Simplified Analysis Method for the Overall Seismic Response of Subway Depot, Platform and Cover Structure

Abstract

The invention discloses a simplified analysis method for the overall seismic response of a subway depot, platform and cover structure, which relates to the technical field of road construction. The method includes decomposing the overall three-dimensional model of the subway depot, platform and cover structure into soil, the three-dimensional model of the subway depot, and the three-dimensional models of the platform and cover structure; respectively establishing a first plane analysis model of the subway depot and the platform, a second plane analysis model of the platform and cover structure, and a plane integral analysis model of the overall structure; respectively comparing and analyzing the seismic responses of the first plane analysis model, the second plane analysis model and the plane integral analysis model, and establishing an influence spectrum curve of the cover structure on the seismic response of the depot and an influence spectrum curve of the subway depot on the seismic response of the cover structure. The invention comprehensively considers the interaction between the above-ground and underground structures during an earthquake, realizes efficient calculation of the seismic response, and the simplified analysis method based on the influence spectrum curve greatly improves the calculation efficiency compared with the three-dimensional dynamic time-history analysis.

Description

Technical Field

[0001] The present invention relates to the technical field of road construction, and specifically to a simplified analysis method for the overall seismic response of a subway depot, platform, and superstructure Background Art

[0002] With the in-depth development of urban rail transit and in order to efficiently utilize the limited urban land resources, the mode of property development relying on the subway depot of urban rail transit has been favored, resulting in an organic whole formed by the subway depot and the superstructure group through a large platform. When an earthquake occurs, complex interaction effects are generated between the subway depot and the superstructure group through the large platform, and this effect will significantly change the seismic response of the subway depot itself and the superstructure group. However, most of the current studies only consider the seismic response of underground structures or above-ground structures separately, ignoring the mutual influence between them, resulting in inaccurate safety assessments of underground and surface structures under seismic action in actual engineering, and it is difficult to meet the requirements of seismic design and safety assessment of urban rail transit engineering structures. The current deficiencies are mainly reflected in the following aspects:

[0003] 1) Model fragmentation: Traditional research analyzes underground and above-ground structures as independent systems, ignoring the influence of interaction on the seismic response of underground structures, surface structures, and the overall system;

[0004] 2) Distorted input excitation: The disturbance of the surface wave propagation path caused by the existence of underground structures is not considered in the seismic ground motion input, resulting in an input load error of more than 30%.

[0005] 3) Computational efficiency bottleneck: There is a risk of memory overflow when the traditional finite element method processes models with tens of millions of degrees of freedom, and there is a lack of simplified and practical calculation methods.

[0006] Under the background and trend of the integrated development of underground and surface structures, the seismic design of the overall system of underground and surface structures is particularly crucial, and its research is of great significance for improving the seismic performance of the overall integration and optimizing urban disaster prevention and mitigation strategies. Summary of the Invention

[0007] Aiming at the above deficiencies, the purpose of the present invention is to provide a simplified analysis method for the overall seismic response of a subway depot, platform, and superstructure. The overall idea of this method is to first decompose complex problems, establish the influence spectrum curves of corresponding factors through comparative analysis, and then combine them to obtain a simplified analysis method for the overall system.

[0008] Therefore, a simplified analysis method for the overall seismic response of a subway depot, platform, and cover structure of the present invention includes decomposing the overall three-dimensional model of the subway depot, platform, and cover structure into soil, the three-dimensional model of the subway depot, and the three-dimensional models of the platform and cover structure; respectively establishing a first plane analysis model of the subway depot and the platform, a second plane analysis model of the platform and cover structure, and a plane integral analysis model of the overall structure; respectively comparing and analyzing the seismic responses of the first plane analysis model, the second plane analysis model, and the plane integral analysis model, and establishing an influence spectrum curve of the cover structure on the seismic response of the depot and an influence spectrum curve of the subway depot on the seismic response of the cover structure.

[0009] Further, the establishment of the first plane analysis model includes: selecting a cross-section of the subway depot with typical characteristics, establishing a corresponding two-dimensional plane analysis model, and calculating the seismic response of the structure; verifying the rationality of the numerical analysis method through the shaking table test of the subway depot; using the verified numerical method to carry out numerical parameter analysis of key influencing factors for the subway depot to obtain the general seismic response law of the subway depot structure; comparing and analyzing the seismic responses of different characteristic cross-sections and the actual subway depot, and analyzing and determining the spatial irregular spectrum curve of each characteristic cross-section; based on the determined irregular spectrum curve, establishing a plane analysis model of the soil and the characteristic cross-section of the subway depot considering the structural irregular characteristics.

[0010] Further, the numerical parameter analysis of key influencing factors includes: the dimensions and burial depth of the depot structure, the shear wave velocity and soft interlayer of the site soil, the type, amplitude, and coherent / non-coherent of the seismic wave in terms of ground motion; the comparative analysis of the seismic responses of different characteristic cross-sections and the actual subway depot includes comprehensive analysis from the perspectives of structural acceleration, internal force, and deformation.

[0011] Further, respectively establish three-dimensional analysis models of the single platform and cover structure and the platform and cover structure group, compare and analyze the seismic response laws of the single structure model and the structure group model, respectively obtain the spectrum curves of each influencing factor, and based on the obtained spectrum curves, establish a simplified plane analysis model of the platform and cover structure.

[0012] Further, when establishing the second plane analysis model, it also includes verifying the rationality of the numerical analysis method by using the shaking table test; based on the verified numerical analysis method, carrying out numerical parameter analysis of key influencing factors, including the platform dimensions and constraint conditions of the platform, the number of structures, structure height, structure spacing, and structure type of the structure, and comparing and analyzing the seismic response laws of the single structure and the structure group.

[0013] Furthermore, the modeling of the overall three-dimensional model includes: determination of the calculation range, establishment of the calculation model, mesh division and element type, constitutive model and calculation parameters, contact treatment, boundary conditions, damping setting, dynamic time step, and seismic ground motion input.

[0014] Furthermore, the determination of the calculation range includes that the transverse calculation width takes 7 times the structural width, the longitudinal calculation length is equal to the structural length, and the vertical calculation depth depends on the bedrock surface depth of the local stratum; establishment of the calculation model: according to the actual structural dimensions and the soil calculation range, write the corresponding code program based on the parametric design language of BIM or other software to quickly realize different relative structural position relationships, so as to realize an efficient modeling method for the overall model; mesh division and element type: the soil uses 10-node tetrahedral elements, and the above-ground and underground structures are discretized by structural elements; constitutive model and calculation parameters: the soil uses the Davidenkov equivalent linearization model to consider the nonlinear characteristics of the soil, while the structure uses the plastic damage model of concrete; contact treatment: the normal direction uses hard contact to avoid intrusion, the tangential friction uses the Coulomb model, and the shear coefficient is 0.5; boundary conditions: use lateral binding boundaries, that is, make the nodes at the same height of the model have the same horizontal displacement to simulate the shear deformation of the soil during an earthquake; damping setting: use the classical Rayleigh damping model, and the Rayleigh damping coefficient is determined by calculating the system frequency; dynamic time step: at least 10 calculation steps within the time interval of the seismic ground motion record; seismic ground motion input: use the method of inputting seismic ground motion in sub-regions at the bottom of the model to consider the traveling wave effect of seismic waves.

[0015] Furthermore, after constructing the simplified plane integral analysis model of the soil, the subway vehicle depot, the platform, and the superstructure on the cover, verify its rationality using the results of the shaking table test.

[0016] Furthermore, compare and analyze the results of the first plane model with the seismic response of the plane integral analysis model, analyze the influence of the platform and the superstructure on the cover on the seismic response of the subway vehicle depot, and based on numerical parameter analysis, establish the influence spectrum curve of the superstructure on the cover on the seismic response of the vehicle depot, and accordingly establish a simplified seismic analysis method for the subway vehicle depot considering the influence of the platform and the superstructure on the cover.

[0017] Furthermore, compare and analyze the results of the second plane model with the seismic response of the plane integral analysis model, analyze the influence of the subway vehicle depot on the seismic response of the platform and the superstructure on the cover, and based on numerical parameter analysis, establish the influence spectrum curve of the subway vehicle depot on the seismic response of the superstructure on the cover, and accordingly establish a simplified seismic analysis method for the platform and the superstructure on the cover considering the influence of the subway vehicle depot.

[0018] The beneficial technical effects of the present invention:

[0019] A simplified analysis method for the overall seismic response of a subway depot, platform and covered structure of the present invention realizes efficient calculation of the seismic response of the overall system of the subway depot - large platform - covered structure group by establishing a three-dimensional dynamic coupling model of the subway depot, large platform and covered surface structure group, comprehensively considering the interaction of the overall subway depot - large platform - surface structure group during an earthquake, and considering the correction of the seismic wave propagation path, and proposes a simplified analysis method based on the influence spectral curve, which greatly improves the calculation efficiency compared with the three-dimensional dynamic time history analysis.

[0020] The specific embodiment of the present invention realizes the integrated overall consideration of the subway depot and the covered surface structure group, and proposes an efficient modeling method for the structural model imported by means such as BIM. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is the overall flow chart;

[0022] Figure 2 is an example diagram of the spatial irregular spectral curve of each characteristic section under different factors;

[0023] Figure 3 is the influence spectral curve diagram of the interaction between structures under different factors;

[0024] Figure 4 is a schematic diagram of the shaking table test of the soil body, subway depot, platform and covered structure group. DETAILED DESCRIPTION OF THE INVENTION

[0025] In order to further elaborate on the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following combines the drawings and preferred embodiments to detail the specific implementation manner, structure, features and their effects of the present invention as follows.

[0026] Referring to Figure 1 as shown, a simplified analysis method for the overall seismic response of a subway depot, platform and covered structure of the present invention includes decomposing the overall three-dimensional model of the subway depot, platform and covered structure into a soil, a three-dimensional model of the subway depot and a three-dimensional model of the platform and covered structure; respectively establishing a first plane analysis model of the subway depot and the platform, a second plane analysis model of the platform and covered structure, and a plane overall analysis model of the overall structure; respectively comparing and analyzing the seismic responses of the first plane analysis model, the second plane analysis model and the plane overall analysis model, and establishing an influence spectral curve of the covered structure on the seismic response of the depot and an influence spectral curve of the subway depot on the seismic response of the covered structure. The specific embodiment of the present invention includes 4 steps, specifically:

[0027] Step 1, overall modeling and seismic response analysis of the subway depot, soil body and surface structure. This model is a three-dimensional overall coupling calculation model, including:

[0028] (1)Determination of the calculation range: Based on the "Code for Seismic Design of Urban Rail Structures" and the specific dimensions of the subway depot, the corresponding calculation range is determined. Generally, the transverse calculation width is taken as 7 times the structural width, the longitudinal calculation length is equal to the structural length, and the vertical calculation depth depends on the bedrock surface depth of the location.

[0029] (2)Establishment of the calculation model: Based on the actual structural dimensions and the soil calculation range, write the corresponding code program using the parametric design language of BIM or other software (example below), which can quickly realize different relative structural position relationships, thus realizing an efficient modeling method for the overall model;

[0030] global W_station = 80.0; Width of the station (m)

[0031] global L_station = 400.0; Length of the station (m)

[0032] global H_station = 12.0; Height of the station (m)

[0033] global W_building = 120.0; Width of the surface structure (m)

[0034] global L_building = 100.0; Length of the surface structure (m)

[0035] global H_building = 120.0; Height of the surface structure (m)

[0036] global D_space = 10.0; Clear distance between the subway station and the surface structure (m)

[0037] global E_station = 35e9; Elastic modulus of the station (Pa)

[0038] global Density_station = 2500; Density of the station (kg / m3)

[0039] (3)Mesh generation and element type: The soil is adopted with 10-node tetrahedral elements, and the above-ground and underground structures are discretized with structural elements;

[0040] (4)Constitutive model and calculation parameters: The Davidenkov equivalent linearization model is adopted for the soil to consider the nonlinear characteristics of the soil, while the plastic damage model of concrete is adopted for the structure;

[0041] (5) Contact treatment: The normal contact is set to be hard to avoid intrusion, and the Coulomb model is adopted for the tangential friction with a shear coefficient of 0.5;

[0042] (6) Boundary conditions: The lateral binding boundary is adopted, that is, the nodes at the same height of the model have the same horizontal displacement to simulate the shear deformation of the soil during an earthquake;

[0043] (7) Damping setting: The classical Rayleigh damping model is adopted, and the Rayleigh damping coefficient is determined by calculating the system frequency;

[0044] (8) Dynamic time step: To ensure the effective propagation of ground motion response, it is recommended that there be at least 10 calculation steps within the time interval of the ground motion record (such as 0.02 s). Therefore, the dynamic time step can be set to 0.001 s or a smaller time step generated by the system, but the calculation efficiency should be considered to seek a balance between accuracy and efficiency;

[0045] (9) Ground motion input: For the calculation model corresponding to large underground structures, the spatial effect of ground motion cannot be ignored. This method adopts the method of inputting ground motion in sub-regions at the bottom of the model to consider the traveling wave effect of seismic waves.

[0046] Step 2: Establishment of the first plane analysis model, including:

[0047] (1) Select the cross-section of the subway depot with typical characteristics, establish the corresponding two-dimensional plane analysis model, and calculate the seismic response of the structure. At present, the seismic analysis method recommended by the Code for Seismic Design of Urban Rail Transit Structures is the in-plane response displacement method, but this method is only applicable to regular underground structures. Obviously, the response displacement method is not applicable to the complex subway depot structure with spatial characteristics. The above method can transform the complex spatial structure problem into a simple plane problem;

[0048] (2) Based on the completed shaking table test of the subway depot, verify the rationality of the numerical method;

[0049] (3) Use the verified numerical method to carry out numerical parameter analysis of key influencing factors on the full-scale subway depot, including: aspects of the depot structure (dimensions, burial depth, etc.), aspects of the site soil (shear wave velocity, soft interlayer), aspects of ground motion (type of seismic wave, amplitude, coherent / non-coherent, etc.), and obtain the general seismic response law of the subway depot structure;

[0050] (4) Compare and analyze the seismic responses of different characteristic cross-sections and the actual subway depot, and comprehensively analyze from the perspectives of structural acceleration, internal force and deformation to analyze and determine the spatial irregular spectral curves of each characteristic cross-section. Figure 2 One example is shown as follows;

[0051] (5) Based on the determined irregular spectral curve, establish a plane analysis model of the soil-subway depot characteristic section considering the structural irregular characteristics.

[0052] Step 3: Establishment of the second plane analysis model, including:

[0053] (1) For the covered structure group, establish 3D analysis models of the platform-covered single structure and the platform-covered structure group respectively;

[0054] (2) Use the shaking table test to verify the rationality of the numerical analysis method;

[0055] (3) Based on the verified numerical analysis method, carry out numerical parameter analysis of key influencing factors, including aspects of the platform (platform size, constraint conditions, etc.), structure (number of structures, structure height, structure spacing, structure type, etc.), compare and analyze the seismic response laws of the single structure and the structure group, and obtain the spectral curves of each influencing factor respectively, as shown in Figure 3 shown;

[0056] (4) Based on the obtained spectral curves, establish a simplified plane analysis model of the platform-covered structure, that is, the second plane analysis model.

[0057] Step 4: Simplified seismic analysis of the subway depot and the covered structure, including:

[0058] (1) Based on the first plane analysis model (soil, subway depot characteristic plane simplified analysis model) and the second plane analysis model (platform, covered structure plane simplified analysis model) established above, construct a plane overall analysis model (soil, subway depot, platform, covered structure simplified plane overall analysis model), and use the shaking table test results to verify its rationality;

[0059] (2) Compare and analyze the results of the first plane analysis model and the seismic response of the plane overall analysis model, analyze the influence of the platform and the covered structure on the seismic response of the subway depot, and based on the numerical parameter analysis, establish a spectral curve of the influence of the covered structure on the seismic response of the depot, and accordingly establish a simplified seismic analysis method of the subway depot considering the influence of the platform and the covered structure;

[0060] (3) Compare and analyze the results of the second plane model and the seismic response of the plane overall analysis model, analyze the influence of the subway depot on the seismic response of the platform and the covered structure, and based on the numerical parameter analysis, establish a spectral curve of the influence of the subway depot on the seismic response of the covered structure, and accordingly establish a simplified seismic analysis method of the platform and the covered structure considering the influence of the subway depot.

[0061] The above are only the preferred embodiments of the present invention, and do not impose any form of limitation on the present invention. Although the present invention has been disclosed above with the preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to equivalent embodiments with equivalent changes within the scope of the technical solution of the present invention. However, as long as it does not depart from the content of the technical solution of the present invention, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A simplified analysis method for the overall seismic response of subway depots, platforms and roof structures, characterized by: It includes decomposing the overall three-dimensional model of the subway depot, platform and cover structure into soil, subway depot three-dimensional model and platform, cover structure three-dimensional model; Establishing the first plane analysis model of the subway depot and platform, the second plane analysis model of the platform and the structure above the cover, and the plane overall analysis model of the overall structure respectively; Compare and analyze the seismic responses of the first plane analysis model, the second plane analysis model and the plane overall analysis model respectively, establish the spectrum curve of the seismic response of the cover structure on the vehicle depot, and the spectrum curve of the seismic response of the subway vehicle depot on the cover structure, and establish a simplified seismic analysis method for the subway vehicle depot considering the influence of the platform and the cover structure based on the spectrum curve of the seismic response of the cover structure on the vehicle depot, and establish a simplified seismic analysis method for the platform and the cover structure considering the influence of the subway vehicle depot based on the spectrum curve of the seismic response of the subway vehicle depot on the cover structure; The establishment of the first plane analysis model includes: A subway depot cross section with typical characteristics was selected, and a corresponding two-dimensional plane analysis model was established to calculate the seismic response of the structure. The rationality of the numerical analysis method was verified through a subway depot shaking table test. Use the verified numerical method to carry out numerical parameter analysis of key influencing factors on the subway depot and obtain the general seismic response law of the subway depot structure; Compare and analyze the seismic responses of different characteristic sections with those of the actual subway depot, and determine the spatial irregular spectrum curves of each characteristic section; Based on the determined irregular spectrum curve, a soil and subway depot characteristic cross-section plane analysis model is established considering the structural irregularity.

2. The simplified analysis method for the overall seismic response of a subway depot, platform and cover structure according to claim 1 is characterized by: Numerical parameter analysis of key influencing factors includes: size and burial depth of the depot structure, shear wave velocity and weak interlayer of the site soil, seismic wave type, amplitude, and consistency / inconsistency of the ground motion; Comparative analysis of the seismic responses of different characteristic sections and actual subway depots includes a comprehensive analysis from the perspectives of structural acceleration, internal forces and deformation.

3. The simplified analysis method for the overall seismic response of a subway depot, platform and cover structure according to claim 1 or 2, characterized in that: Three-dimensional analysis models of single structures on the platform and the cover and of the structure group on the platform and the cover are established respectively. The seismic response laws of the single structure model and the structure group model are compared and analyzed, and the spectral curves of each influencing factor are obtained respectively. Based on the obtained spectral curves, a simplified plane analysis model of the platform and the cover structure is established.

4. The simplified analysis method for the overall seismic response of a subway depot, platform and cover structure according to claim 3 is characterized by: It also includes the use of shaking table tests to verify the rationality of the numerical analysis method; Based on the verified numerical analysis method, numerical parameter analysis of key influencing factors is carried out, including platform size and constraints on the platform, number of structures, structure height, structure spacing, and structure type on the structure, and comparative analysis of the seismic response laws of single structures and structure groups.

5. The simplified analysis method for the overall seismic response of a subway depot, platform and cover structure according to claim 4 is characterized by: The modeling of the overall three-dimensional model includes: determination of calculation scope, establishment of calculation model, mesh division and unit type, constitutive model and calculation parameters, contact processing, boundary conditions, damping setting, dynamic time step, and seismic input.

6. The simplified analysis method for the overall seismic response of a subway depot, platform and cover structure according to claim 5 is characterized by: Determination of calculation range: the horizontal calculation width is 7 times of the structure width, the longitudinal calculation length is equal to the structure length, and the vertical calculation depth depends on the depth of the bedrock surface of the local formation; Establishment of calculation model: According to the actual structural size and soil calculation range, write corresponding code programs based on the parametric design language of BIM or other software to quickly realize the relative position relationship of different structures, thereby realizing an efficient modeling method for the overall model; Meshing and unit type: The soil body adopts 10-node tetrahedron unit, and the above-ground and underground structures adopt structural unit discretization; Constitutive model and calculation parameters: The Davidenkov equivalent linearization model is used for soil to consider the nonlinear characteristics of soil, while the plastic damage model of concrete is used for structure; Contact treatment: The normal direction uses hard connection to avoid intrusion, and the tangential friction uses the Coulomb model with a shear coefficient of 0.5; Boundary conditions: Lateral binding boundaries are used, which means that nodes at the same height of the model have the same horizontal displacement to simulate the shear deformation of the soil during an earthquake. Damping setting: The classic Rayleigh damping model is used, and the Rayleigh damping coefficient is determined by the system frequency calculation; Dynamic time step: at least 10 calculation steps within the time interval of ground motion records; Earthquake motion input: The traveling wave effect of seismic waves is taken into account by inputting earthquake motion into a certain area at the bottom of the model.

7. The simplified analysis method for the overall seismic response of a subway depot, platform and cover structure according to claim 6 is characterized by: After the simplified plane overall analysis model of soil, subway depot, platform and cover structure was constructed, its rationality was verified using the shaking table test results.

8. The simplified analysis method for the overall seismic response of a subway depot, platform and cover structure according to claim 7 is characterized by: The seismic response of the first plane model results and the plane overall analysis model are compared and analyzed, and the influence of the platform and the cover structure on the seismic response of the subway depot is analyzed. Based on numerical parameter analysis, the influence spectrum curve of the cover structure on the seismic response of the depot is established. Based on this, a simplified seismic analysis method for the subway depot considering the influence of the platform and the cover structure is established.

9. The simplified analysis method for the overall seismic response of a subway depot, platform and cover structure according to claim 8, characterized in that: The seismic responses of the second plane model results and the overall plane analysis model are compared and analyzed, and the influence of the subway depot on the seismic response of the platform and the cover structure is analyzed. Based on numerical parameter analysis, the influence spectrum curve of the subway depot on the seismic response of the cover structure is established. Based on this, a simplified seismic analysis method for the platform and the cover structure considering the influence of the subway depot is established.

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