuous values ​​into set level intervals, thus obtaining the vertical principal stress level layer. Acquire lithological type layers, tunnel depth data, regional fault distribution layers, and regional topographic data for the target tunnel engineering area; The engineering response coefficients of different lithological categories in the lithological type layer are extracted and encoded to obtain the lithological response factor layer; Extract the tunnel axis depth information from the regional topographic data and perform spatial interpolation in combination with the tunnel burial depth data to obtain the burial depth factor layer; Buffer analysis was performed on the regional fault distribution layer to identify risk zones adjacent to faults and obtain a tectonic activity zone factor layer. The included angle layer is subjected to discrete hierarchical processing, and the control levels are divided according to the results of the discrete hierarchical processing to obtain the included angle control factor layer. Based on the vertical principal stress level layer, lithological response factor layer, burial depth factor layer, tectonic activity zone factor layer, and angle control factor layer, the values ​​of each layer are linearly standardized to obtain the geostress factor evaluation dataset.

9. The method for quantitative analysis of regional tectonic stress risk in tunnel engineering according to claim 1, characterized in that, Step S6 involves determining the weight coefficients of each factor based on the geostress factor evaluation dataset and calculating the regional tectonic stress risk value, including: Weighted influence factor scoring is performed on each factor layer in the geostress factor evaluation dataset, and a pairwise comparison matrix is ​​constructed to obtain the analytic hierarchy process input matrix. Based on the analytic hierarchy process, the eigenvalues ​​and eigenvectors of each risk factor are calculated from the input matrix. The consistency ratio is then determined to meet the set threshold, and a set of weight coefficients is obtained. A regional tectonic stress risk index raster layer is constructed by weighted superposition calculation of the geostress factor evaluation dataset and the weight coefficient set. The tectonic stress risk index raster layer is reclassified and divided into intervals according to the preset risk level classification standard to obtain a quantitative classification layer of tectonic stress risk.

10. The method for quantitative analysis of regional tectonic stress risk in tunnel engineering according to claim 1, characterized in that, Step S6 involves GIS visualization rendering of the quantitative grading layer for structural stress risk, including: Apply color mapping settings to the quantitative classification layer of structural stress risk, configure graded color levels for different risk levels, and obtain the rendered structural stress risk layer. Legends are generated and map sheets are embellished on the rendered structural stress risk layer to obtain a draft of a structural stress risk visualization map. High-risk areas are extracted from the tectonic stress risk distribution map, and typical stress abrupt change areas and tectonic active segments are marked to obtain the regional tectonic stress risk distribution map.

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