Mechanical property analysis method for shield tunnel reinforced concrete duct piece

Abstract

The invention provides a mechanical property analysis method for a shield tunnel reinforced concrete segment. The method comprises the following steps: step 1, constructing an aggregate three-dimensional model database; 2, constructing a first aggregate accumulation model based on the aggregate three-dimensional model; 3, establishing a three-dimensional model of each part forming the concrete segment; step 4, constructing a three-dimensional model of the heterogeneous reinforced concrete duct piece; 5, constructing a stratum three-dimensional model and a grouting layer three-dimensional model; step 6, constructing a heterogeneous shield tunnel reinforced concrete segment three-dimensional model; and 7, carrying out stress analysis on the heterogeneous shield tunnel reinforced concrete segment three-dimensional model. According to the invention, the random distribution characteristics of the aggregate in the concrete and the interaction relationship between the aggregate and the concrete, between the reinforcing steel bar and the concrete and between the grouting layer can be reflected more truly, and the heterogeneity and complexity of the concrete microstructure can be captured more accurately, so that the mesomechanical characteristics of the duct piece in the stress process can be revealed more comprehensively.

Description

Technical Field

[0001] The invention relates to a mechanical property analysis method for a shield tunnel reinforced concrete segment, and belongs to the technical field of shield tunnel segment construction. Background Art

[0002] With the acceleration of urbanization, the development and utilization of underground space has become an essential component of modern urban construction. As an efficient and environmentally friendly tunnel construction method, shield tunneling is widely used in projects such as urban subways and underground pipeline corridors. However, in complex geological conditions, the segment structures of shield tunnels often face multiple challenges such as seepage, water pressure, and stratum heterogeneity, resulting in problems such as cracking, misalignment, leakage, and even localized collapse. Therefore, controlling the safety and stability of segment structures, especially ensuring their mechanical properties and durability in complex geological conditions, has long been a research hotspot in academia and engineering.

[0003] Currently, most mechanical performance analyses of tunnel shield segments are based on homogeneous concrete. This approach ignores the heterogeneous properties of aggregates and voids within the concrete material and fails to consider the influence of aggregate geometry on the stresses on the segment. This results in significant deviations between the final numerical simulation results and the actual stress distribution, crack propagation, and damage evolution of the segment under complex strata. Furthermore, mechanical performance analyses of tunnel shield segments are often performed using two-dimensional (2D) planar or cross-sectional models. These models exhibit significant deficiencies in characterizing spatial distribution characteristics, three-dimensional interactions between aggregates, and structural integrity. 2D models fail to fully capture the multi-scale spatial heterogeneity within concrete, limiting their application in studying mesoscopic damage evolution and fracture mechanisms. Therefore, overcoming the limitations of 2D modeling and developing a modeling approach that can realistically represent the spatial distribution of aggregates within concrete and the multi-interface interactions between aggregates, rebar, grouting layers, and strata has become a key technical challenge in improving the accuracy and applicability of mechanical performance analyses of shield segments. Summary of the Invention

[0004] The present invention provides a method for analyzing the mechanical properties of reinforced concrete segments in shield tunnels, which can more accurately capture the heterogeneity and complexity of the concrete microstructure, thereby more comprehensively revealing the micromechanical characteristics of the segments during stress loading.

[0005] To solve the above technical problems, the application provides a mechanical property analysis method of a shield tunnel reinforced concrete segment, comprising the following steps: step 1, constructing an aggregate three-dimensional model database: collecting two-dimensional images of a plurality of aggregate samples, and converting the two-dimensional images of each aggregate sample into an aggregate three-dimensional model through a voxelization method, and saving to the aggregate three-dimensional model database to construct the aggregate three-dimensional model database; step 2, constructing a first aggregate accumulation model based on the aggregate three-dimensional model, wherein the first aggregate accumulation model contains aggregates with multiple gradations and irregular shapes; step 3, determining the size of the concrete segment according to the engineering area design drawing, and establishing a three-dimensional model of each component constituting the concrete segment accordingly; the components of the concrete segment include four standard blocks, two connecting blocks and a wedge-shaped capping block; the four standard blocks are arranged between the two connecting blocks, the capping block is arranged between the two connecting blocks, and the components of the concrete segment are connected through bolts; step 4, constructing a non-homogeneous reinforced concrete segment three-dimensional model based on the first aggregate accumulation model and the three-dimensional model of each component of the concrete segment; step 5, constructing a stratum three-dimensional model and a grouting layer three-dimensional model according to the non-homogeneous reinforced concrete segment three-dimensional model; step 6, constructing a non-homogeneous shield tunnel reinforced concrete segment three-dimensional model: combining the non-homogeneous reinforced concrete segment three-dimensional model, the stratum three-dimensional model and the grouting layer three-dimensional model to generate a non-homogeneous shield tunnel reinforced concrete segment three-dimensional model based on the stratum structure method; and step 7, performing stress analysis on the non-homogeneous shield tunnel reinforced concrete segment three-dimensional model.

[0006] In a specific embodiment, step 2 is specifically: step 2.1, setting the generation domain of the aggregate in the discrete element software PFC according to the size of the concrete segment; step 2.2, setting the porosity and the aggregate gradation radius range, and generating circular aggregate models with different gradations in the generation domain through a particle generation algorithm to generate a circular aggregate model; step 2.3, replacing any circular aggregate in the circular aggregate model with a randomly extracted aggregate three-dimensional model from the aggregate three-dimensional model database until all the circular aggregates in the circular aggregate model are replaced with aggregate three-dimensional models to generate an initial aggregate accumulation model, wherein the equal-volume replacement principle is adopted to ensure that the volume of the replaced aggregate three-dimensional model is the same as the volume of the corresponding circular aggregate; and step 2.4, converting the initial aggregate accumulation model into a file format compatible with the finite element numerical analysis software ABAQUS through MATLAB to generate the first aggregate accumulation model.

[0007] In a specific embodiment, in step 2.3, the aggregate three-dimensional model is placed at the position of the corresponding circular aggregate based on a random angle and a random displacement.

[0008] In a specific embodiment, the step 3 is specifically: according to the size of the concrete segment, a three-dimensional model of each component constituting the concrete segment is constructed in the finite element numerical analysis software ABAQUS.

[0009] In a specific embodiment, the step 4 is specifically: step 4.1, the first aggregate accumulation model is cut to obtain seven second aggregate accumulation models respectively consistent with the shapes of the four standard blocks, two connecting blocks and one capping block of the concrete segment; step 4.2, the seven second aggregate accumulation models are imported into the finite element numerical analysis software ABAQUS, and each second aggregate accumulation model is combined with the corresponding component of the concrete segment by Boolean operation to generate the corresponding component of the concrete segment containing the second aggregate accumulation model; step 4.3, the components of the concrete segment containing the second aggregate accumulation model are spliced to form a non-homogeneous concrete segment three-dimensional model; step 4.4, bolts and steel bars are added to the non-homogeneous concrete segment three-dimensional model to construct a non-homogeneous reinforced concrete segment three-dimensional model.

[0010] In a specific embodiment, the step 7 specifically includes the following steps: step 7.1, material data of the engineering area of the non-homogeneous shield tunnel reinforced concrete segment three-dimensional model is given, and the interaction and contact relationship between the aggregate and the concrete, the steel bar and the concrete, the non-homogeneous reinforced concrete segment and the grouting layer, and the grouting layer and the stratum are set; step 7.2, the non-homogeneous shield tunnel reinforced concrete segment three-dimensional model is divided into grids; step 7.3, boundary conditions and loads of the engineering area of the non-homogeneous shield tunnel reinforced concrete segment three-dimensional model are given; step 7.4, the mechanical property of the non-homogeneous shield tunnel reinforced concrete segment three-dimensional model is analyzed by using the static general analysis step.

[0011] In a specific embodiment, the step 7.4 specifically includes: in the finite element numerical analysis software ABAQUS, a static general analysis step is created for the non-homogeneous shield tunnel reinforced concrete segment three-dimensional model, the time increment and the maximum number of increments are set, the nonlinear geometric effect is enabled, the output frequency is specified, the mechanical data is output in the definition field, the historical output variable is defined, and the displacement, reaction force and contact force time history of the nodes at the top, bottom and two side spandrel positions of the non-homogeneous shield tunnel reinforced concrete segment are recorded; the overall horizontal displacement, vertical settlement and convergence deformation of the non-homogeneous shield tunnel reinforced concrete segment are analyzed by using the visualization module of the finite element numerical analysis software ABAQUS.

[0012] In a specific embodiment, in the step 1, the two-dimensional images of a plurality of aggregate samples are collected by using the aggregate image analysis system AIMS2.

[0013] Compared with the prior art, the present application has the following beneficial effects.

[0014] 1、The application collects the two-dimensional image of the real aggregate to generate the aggregate three-dimensional model, generates the first aggregate accumulation model containing the aggregate with multi-gradation and irregular shape based on the aggregate three-dimensional model, generates the inhomogeneous reinforced concrete segment based on the first aggregate accumulation model, and further constructs the inhomogeneous reinforced concrete segment three-dimensional model of the shield tunnel and analyzes the stress of the same. The inhomogeneous reinforced concrete segment three-dimensional model of the shield tunnel can accurately simulate the aggregate distribution characteristics of the segment containing the aggregate with different particle sizes, different gradations and different porosities, and the interaction relationship between the aggregate, the concrete, the steel bar, the grouting layer and the stratum, can more accurately capture the non-uniformity and complexity of the concrete microstructure in the process of mechanical property analysis, and thus more comprehensively reveals the micro-mechanical characteristics of the segment in the stress process.

[0015] 2、The application can significantly improve the modeling efficiency and more conveniently and flexibly adjust the model parameters by constructing the first aggregate accumulation model containing the aggregate with multi-gradation and irregular shape through the discrete element software. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 The flowchart of the mechanical property analysis method of the reinforced concrete segment of the shield tunnel provided by the embodiment of the application is shown.

[0017] Figure 2 The first aggregate accumulation model provided by the embodiment of the application is shown.

[0018] Figure 3 The side view of the inhomogeneous reinforced concrete segment three-dimensional model provided by the embodiment of the application is shown.

[0019] Figure 4 The enlarged view of A in the middle. Figure 3

[0020] Figure 5 The inhomogeneous reinforced concrete segment three-dimensional model provided by the embodiment of the application is shown.

[0021] Legend: the inhomogeneous reinforced concrete segment three-dimensional model 1, the grouting layer three-dimensional model 2, the stratum three-dimensional model 3, and the aggregate three-dimensional model 4. DETAILED DESCRIPTION

[0022] The application will be described in detail below with reference to the embodiments and the drawings. It should be noted that the embodiments in the application and the features in the embodiments can be combined with each other without conflict.

[0023] Reference Figure 1 ​The application discloses a mechanical property analysis method of a shield tunnel reinforced concrete segment, and comprises the following steps: Step 1, constructing an aggregate three-dimensional model database: collecting two-dimensional images of a plurality of aggregate samples, and converting the two-dimensional images of each aggregate sample into an aggregate three-dimensional model through a voxelization method, and saving to the aggregate three-dimensional model database to construct the aggregate three-dimensional model database.

[0024] Specifically, in step 1, the two-dimensional images of the plurality of aggregate samples are collected by an aggregate image analysis system AIMS2.

[0025] Each aggregate two-dimensional image is subjected to denoising, binary segmentation, interlayer registration, aggregate contour extraction processing, and stacking along the vertical direction according to the layer spacing to generate a corresponding three-dimensional voxel matrix, and interpolation filling and surface smoothing optimization are performed on the three-dimensional voxel matrix to generate a corresponding aggregate three-dimensional model.

[0026] Step 2, constructing a first aggregate accumulation model based on the aggregate three-dimensional model, wherein the first aggregate accumulation model contains aggregate with multi-grade distribution and irregular shape.

[0027] In the embodiment, according to the design drawing of the engineering area, the specific size of the concrete segment is determined as follows: an outer diameter of 8.8 m, an inner diameter of 8 m, and a height of 1.8.

[0028] Preferably, step 2 is specifically as follows:

[0029] Step 2.1, according to the design drawing of the engineering area, the size of the concrete segment of the engineering area is determined, and the generation domain of the aggregate is set in the discrete element software PFC according to the size of the concrete segment, wherein the generation domain is a cuboid region with a length of 8.8 m, a width of 8.8 m and a height of 1.8 m.

[0030] Step 2.2, setting the porosity and the aggregate grade distribution radius range, generating different grade circular aggregates in the generation domain through a particle generation algorithm to generate a circular aggregate model.

[0031] Specifically, referring to the Concrete Quality Control Standard and actual construction experience, combined with the calculation requirements of the three-dimensional meso model of the discrete element, the minimum particle size of the circular aggregate in the circular aggregate model is set to 0.02 m, and the maximum particle size is set to 0.15 m. The circular aggregate is divided into three particle size gradations. The particle size d of the first particle size gradation of the circular aggregate ranges from 0.02 m to 0.04 m. The particle size d of the second particle size gradation of the circular aggregate ranges from 0.04 m to 0.08 m. The particle size d of the third particle size gradation of the circular aggregate ranges from 0.08 m to 0.15 m. The mass of the circular aggregate accounts for 10% of the mass of the concrete. The first particle size gradation accounts for 26.71% of the total circular aggregate. The second particle size gradation of the circular aggregate accounts for 36.61% of the total circular aggregate. The third particle size gradation of the circular aggregate accounts for 36.68% of the total circular aggregate. The particle size of each particle size gradation of the circular aggregate should meet the following requirements:

[0032] d x is the particle size to be solved; P(d x ) is the passing rate of the circular aggregate with a known particle size d x ; d1 is the smaller end value of the known particle size gradation, d2 is the larger end value of the known particle size gradation, P(d1) is the passing rate of the circular aggregate with a particle size d1, and P(d2) is the passing rate of the circular aggregate with a particle size d2.

[0033] Step 2.3, replace any circular aggregate in the circular aggregate model with a randomly selected aggregate three-dimensional model from the aggregate three-dimensional model database until all circular aggregates in the circular aggregate model are replaced with aggregate three-dimensional models to generate an initial aggregate accumulation model. The principle of equal volume replacement is adopted to ensure that the volume of the replaced aggregate three-dimensional model is the same as the volume of the corresponding circular aggregate.

[0034] Preferably, in step 2.3, the aggregate three-dimensional model is placed at the position of the corresponding circular aggregate based on a random angle and a random displacement, so that the aggregate three-dimensional model is more naturally distributed in the generation domain.

[0035] Step 2.4, convert the initial aggregate accumulation model to a file format compatible with the finite element numerical analysis software ABAQUS through MATLAB to generate a first aggregate accumulation model, refer to Figure 2 .

[0036] The file format of the initial aggregate accumulation model generated in the discrete element software is STL. The file format of the initial aggregate accumulation model is converted to IGES using MATLAB to facilitate import into the finite element numerical analysis software ABAQUS.

[0037] Step 3, according to the engineering area design drawings, the size of the concrete segment is determined, and the three-dimensional model of each component constituting the concrete segment is established accordingly; the components of the concrete segment include four standard blocks, two connecting blocks and a wedge-shaped top block; the four standard blocks are arranged between the two connecting blocks, and the top block is arranged between the two connecting blocks; the components of the concrete segment are connected by bolts; the wedge-shaped top block is adopted, which is matched with the space between the two connecting blocks to realize the geometric closure and structural stability of the concrete segment.

[0038] Specifically, step 3 is specifically: according to the size of the concrete segment of the engineering area, the three-dimensional model of each component constituting the concrete segment is constructed in the finite element numerical analysis software ABAQUS.

[0039] Step 4, based on the first aggregate accumulation model and the three-dimensional model of each component of the concrete segment, a three-dimensional model of the non-homogeneous reinforced concrete segment is constructed, referring to Figure 3 and Figure 4 .

[0040] Specifically, step 4 is specifically: step 4.1, the first aggregate accumulation model is cut to obtain seven second aggregate accumulation models respectively consistent with the shapes of the four standard blocks, two connecting blocks and a top block of the concrete segment.

[0041] Step 4.2, import the seven second aggregate accumulation models into the finite element numerical analysis software ABAQUS, combine each second aggregate accumulation model with the corresponding component of the concrete segment through Boolean operation to generate the corresponding component of the concrete segment containing the second aggregate accumulation model, and realize the random distribution of aggregate in each component of the concrete segment.

[0042] Step 4.3, splice the components of the concrete segment containing the second aggregate accumulation model to form a three-dimensional model of the non-homogeneous concrete segment.

[0043] Step 4.4, add bolts and steel bars to the three-dimensional model of the non-homogeneous concrete segment to construct a three-dimensional model of the non-homogeneous reinforced concrete segment, and the aggregate in the three-dimensional model of the non-homogeneous reinforced concrete segment is randomly distributed.

[0044] Create a three-dimensional line body with a radius of 1m as a bolt, and set two bolts at the connection of adjacent reinforced concrete segments, and the bolts are at the three points of the cross section of the non-homogeneous reinforced concrete segment.

[0045] Create a three-dimensional line body with a radius of 4.1m as a steel bar, which can be imported into the appropriate position of the non-homogeneous concrete segment through rotation and translation commands.

[0046] Step 5, according to the three-dimensional model of the non-homogeneous concrete segment, construct a three-dimensional model of the stratum and a three-dimensional model of the grouting layer.

[0047] A three-dimensional stretched entity in the shape of a cylinder with a diameter of 9 m is created, and then a cylinder with a diameter of 8.8 m is cut out at the center position to construct a three-dimensional model of a grouting layer with a thickness of 0.2 m.

[0048] A three-dimensional stretched entity in the shape of a cuboid with a length of 12 m, a width of 12 m, and a height of 1.8 m is created, and then a cylinder with a diameter of 9 m is cut out at the center position to construct a three-dimensional model of the stratum.

[0049] Step 6, constructing a three-dimensional model of a shield tunnel reinforced concrete segment: combining the three-dimensional model of the non-homogeneous reinforced concrete segment, the three-dimensional model of the stratum, and the three-dimensional model of the grouting layer to generate a three-dimensional model of a non-homogeneous shield tunnel reinforced concrete segment based on the stratum structure method, see Figure 5 .

[0050] Step 7, performing stress analysis on the three-dimensional model of the non-homogeneous shield tunnel reinforced concrete segment.

[0051] Specifically, the step 5 specifically includes the following steps: step 5.1, assigning material data to the three-dimensional model of the non-homogeneous shield tunnel reinforced concrete segment in the engineering area, and setting the interaction and contact relationship between the aggregate and the concrete, the steel and the concrete, the non-homogeneous reinforced concrete segment and the grouting layer, and the grouting layer and the stratum.

[0052] The aggregate is defined as a high-stiffness elastic body, the steel is modeled as an elastic-plastic model, the non-homogeneous reinforced concrete segment uses a concrete damage plastic model, the grouting layer considers elastic-plastic properties, and the stratum considers water-soil coupling behavior. By defining "surface-to-surface contact" and "embedded region" constraints, the mechanical transmission and interaction between the aggregate and the concrete, the steel and the concrete, the non-homogeneous reinforced concrete segment and the grouting layer, and the grouting layer and the stratum are simulated.

[0053] Step 5.2, dividing the three-dimensional model of the non-homogeneous shield tunnel reinforced concrete segment into a mesh.

[0054] Global seeds are set for the non-homogeneous reinforced concrete segment, the aggregate, the bolt, the steel, the grouting layer, and the stratum, and the global seed size of the non-homogeneous reinforced concrete segment, the aggregate, the bolt, and the steel is smaller than that of the grouting layer and the stratum.

[0055] The aggregate and the concrete interface is locally refined, and the irregular surface geometry is simplified by virtual topology.

[0056] The heterogeneous reinforced concrete segment and the aggregate are modeled by C3D10M tetrahedral elements, the grouting layer and the stratum are modeled by C3D8R hexahedral elements, the reinforcement is modeled by T3D2 truss elements or C3D8R solid elements according to the model type, and the water-soil coupling analysis of the stratum is modeled by C3D8P pore pressure elements. After the mesh is generated, the aspect ratio and the twist of the elements are checked, and the node alignment of the contact surfaces is ensured.

[0057] Step 5.3, the boundary conditions and the loads of the engineering region of the three-dimensional model of the heterogeneous shield tunnel reinforced concrete segment are given.

[0058] The setting of the boundary conditions specifically includes: fixing the bottom of the stratum to limit the displacement and rotation in the X, Y and Z directions, and restraining the side of the stratum to limit the displacement of the end of the heterogeneous reinforced concrete segment.

[0059] In the embodiment, the application of the loads specifically includes: applying uniform pressure on the outer surface of the heterogeneous reinforced concrete segment, applying uniform surface force on the top of the stratum, defining the initial stress field on the cross section of the prestressed reinforcement, and defining the gravity load in the global coordinate system according to the drilling columnar chart data of the engineering region.

[0060] The direction, the action region and the value of all the boundary conditions and the loads are verified to ensure that they are consistent with the corresponding information of the engineering region, so as to truly restore the stress state of the segment structure in the complex stratum.

[0061] Step 5.4, the mechanical performance analysis of the three-dimensional model of the heterogeneous shield tunnel reinforced concrete segment is performed by using the static general analysis step.

[0062] Specifically, in the step 5.4, the mechanical performance analysis of the three-dimensional model of the heterogeneous shield tunnel reinforced concrete segment is performed by using the static general analysis step, which specifically includes: in the finite element numerical analysis software ABAQUS, a static general analysis step is created for the three-dimensional model of the heterogeneous shield tunnel reinforced concrete segment, the time increment and the maximum number of increments are set, the nonlinear geometric effect is enabled, the output frequency is specified, the mechanical data is output in the definition field, the historical output variable is defined, and the displacement, the reaction force and the contact force time history of the nodes at the top, the bottom and the two side spandrel positions of the heterogeneous shield tunnel reinforced concrete segment are recorded; the overall horizontal displacement, the vertical settlement and the convergence deformation of the heterogeneous shield tunnel reinforced concrete segment are analyzed by using the visualization module of the finite element numerical analysis software ABAQUS, so as to evaluate the stress performance of the heterogeneous reinforced concrete segment and the stratum containing the aggregate accumulation model.

[0063] The above is further detailed description of the present application in combination with specific preferred embodiments, and cannot be deemed as limitation of the specific implementation of the present application to these descriptions. For those skilled in the art to which the present application belongs, without departing from the concept of the present application, a number of simple deductions and substitutions can be made, and all of them shall be deemed as falling within the protection scope of the present application.

Claims

1. A method for analyzing the mechanical properties of reinforced concrete segments of a shield tunnel, characterized in that: The following steps are involved: Step 1: Constructing an aggregate 3D model database: Collecting 2D images of multiple aggregate samples, converting the 2D images of each aggregate sample into an aggregate 3D model through a voxelization method, and saving the converted images to an aggregate 3D model database to construct an aggregate 3D model database; Step 2: constructing a first aggregate accumulation model based on the three-dimensional aggregate model, wherein the first aggregate accumulation model contains multi-graded and irregularly shaped aggregates; Step 3: Determine the dimensions of the concrete segments based on the project area design drawings, and build a three-dimensional model of the components that make up the concrete segments accordingly. The concrete segments consist of four standard blocks, two connecting blocks, and a wedge-shaped capping block. The four standard blocks are placed between the two connecting blocks, and the capping block is placed between the two connecting blocks. The various components of the concrete segments are connected by bolts. Step 4: constructing a heterogeneous reinforced concrete segment 3D model based on the first aggregate accumulation model and the 3D model of each component of the concrete segment; Step 5: constructing a 3D stratum model and a 3D grouting layer model based on the heterogeneous reinforced concrete segment 3D model; Step 6: Constructing a 3D model of a heterogeneous reinforced concrete segment of a shield tunnel: combining the 3D model of the heterogeneous reinforced concrete segment, the 3D model of the stratum, and the 3D model of the grouting layer to generate a 3D model of the heterogeneous reinforced concrete segment of a shield tunnel based on the stratum structure method; Step 7: Perform stress analysis on the three-dimensional model of the non-homogeneous reinforced concrete segments of the shield tunnel.

2. The mechanical properties analysis method of reinforced concrete segments of a shield tunnel according to claim 1, characterized in that: The step 2 is specifically as follows: Step 2.1: Set the aggregate generation domain in the discrete element software PFC according to the concrete segment size; Step 2.2: Set the porosity and aggregate gradation radius range, and generate circular aggregates of different gradations within the generation domain using the particle generation algorithm to generate a circular aggregate model. Step 2.3, replacing any circular aggregate in the circular aggregate model with a three-dimensional aggregate model randomly selected from the three-dimensional aggregate model database, until all circular aggregates in the circular aggregate model are replaced with the three-dimensional aggregate model, to generate an initial aggregate stacking model, wherein the equal volume replacement principle is used to ensure that the volume of the replaced three-dimensional aggregate model is the same as the volume of the corresponding circular aggregate; Step 2.4: Convert the initial aggregate stacking model into a file format compatible with finite element numerical analysis software ABAQUS through MATLAB to generate a first aggregate stacking model.

3. The mechanical properties analysis method of reinforced concrete segments of a shield tunnel according to claim 2, characterized in that: In step 2.3, the aggregate 3D model is placed at the position of the corresponding circular aggregate based on the random angle and random displacement.

4. The mechanical properties analysis method for reinforced concrete segments of a shield tunnel according to claim 3, characterized in that: The step 3 specifically includes: constructing a three-dimensional model of each component constituting the concrete segment in the finite element numerical analysis software ABAQUS according to the size of the concrete segment.

5. The mechanical properties analysis method of reinforced concrete segments of a shield tunnel according to claim 4, characterized in that: The step 4 is specifically as follows: Step 4.1, cutting the first aggregate accumulation model to obtain seven second aggregate accumulation models having shapes consistent with four standard blocks, two connecting blocks, and one capping block of the concrete segment; Step 4.2: Import the seven second aggregate accumulation models into the finite element numerical analysis software ABAQUS, and merge each second aggregate accumulation model with the corresponding concrete segment component through Boolean operations to generate the corresponding concrete segment component containing the second aggregate accumulation model; Step 4.3, splicing the concrete segment components containing the second aggregate accumulation model to form a heterogeneous concrete segment three-dimensional model; Step 4.4: Add bolts and steel bars to the heterogeneous concrete segment three-dimensional model to construct a heterogeneous reinforced concrete segment three-dimensional model.

6. The mechanical properties analysis method for reinforced concrete segments of a shield tunnel according to claim 5, characterized in that: The step 7 specifically includes the following steps: Step 7.

1. Assign material data to the engineering area of ​​the 3D model of the heterogeneous reinforced concrete segments of the shield tunnel, and set the interaction and contact relationships between aggregate and concrete, steel and concrete, heterogeneous reinforced concrete segments and grouting layers, and grouting layers and strata. Step 7.2, meshing the three-dimensional model of the inhomogeneous reinforced concrete segments of the shield tunnel; Step 7.3, assign boundary conditions and loads to the engineering area of ​​the three-dimensional model of the non-homogeneous reinforced concrete segments of the shield tunnel; Step 7.4: Use the static general analysis step to perform mechanical performance analysis on the three-dimensional model of the non-homogeneous reinforced concrete segments of the shield tunnel.

7. The mechanical properties analysis method for reinforced concrete segments of a shield tunnel according to claim 6, characterized in that: The step 7.4 specifically includes: in the finite element numerical analysis software ABAQUS, creating a static general analysis step for the three-dimensional model of the non-homogeneous shield tunnel reinforced concrete segment, setting the time increment and the maximum incremental step number, enabling nonlinear geometric effects, specifying the output frequency, outputting mechanical data in the defined field, defining historical output variables, and recording the displacement, reaction and contact force time history of the nodes at the top, bottom and spandrel positions of the non-homogeneous shield tunnel reinforced concrete segment; and analyzing the overall horizontal displacement, vertical settlement and convergence deformation of the non-homogeneous shield tunnel reinforced concrete segment through the visualization module of the finite element numerical analysis software ABAQUS.

8. The mechanical properties analysis method for reinforced concrete segments of a shield tunnel according to claim 1, characterized in that: In the step 1, two-dimensional images of multiple aggregate samples are collected by the aggregate image analysis system AIMS2.

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