Deep fractured rock mass stability numerical simulation analysis method and system

Abstract

The invention discloses a deep fractured rock mass stability numerical simulation analysis method and system, and relates to the technical field of deep underground engineering, and the method comprises the steps: obtaining the distribution characteristics of a deep fractured rock mass based on full-scale and internal scanning; based on deep fractured rock mass distribution characteristics, a three-dimensional fracture space distribution model is established, and a rock sample containing a three-dimensional fracture network is obtained through 3D printing; performing an indoor test by using the rock sample to obtain a mechanical parameter change rule of the fractured rock under different sizes; determining equivalent mechanical parameters of the rock mass characterization unit body and corresponding DEM particle micromechanical parameters by comparing the mechanical parameter variable coefficient with the difference value ratio; determining an excavation disturbance area range; and establishing a continuous-discontinuous region rock mass model based on the excavation disturbance region range to perform tunnel excavation simulation. According to the method, the engineering scale calculation efficiency is improved, and the problem of surrounding rock multi-physics field distortion caused by scale splitting in a traditional method is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of deep underground engineering, and particularly relates to a deep fissure rock mass stability numerical simulation analysis method and system. BACKGROUND

[0002] For deep fissure surrounding rock engineering analysis, the traditional numerical simulation method usually simplifies the rock mass into continuous medium or discrete particle assembly, the former cannot capture the progressive failure process caused by stress concentration due to ignoring the microstructure of fissures, and the latter is difficult to realize engineering scale numerical simulation due to the limitation of calculation scale. In addition, for fissure distribution simulation in fissured rock mass, the fissure is reconstructed based on local limited data on site combined with probability distribution function (uniform distribution, weibull distribution, negative exponential distribution, etc.), which is too idealized and difficult to reflect the actual three-dimensional fissure network distribution characteristics on site. In addition, the fissure parameter values are usually obtained in a weakened manner, and the parameter values lack scientificity.

[0003] To solve the above problems, a rock mass engineering cross-scale simulation calculation method based on REV full-area coverage is disclosed in the prior art. First, a finite element body is modeled for the numerical model, then the damaged elements are deleted for discrete element calculation, and then the rock mass engineering cross-scale simulation calculation is realized. However, this method does not consider the fissure distribution characteristics on site, is limited to ideal conditions, and cannot reflect the actual situation on site. In addition, this method deletes the damaged elements for discrete element calculation, which causes loss of data conversion accuracy and non-conservation of physical quantities, affecting the numerical simulation accuracy. SUMMARY

[0004] In view of the deficiencies in the prior art, the purpose of the present application is to provide a deep fissure rock mass stability numerical simulation analysis method and system, which can obtain full-scale data of deep fissure network and improve the engineering scale calculation efficiency, and solve the problem of distortion of surrounding rock multi-physical field caused by scale fragmentation in the traditional method.

[0005] To achieve the above purpose, the present application is realized by the following technical scheme: In a first aspect, an embodiment of the present application provides a deep fissure rock mass stability numerical simulation analysis method, comprising: Based on full-scale and internal scanning, the distribution characteristics of deep fissure rock mass are obtained; Based on the distribution characteristics of deep fissure rock mass, a three-dimensional fissure spatial distribution model is established, and a rock sample containing a three-dimensional fissure network is 3D printed; The rock sample is used for indoor test to obtain the variation law of mechanical parameters of fissured rock mass under different sizes; the equivalent mechanical parameters of rock mass representation unit and the corresponding DEM particle micro-mechanical parameters are determined by comparing the variation coefficient and difference ratio of mechanical parameters; The range of the excavation disturbed zone is obtained by the engineering analogy method and the theoretical analysis method, and the larger range is taken as the range of the excavation disturbed zone; A continuous-discontinuous regional rock mass model is established based on the range of the excavation disturbed zone to simulate the tunnel excavation.

[0006] As a further implementation, the surface of the deep fractured rock mass is scanned by a three-dimensional laser scanner to obtain the overall surrounding rock fracture distribution characteristics; the surrounding rock fractures in the key area are identified by the photogrammetry method to obtain the surrounding rock fracture distribution characteristics in the key area; and the local surrounding rock fractures are measured by the window measurement method to obtain the local surrounding rock fracture distribution characteristics. The overall surrounding rock fracture distribution characteristics, the key area surrounding rock fracture distribution characteristics, and the local surrounding rock fracture distribution characteristics are normalized and fused to obtain the deep fractured rock mass surface distribution characteristics.

[0007] As a further implementation, the three-dimensional laser scanning result is taken as a background framework by a weighted fusion method, and the measurement results of the photogrammetry method and the window measurement method are taken as supplements.

[0008] As a further implementation, in the key area, the Voronoi diagram method is used to arrange the drill holes to obtain the 360° fracture distribution image of the hole wall, quantitatively extract the fracture parameters, and spatially superimpose the fracture parameters of different drill holes to form a three-dimensional fracture point cloud database.

[0009] As a further implementation, for the fracture parameter distribution characteristics, the drill hole data is taken as the main variable and the surface data is taken as the auxiliary variable for interpolation to obtain the three-dimensional fracture spatial characteristic parameters.

[0010] As a further implementation, based on the three-dimensional fracture network distribution characteristics, the deep rock mass three-dimensional fracture spatial distribution model is reconstructed and restored by combining the C4D software, and the test rock mass model is formed according to the demarcated size, and then the rock sample containing the three-dimensional fracture network is obtained by using the 3D printing technology.

[0011] As a further implementation, the establishment process of the continuous-discontinuous regional rock mass model includes: First, a three-dimensional numerical model is established, and the DEM particle method is used for modeling in the range of the excavation disturbed zone near the tunnel, and the FDM method is used for modeling in the other far-field region; The macroscopic unit cell mechanical parameters and their corresponding particle micro-mechanical parameters are respectively assigned to the FEM grid in the far-field region and the DEM particles in the excavation disturbed range near the tunnel; An overlapping coupling method is used for information transmission calculation, and a hyperbolic function is used in the overlapping coupling region of FDM and DEM to smoothly transition the energy between the two regions.

[0012] In a second aspect, the embodiments of the present application also provide a deep fissure rock mass stability numerical simulation analysis system, comprising: A rock mass distribution characteristic acquisition module is configured to acquire deep fissure rock mass distribution characteristics based on full-scale and internal scanning. A rock sample printing module is configured to establish a three-dimensional fissure spatial distribution model based on the deep fissure rock mass distribution characteristics, and print out a rock sample containing a three-dimensional fissure network through 3D printing. A micro-mechanical parameter determination module is configured to perform indoor tests by using the rock sample to obtain the variation law of the mechanical parameters of the fissure-containing rock mass under different sizes, and determine the equivalent mechanical parameters of the rock mass representation unit and the corresponding DEM particle micro-mechanical parameters by comparing the variation coefficient and the difference ratio of the mechanical parameters. An excavation disturbed zone range determination module is configured to compare the excavation disturbed zone ranges obtained through the engineering analogy method and the theoretical analysis method, and take the larger range as the excavation disturbed zone range. A rock mass model construction module is configured to establish a continuous-discontinuous area rock mass model based on the excavation disturbed zone range to simulate tunnel excavation.

[0013] In a third aspect, the embodiments of the present application also provide an electronic device, comprising a memory and a processor, and computer instructions stored in the memory and running on the processor, when the computer instructions are run by the processor, the steps of the deep fissure rock mass stability numerical simulation analysis method are completed.

[0014] In a fourth aspect, the embodiments of the present application also provide a computer readable storage medium for storing computer instructions, when the computer instructions are executed by the processor, the steps of the deep fissure rock mass stability numerical simulation analysis method are completed.

[0015] The present application has the following advantages: The present application adopts a multi-scale collaborative observation method to realize full-scale data fusion of deep fissure networks, solves the problem of insufficient spatial coverage of traditional single means, and at the same time, the spatial correlation of surface fissures and deep fissures is included in the reconstruction of the three-dimensional fissure model, realizing the reconstruction of the three-dimensional fissure network from the surface to the inside, which helps to build a more accurate and comprehensive fissure model. The present application constructs a multi-size three-dimensional fissure network rock mass model based on 3D printing technology, accurately restores the geometric topological characteristics of natural fissures, breaks through the limitations of traditional prefabricated specimens and numerical simulation that cannot reproduce complex fissure morphology, and obtains the geometric parameters and equivalent mechanical parameters of the deep fissure rock mass representation unit through multi-scale representation unit mechanical tests, thereby providing a basis for the parameter selection of deep fissure rock mass. The application is based on the comprehensive determination of the deep fractured rock mass engineering excavation disturbance range by the engineering analogy method and the theoretical analysis method, the far field unexcavated disturbance area and the nearby excavation disturbance area of the deep fractured rock mass engineering are respectively constructed by the FDM grid and the DEM particle method, and the engineering scale calculation efficiency is improved; meanwhile, the interface coupling information transmission algorithm is introduced, and the problem of distortion of the surrounding rock multi-physical field caused by the scale fragmentation in the traditional method is solved. BRIEF DESCRIPTION OF DRAWINGS

[0016] The drawings accompanying the specification of this application form a part thereof, serve to provide further understanding of the application, and together with the description of the exemplary embodiments of the application, explain the application, and do not limit the application.

[0017] Figure 1 is a flowchart according to one or more embodiments of the application; Figure 2 is a schematic diagram of a 3D printed fracture model according to one or more embodiments of the application; Figure 3 is a schematic diagram of the variation of the geometric and mechanical parameters of a representative element according to one or more embodiments of the application; wherein (a) represents a graph of the variation of Young's modulus with model height, (b) represents a graph of the variation of the internal friction angle with model height, (c) represents a graph of the variation of the cohesive force with model height, (d) represents a graph of the variation of the compressive strength with model height, and (e) represents a graph of the variation of the Poisson's ratio with model height; Figure 4 is a schematic diagram of FDM-DEM coupling simulation according to one or more embodiments of the application. DETAILED DESCRIPTION

[0018] It should be noted that the following detailed description is illustrative only and is intended to provide further description of the application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0019] Example 1 The present embodiment provides a numerical simulation analysis method for the stability of deep fractured rock mass, comprising: Based on full-scale and internal scanning, the distribution characteristics of deep fractured rock mass are obtained; Based on the distribution characteristics of deep fractured rock mass, a three-dimensional fracture spatial distribution model is established, and a rock sample containing a three-dimensional fracture network is 3D printed; The rock sample is used for indoor test, and the variation law of the mechanical parameters of the fractured rock mass under different sizes is obtained; by comparing the variation coefficient and the difference ratio of the mechanical parameters, the equivalent mechanical parameters of the rock mass representation unit and the corresponding DEM particle micro-mechanical parameters are determined; The range of the excavation disturbed zone is obtained by the engineering analogy method and the theoretical analysis method, and the larger range is taken as the range of the excavation disturbed zone. A continuous-discontinuous regional rock mass model is established based on the range of the excavation disturbed zone to simulate the tunnel excavation.

[0020] Specifically, as shown in the figure, the method comprises the following steps: Figure 1 Step 1: Detection of the distribution characteristics of the deep underground engineering fractured rock mass.

[0021] Step 1.1: Multi-scale cooperative detection of the deep fractured rock mass.

[0022] For the deep underground engineering surrounding rock fissure, a multi-scale cooperative observation method of “three-dimensional laser scanning + photogrammetry + window measurement method” is adopted to comprehensively and finely statistically analyze the distribution characteristics of the surrounding rock fissure from macro to micro.

[0023] The three-dimensional laser scanning device is used to scan the surface of the deep fractured rock mass in a large range to obtain the overall surrounding rock fissure distribution characteristics, including width, depth, area, etc. Secondly, the photogrammetry method is used to identify the surrounding rock fissure in a small range of key areas to obtain the fissure tendency, inclination, trace length, etc. Then, the window measurement method is used to measure the local surrounding rock fissure. Finally, the obtained surrounding rock fissure distribution information is normalized and fused to obtain the overall distribution characteristics of the deep fractured rock mass surface.

[0024] In this embodiment, the three-dimensional laser scanning device is an existing three-dimensional laser scanner; the photogrammetry method is a technology for reconstructing the three-dimensional spatial position and form of an object through multi-angle images. Its essence is to extract three-dimensional geometric information from two-dimensional images by using optical projection principle combined with computer algorithm; the window measurement method is a method for obtaining accurate data by measuring the related dimensions of a window to provide basis for subsequent design, installation or modification.

[0025] Among them, the stress concentration area, the intersection area of the structural plane and the significant area of the excavation disturbance are taken as the key areas; for the local surrounding rock with high fissure density or complex geometric characteristics, the window measurement method is used to obtain detailed parameters such as fissure trend, spacing, length and inclination.

[0026] Further, the fissure parameters obtained at different scales are standardized (such as scaling the length, spacing and other parameters to a unified dimension, and projecting the fissure direction to the polar stereographic map), and the weighted fusion method is used to take the three-dimensional laser scanning result as the background framework, and the photogrammetry method and the window measurement method as the detailed supplement, to realize the normalized fusion of the fissure distribution information, so as to obtain the deep fractured rock mass surface distribution characteristics with wide coverage and high precision.

[0027] ​The basic weight is assigned according to the spatial coverage and accuracy of the data source, and the weight is dynamically adjusted in combination with the crack characteristics (such as width, strike). The point cloud data of photogrammetry and window measurement is registered to the three-dimensional laser scanning coordinate system through the ICP (iterative closest point) algorithm to eliminate system errors; the crack width, length and other parameters are standardized (such as normalized to the interval [0, 1]) to avoid the influence of dimension difference on the fusion result.

[0028] Step 1.2: Digital borehole detection of deep fissured rock mass.

[0029] In the key area of deep fissured rock mass, Voronoi diagram method is used to randomly arrange drill holes, the diameter of drill hole is 25-75 mm, the depth of drill hole is about 5-10 m, and the distance between drill holes is 2-5 m (which can be adjusted according to the size of surrounding rock and structural characteristics). The panoramic digital borehole camera system is used to obtain the 360° crack distribution image of the hole wall, and the skeletonization processing and spatial coplanarity criterion two-stage clustering algorithm are used to realize the high-precision statistics of the crack number, area, opening and extension direction of deep fissured rock mass.

[0030] Step 1.2.1: In the stress concentration area, the intersection area of structural plane and the area where the surrounding rock excavation disturbance is significant, the Voronoi diagram method is used to determine the drill hole arrangement position, so that the drill hole distribution covers different stress sections and structural units as much as possible.

[0031] Step 1.2.2: Digital borehole imaging acquisition and image preprocessing.

[0032] The panoramic digital borehole camera probe is slowly pushed to the bottom of the hole, and the hole wall panoramic image is taken in 360° rotation mode during the pullback process. In order to ensure that the crack opening can be identified, the hole wall is pre-sprayed with fluorescent agent or the contrast is enhanced by using LED ring light source, and finally the hole wall development image (developed into a two-dimensional strip image) is obtained, which is the digitalized original information of the crack distribution of deep rock mass. The original image is grayed, enhanced and noise filtered (median filter or Gaussian filter) to ensure clear crack boundary; the edge information is extracted using Canny operator to obtain crack edge profile; the polar coordinate → rectangular coordinate conversion of hole wall curved surface development coordinate system is carried out to facilitate subsequent geometric analysis.

[0033] Step 1.2.3: Skeleton extraction and feature recognition of crack.

[0034] The skeleton algorithm is used to thin the crack edge to obtain the crack centerline:

[0035] Wherein, E k represents the erosion operation, B ( x , y ) is the binary boundary of crack,S x y ) is the final skeleton.

[0036] Step 1.2.4: Fracture clustering and structural plane discrimination and extraction.

[0037] Calculate the dip direction α and dip angle β of each fracture skeleton, form a dataset {(α i , β i )}, according to the spatial coplanarity criterion:

[0038] where δ α , δ β is the preset tolerance (such as 10°), and the fractures are clustered. By two-stage clustering (first stage: intra-hole clustering; second stage: cross-hole spatial clustering), it is determined whether the fractures belong to the same structural plane or extended fractures.

[0039] Step 1.2.5: Quantitative extraction of fracture parameters and result statistics.

[0040] The number of fractures and the fracture area are calculated by the number of fracture skeletons and the closed contour of the fracture boundary:

[0041] where A A is the area of the fracture, used to represent the size of the fracture, Δ x , Δ y is the corresponding size of the pixel point in the actual space, Contour is the continuous boundary line of the fracture shape in the image, and p p is a single pixel point on the contour (Contour).

[0042] The opening is converted from the difference between the upper and lower boundary pixels to the actual length, and the calculation formula is as follows:

[0043] where W w is the average opening width between the two walls of the fracture, Δ n px is the difference between the upper and lower boundary pixels, Δ d px is the actual length corresponding to a single pixel, and M M is the magnification of the camera system.

[0044] The fracture parameters of different drill holes are spatially superimposed to form a three-dimensional fracture point cloud database; the number of fractures, average opening, distribution direction rose diagram and three-dimensional geometric model are output, realizing high-precision statistics of fracture characteristics of deep fracture rock mass. ​​

[0045] Step 1.3: Based on the fracture parameter distribution characteristics obtained by the "surface + deep exploration" method, the synergistic kriging method and the D-S evidence reasoning method are used to interpolate the three-dimensional fracture spatial position, fracture density and fracture occurrence characteristics, with borehole data as the main variable and surface data as the auxiliary variable.

[0046] Step 2: Based on the obtained three-dimensional fracture network distribution characteristics of deep rock mass, the C4D software is used to reconstruct and restore the three-dimensional fracture spatial distribution model of deep rock mass, and the test rock mass model with a certain length: width: height value is determined, and the rock sample containing three-dimensional fracture network is obtained by using 3D printing technology.

[0047] Step 3: Obtain the geometry and equivalent mechanical parameters of the deep fractured rock mass characterization unit.

[0048] The three-dimensional fracture network rock mass model obtained by 3D printing is used for uniaxial and triaxial compression indoor test by using rock servo test machine, and the variation law of mechanical parameters (uniaxial compressive strength, elastic modulus, Poisson's ratio, cohesion, internal friction angle) of fractured rock mass under different sizes is obtained, as shown in Figure 3 The variation coefficient and difference ratio of mechanical parameters are compared to determine the size of the deep fractured rock mass characterization unit, determine the equivalent mechanical parameters of the deep fractured rock mass characterization unit, and determine the DEM particle micro-mechanical parameters corresponding to the equivalent mechanical parameters.

[0049] In this embodiment, the threshold is set to 15%, and when the variation coefficient and the absolute value of the difference ratio are both less than 15%, the synthesized rock mass size is the characterization unit size, and the uniaxial and triaxial compression discrete element numerical simulation experiment of the characterization unit is carried out. When the curves are consistent, the particle discrete element micro-mechanical parameters are consistent with the mechanical parameters of the characterization unit.

[0050] Step 4: Determine the range of excavation disturbed zone of deep fractured rock mass D .

[0051] Step 4.1: Determine the range of excavation disturbed zone by engineering analogy method D 1.

[0052] Collect technical data of similar projects to the proposed underground project, collect measured data of the excavation disturbance range of the project, and use mathematical statistical method to average the excavation disturbance range of different projects to obtain the range of surrounding rock disturbance zone D 1.

[0053] Step 4.2: Determine the range of excavation disturbed zone by theoretical analysis method D 2.

[0054] Based on the geological survey data of the proposed deep underground engineering project, the excavation radius of the underground engineering project will be determined. R Initial geostress P 0. Support force during excavation stage P i (Take 0 when there is no support), cohesion c internal friction angle φ The range of the excavation disturbance zone in underground engineering is calculated using Fenner's formula based on the Mohr-Coulomb criterion, thus determining the theoretical calculation range. D 2.

[0055] .

[0056] Step 4.3: Determine the excavation disturbance area D 1. Excavation disturbance range D 2. Compare the values ​​and use the larger value for excavation disturbance as the extent of the excavation disturbance zone. D .

[0057] Step 5: Continuous-discontinuous numerical simulation calculation of deep fractured rock mass.

[0058] Step 5.1: Based on the on-site engineering geological conditions, establish a three-dimensional numerical model; for the excavation disturbance area near the tunnel... D The DEM particle method was used for modeling in the inner field, while the FDM method was used for modeling in other far-field regions.

[0059] Step 5.2: Assign the macroscopic characterization unit mechanical parameters and their corresponding particle micromechanical parameters determined in Step 3 to the FEM mesh in the distant unexcavated area and the DEM particles in the nearby excavated disturbance area, respectively.

[0060] Step 5.3: The FDM and DEM are used to perform information transfer calculations using an overlapping coupling method. In the overlapping coupling region of the FDM and DEM, a hyperbolic function is used to ensure a smooth energy transition between the two regions. The energy smooth transition formula is as follows:

[0061] In the formula, H Hamiltonian energy represents the total energy within a system, which is the sum of kinetic and potential energy. H FDM The Hamiltonian energy of a continuous medium; H DEM For discrete particles, the Hamiltonian energy is given. α The linear combination coefficients of energy are within the overlapping region. α The value changes linearly from 0 to 1. γ The curvature coefficient of the curve; β It is the coefficient of the peak value of physical quantities in a continuous region.

[0062] Step 6: Tunnel excavation simulation under multiple working conditions is carried out.

[0063] The engineering rock mass model containing continuous-discontinuous regions established through steps 1-5 improves the accuracy of continuous-discontinuous coupling calculation. Based on this, tunnel excavation simulation is carried out, and surrounding rock stability analysis is conducted to provide a reasonable optimization design basis for engineering construction.

[0064] Example 2 This example uses the method described in Example 1 to illustrate in detail with a deep fractured rock mass as the engineering background, including the following steps: Step 1: Fractured rock mass distribution characteristics of deep underground engineering are detected.

[0065] Step 1.1: The southwest tunnel project to be built is a deep engineering project, facing complex geological conditions such as high ground stress, high ground temperature, and high seepage pressure. The pre-investigation report shows that the surrounding rock is relatively fractured and broken, and large deformation and rock burst disasters are likely to occur during construction.

[0066] According to the distribution characteristics of the deep tunnel surrounding rock fractures, the key area is determined to be about 50m behind the working face. First, a Leica BLK360 three-dimensional laser scanner is used to conduct overall macroscopic fracture scanning detection in the key area, obtaining the distribution characteristics of the tunnel macroscopic fractures. Second, a ContextCapture + Canon EOS R5 photogrammetry system is used to identify the fractures within a 10m x 10m range in the key area to obtain the fracture distribution characteristics. Third, a measurement window method is used to randomly identify the microscopic fracture characteristics in the key area. Finally, the fracture distribution information obtained from the overall to the local is normalized and processed to obtain the surface distribution characteristics of the deep fractured rock mass.

[0067] Step 1.2: In the key area of the deep fractured rock mass, a Voronoi diagram method is used to randomly arrange drill holes with a diameter of 50mm and a depth of about 7.5m. A panoramic digital borehole camera system is used to obtain 360° fracture distribution images of the hole wall. Through skeletonization processing and spatial coplanarity criterion two-stage clustering algorithm, high-precision statistics of fracture parameters such as number, area, opening, and extension direction of the deep fractured rock mass are realized.

[0068] Step 1.3: Based on the fracture parameter distribution characteristics obtained by the "surface + deep detection" method, a collaborative kriging method and a D-S evidence reasoning method are used to interpolate with drill hole data as the main variable and surface data as the auxiliary variable to obtain characteristic parameters such as three-dimensional fracture spatial position, fracture density, and fracture occurrence.

[0069] Step 2: Based on the obtained three-dimensional fracture network distribution characteristics of deep rock masses, the three-dimensional fracture spatial distribution model of deep rock masses is reconstructed and restored using C4D software. A test rock mass model with a length:width:height ratio of 1:1:2 (height 100mm~140mm) is randomly defined, and 3D printing technology is used to obtain the model as shown below. Figure 2 The experimental model shown contains a three-dimensional fracture network.

[0070] Step 3: The 3D fractured rock mass model obtained through 3D printing is subjected to uniaxial and triaxial compression chamber tests using a rock servo testing machine to obtain the variation patterns of mechanical parameters (uniaxial compressive strength, elastic modulus, Poisson's ratio, cohesion, and internal friction angle) of the fractured rock mass at different sizes. Figure 3 As shown, by comparing the coefficient of variation and the difference ratio, the size of the characterizing unit of the fractured rock mass is determined to be 80mm×80mm×160m. The corresponding macroscopic and microscopic equivalent biomechanical parameters are shown in Table 1 and Table 2.

[0071] Table 1 Macroscopic equivalent mechanical parameters of fractured rock mass

[0072] Table 2. Microscopic equivalent mechanical parameters of fractured rock mass

[0073] Step 4: Determine the extent of the disturbance zone during excavation of deep fractured rock mass D .

[0074] Step 4.1: Determine the extent of the excavation disturbance zone using the engineering analogy method. D 1.

[0075] Data on the excavation disturbance range of existing projects A, B, and C, which have similar geological conditions to the proposed project, were collected. The excavation disturbance thicknesses of existing projects A, B, and C were found to be 15, 21, and 25 m, respectively. The range of the surrounding rock disturbance zone was then comprehensively determined. D 1 is 20.3m.

[0076] Step 4.2: Determine the extent of the excavation disturbance zone using theoretical analytical methods. D 2.

[0077] Proposed tunnel excavation radius R The initial ground stress is 5m. P 0 represents 20 MPa, the support force during the excavation stage. P i The cohesion of the rock mass is 0. c 5MPa, internal friction angle φ The angle is 20°. Substituting the above parameters into the calculation formula (1), the range of the excavation disturbance zone of the proposed project is calculated. D2 is 22 m.

[0078] .

[0079] Step 4.3: Theoretical analytical method to obtain the excavation disturbance range D 1 Engineering analogy method to obtain the excavation disturbance range D 2 Comparison and selection of the larger value of the excavation disturbance range to determine the excavation disturbance zone range as 22 m.

[0080] Step 5: Deep fracture rock mass continuous-discontinuous numerical simulation calculation method.

[0081] Step 5.1: Based on the site engineering geological conditions, a three-dimensional numerical model is established, with a model size of 400 m long, 400 m wide, and 320 m high. The tunnel is circular with a radius of 5 m. The DEM particle method is used for modeling within 22 m around the proposed tunnel, and the FDM method is used for model construction in the other far-field area. The model profile is shown in Figure 4 .

[0082] Step 5.2: The macroscopic characterization unit mechanical parameters determined in step 3 are assigned to the FEM grid in the far-field unexcavated area and the DEM particles in the near-field excavation disturbance range.

[0083] Step 5.3: FDM and DEM use overlapping coupling method for information transmission calculation. In the overlapping coupling area of FDM and DEM, a hyperbolic function is used to ensure smooth transition of energy between the two areas. The energy smoothing transition formula is as follows:

[0084] In the formula, H is the Hamilton energy, representing the total energy in a system, which is the sum of kinetic energy and potential energy; H FDM is the Hamilton energy of continuous medium; H DEM is the Hamilton energy of discrete particles; α is the linear combination coefficient of energy, which changes linearly from 0 to 1 in the overlapping domain, α is the curvature coefficient of the curve; γ is the coefficient of the peak value of the physical quantity in the continuous area. β

[0085] Step 6: Tunnel excavation simulation under multiple working conditions.

[0086] ​Based on the engineering rock mass model containing continuous-discontinuous regions established in steps 1-5, tunnel excavation simulation is carried out, and measuring lines are set at the tunnel vault, left and right spandrels, and left and right springers, which are compared with the field monitoring data to analyze the stability of surrounding rock.

[0087] Embodiment 3: The embodiment provides a deep fissure rock mass stability numerical simulation analysis system, comprising: The rock mass distribution characteristic acquisition module is used for acquiring the deep fissure rock mass distribution characteristic based on full-scale and internal scanning; The rock sample printing module is used for establishing a three-dimensional fissure space distribution model based on the deep fissure rock mass distribution characteristic, and printing out a rock sample containing a three-dimensional fissure network by 3D printing; The micro-mechanical parameter determination module is used for performing indoor tests by using the rock sample to obtain the mechanical parameter variation law of the fissure-containing rock mass under different sizes; the equivalent mechanical parameters of the rock mass representation unit and the corresponding DEM particle micro-mechanical parameters are determined by comparing the mechanical parameter variation coefficient and the difference ratio; The excavation disturbance zone range determination module is used for comparing the excavation disturbance zone ranges obtained by the engineering analogy method and the theoretical analysis method, and taking the larger range as the excavation disturbance zone range; The rock mass model construction module is used for establishing a continuous-discontinuous region rock mass model based on the excavation disturbance zone range to perform tunnel excavation simulation.

[0088] Embodiment 4: The embodiment of the present application also provides an electronic device comprising a memory and a processor and computer instructions stored in the memory and running on the processor, and when the computer instructions are run by the processor, the steps in the deep fissure rock mass stability numerical simulation analysis method in embodiment 1 are completed.

[0089] Embodiment 5: The embodiment provides a computer readable storage medium for storing computer instructions, and when the computer instructions are executed by a processor, the steps in the deep fissure rock mass stability numerical simulation analysis method in embodiment 1 are completed.

[0090] The above only describes the preferred embodiments of the present application and is not used to limit the present application. For those skilled in the art, the present application can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A numerical simulation analysis method for the stability of deep fractured rock masses, characterized in that, include: Based on full-scale and internal scanning, the distribution characteristics of deep fractured rock masses were obtained; Based on the distribution characteristics of deep fractured rock masses, a three-dimensional fracture spatial distribution model was established, and a rock sample containing a three-dimensional fracture network was 3D printed. Indoor tests were conducted using the rock samples to obtain the variation law of mechanical parameters of fractured rock masses of different sizes; by comparing the coefficient of variation and the difference ratio of mechanical parameters, the equivalent mechanical parameters of the rock mass characterization unit and the corresponding micromechanical parameters of DEM particles were determined. The excavation disturbance zone range was obtained by comparing the engineering analogy method and the theoretical analysis method, and the larger range was taken as the excavation disturbance zone range. A continuous-discontinuous rock mass model was established based on the excavation disturbance zone to simulate tunnel excavation.

2. The numerical simulation analysis method for the stability of deep fractured rock masses according to claim 1, characterized in that, Three-dimensional laser scanning was used to scan the surface of deep fractured rock masses to obtain the overall distribution characteristics of fractures in the surrounding rock; photogrammetry was used to identify fractures in key areas to obtain the distribution characteristics of fractures in key areas; and windowing method was used to measure local fractures to obtain the distribution characteristics of local fractures. The distribution characteristics of fractures in the overall surrounding rock, the distribution characteristics of fractures in key areas, and the distribution characteristics of fractures in local surrounding rock were normalized and integrated to obtain the surface distribution characteristics of deep fractured rock masses.

3. The numerical simulation analysis method for the stability of deep fractured rock masses according to claim 2, characterized in that, A weighted fusion method is used to use the 3D laser scanning results as the background framework, and the measurement results of photogrammetry and windowing method as supplements.

4. The numerical simulation analysis method for the stability of deep fractured rock masses according to claim 1, characterized in that, In key areas, boreholes were laid out using the Voronoi diagram method to obtain 360° images of the fracture distribution on the borehole walls, quantitatively extracting fracture parameters, and spatially superimposing the fracture parameters of different boreholes to form a three-dimensional fracture point cloud database.

5. The numerical simulation analysis method for the stability of deep fractured rock masses according to claim 4, characterized in that, To determine the distribution characteristics of fracture parameters, interpolation was performed using borehole data as the main variable and surface data as the auxiliary variable to obtain the three-dimensional fracture spatial characteristic parameters.

6. A numerical simulation analysis method for the stability of deep fractured rock masses according to claim 1 or 5, characterized in that, Based on the distribution characteristics of three-dimensional fracture networks, a three-dimensional fracture spatial distribution model of deep rock mass was reconstructed and restored using C4D software. An experimental rock mass model was formed according to the defined dimensions, and then a rock sample containing a three-dimensional fracture network was obtained using 3D printing technology.

7. The numerical simulation analysis method for the stability of deep fractured rock masses according to claim 1, characterized in that, The process of establishing the continuous-discontinuous region rock mass model includes: First, a three-dimensional numerical model is established. The DEM particle method is used to model the area near the tunnel where excavation disturbance occurs, while the FDM method is used to model other far-field areas. The macroscopic characterization unit mechanical parameters and their corresponding particle microscopic mechanical parameters are respectively assigned to the FEM mesh in the distant unexcavated area and the DEM particles in the nearby excavated disturbance range. An overlapping coupling method is used for information transfer calculation. In the overlapping coupling region of FDM and DEM, a hyperbolic function is used to make the energy transition smoothly between the two regions.

8. A numerical simulation and analysis system for the stability of deep fractured rock masses, characterized in that, include: The rock mass distribution feature acquisition module is used to acquire the distribution features of deep fractured rock masses based on full-scale and internal scanning. The rock sample printing module is used to establish a three-dimensional fracture spatial distribution model based on the distribution characteristics of deep fractured rock masses, and to 3D print rock samples containing a three-dimensional fracture network. The micromechanical parameter determination module is used to conduct indoor tests using the rock samples to obtain the variation law of mechanical parameters of fractured rock masses of different sizes; by comparing the coefficient of variation and the difference ratio of mechanical parameters, the equivalent mechanical parameters of the rock mass characterization unit and the corresponding micromechanical parameters of DEM particles are determined. The module for determining the extent of the excavation disturbance zone is used to compare the extent of the excavation disturbance zone obtained through engineering analogy and theoretical analysis, and to take the larger extent as the extent of the excavation disturbance zone. The rock mass model building module is used to build continuous-discontinuous rock mass models based on the excavation disturbance zone for tunnel excavation simulation.

9. An electronic device, characterized in that, It includes a memory and a processor, as well as computer instructions stored in the memory and running on the processor, which, when executed by the processor, complete the steps in the numerical simulation analysis method for the stability of deep fractured rock masses as described in any one of claims 1-7.

10. A computer-readable storage medium, characterized in that, Used to store computer instructions, which, when executed by a processor, complete the steps in the numerical simulation analysis method for the stability of deep fractured rock masses as described in any one of claims 1-7.

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