Simplified analysis method for overall seismic response of metro depot, platform and cover structure

Abstract

The invention discloses a simplified analysis method for the overall seismic response of a metro depot, a platform and a cover structure, and relates to the technical field of road construction, and the method comprises the steps: decomposing an overall three-dimensional model of the metro depot, the platform and the cover structure into a three-dimensional model of the metro depot, the platform and the cover structure, and a three-dimensional model of the metro depot, the platform and the cover structure; respectively establishing a first plane analysis model of the metro depot and the platform, a second plane analysis model of the platform and the cover structure, and a plane overall analysis model of the overall structure; and respectively carrying out comparative analysis on seismic responses of the first plane analysis model, the second plane analysis model and the plane overall analysis model, and establishing an influence spectrum curve of the cover structure to the vehicle depot seismic response and an influence spectrum curve of the subway vehicle depot to the cover structure seismic response. According to the method, the interaction of the whole overground and underground structures during the earthquake is comprehensively considered, the efficient calculation of the earthquake response is realized, and compared with three-dimensional dynamic time-history analysis, the simplified analysis method based on the influence spectrum curve greatly improves the calculation efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of road construction, in particular to a simplified analysis method for the overall seismic response of a subway vehicle depot, a platform and a cover structure. Background Art

[0002] With the in-depth development of urban rail transit and in order to efficiently utilize the limited land resources in the city, the model of property development based on urban rail transit subway depots has gained favor, resulting in the subway depot and the roof structure group forming an organic whole through the large platform. When an earthquake occurs, the subway depot produces a complex interaction effect with the roof structure group through the large platform, which will significantly change the seismic response of the subway depot itself and the roof structure 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 assessment of underground and surface structures under earthquakes in actual projects, which is difficult to meet the needs of seismic design and safety assessment of urban rail transit engineering structures. The current deficiencies are mainly reflected in the following aspects: 1) Model split: Traditional studies analyze underground and aboveground structures as independent systems, ignoring the impact of interactions on underground structures, surface structures, and the seismic response of the overall system; 2) Input excitation distortion: The seismic input does not take into account the disturbance of underground structures on the surface wave propagation path, resulting in an input load error of more than 30%.

[0003] 3) Computational efficiency bottleneck: The traditional finite element method has the risk of memory overflow when processing models with tens of millions of degrees of freedom, and lacks simplified and practical calculation methods.

[0004] Under the general background and trend of integrated development of underground and surface structures, the seismic design of the overall system of underground and surface structures is particularly critical. Its research is of great significance to improving the overall seismic performance and optimizing urban disaster prevention and mitigation strategies. Summary of the invention

[0005] In view of the above shortcomings, the purpose of the present invention is to provide a simplified analysis method for the overall seismic response of subway depots, platforms and cover structures. The overall idea of ​​this method is to first decompose the complex problem, establish the corresponding spectrum curves of the influence of various factors through comparative analysis, and then combine them to obtain a simplified analysis method for the overall system.

[0006] To this end, the present invention provides a simplified analysis method for the overall seismic response of a subway depot, platform and cover structure, comprising decomposing the overall three-dimensional model of the subway depot, platform and cover structure into soil, a three-dimensional model of the subway depot and a three-dimensional model of the platform and cover structure; 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 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 respectively, and establishing a spectrum curve of the influence of the cover structure on the seismic response of the depot and a spectrum curve of the influence of the subway depot on the seismic response of the cover structure.

[0007] Furthermore, the establishment of the first plane analysis model includes: selecting a subway depot cross-section 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 a subway depot shaking table test; using the verified numerical method to conduct numerical parameter analysis of key influencing factors on the subway depot, and obtain the general seismic response law of the subway depot structure; comparing and analyzing the seismic responses of different characteristic sections with the actual subway depot, and analyzing and determining the spatial irregular spectral curve of each characteristic section; based on the determined irregular spectral curve, establishing a plane analysis model of soil and subway depot characteristic sections that takes into account the irregular characteristics of the structure.

[0008] Furthermore, the 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, consistency / inconsistency of ground motion; comparative analysis of the seismic response of different characteristic sections and the actual subway depot includes a comprehensive analysis from the perspectives of structural acceleration, internal force and deformation.

[0009] Furthermore, 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, and the seismic response laws of the single structure model and the structure group model are compared and analyzed. The spectral curves of each influencing factor are obtained respectively, and based on the obtained spectral curves, a simplified plane analysis model of the platform and the cover structure is established.

[0010] Furthermore, when establishing the second plane analysis model, it also includes using 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 a single structure and a group of structures.

[0011] Furthermore, the modeling of the overall three-dimensional model includes: determination of calculation scope, establishment of calculation model, meshing and unit type, constitutive model and calculation parameters, contact processing, boundary conditions, damping setting, dynamic time step, and seismic input.

[0012] Furthermore, the calculation range is determined by taking the lateral calculation width as 7 times 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 stratum; the establishment of the calculation model: according to the actual structure size and soil calculation range, the corresponding code program is written 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; mesh division and unit type: the soil adopts 10-node tetrahedron unit, and the above-ground and underground structures adopt structural unit discretization; constitutive model and calculation parameters: the soil adopts Davidenkov et al. The effective linearization model takes into account the nonlinear characteristics of the soil, while the structure adopts the plastic damage model of concrete; contact treatment: the normal direction adopts hard connection to avoid intrusion, the tangential friction adopts the Coulomb model, and the shear coefficient is 0.5; 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; damping setting: the classic Rayleigh damping model is adopted, 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 the seismic motion recording; seismic motion input: the method of inputting seismic motion in the bottom part of the model is used to consider the traveling wave effect of seismic waves.

[0013] Furthermore, a simplified plane overall analysis model of the soil, subway depot, platform, and cover structure was constructed, and its rationality was verified using the shaking table test results.

[0014] Furthermore, 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, a spectrum curve of the influence of the cover structure on the seismic response of the depot is established, and a simplified seismic analysis method for the subway depot considering the influence of the platform and the cover structure is established.

[0015] Furthermore, 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, and a simplified seismic analysis method for the platform and the cover structure considering the influence of the subway depot is established.

[0016] Beneficial technical effects of the present invention: The present invention provides a simplified analysis method for the overall seismic response of a subway depot, platform and cover structure. By establishing a three-dimensional dynamic coupling model of the subway depot, large platform and cover surface structure group, the overall interaction of the subway depot-large platform-surface structure group during an earthquake is comprehensively considered, and the correction of the seismic wave propagation path is considered to achieve efficient calculation of the seismic response of the subway depot-large platform-cover structure group as a whole system. A simplified analysis method based on the influence spectral curve is proposed, which greatly improves the calculation efficiency compared with the three-dimensional dynamic time-history analysis.

[0017] The specific embodiment of the present invention realizes the integrated overall consideration of the subway vehicle depot and the surface structure group above the cover, and proposes an efficient modeling method of the structural model introduced based on BIM and other means. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The following is the overall flow chart; Figure 2 Examples of spatial irregular spectrum curves of each characteristic cross section under different factors; Figure 3 It is the spectrum curve diagram of the interaction between structures under different factors; Figure 4 Schematic diagram of the shaking table test for soil, vehicle depot, platform, and cover structure group. DETAILED DESCRIPTION

[0019] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation mode, structure, characteristics and effects of the present invention are described in detail below in combination with the accompanying drawings and preferred embodiments.

[0020] Reference Figure 1 As shown, a simplified analysis method for the overall seismic response of a subway depot, platform and cover structure of the present invention comprises decomposing the overall three-dimensional model of the subway depot, platform and cover structure into soil, a three-dimensional model of the subway depot and a three-dimensional model of the platform and cover structure; 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 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 respectively, and establishing a spectrum curve of the influence of the cover structure on the seismic response of the depot and a spectrum curve of the influence of the seismic response of the subway depot on the cover structure. The specific embodiment of the present invention comprises 4 steps, specifically: Step 1: Overall modeling of the subway depot, soil, and surface structure and analysis of their seismic response. The model is a three-dimensional overall coupled calculation model, including: (1) Determination of calculation scope: The corresponding calculation scope is determined based on the Code for Seismic Design of Urban Rail Structures and the specific dimensions of the subway depot. The horizontal calculation width is generally 7 times 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 stratum.

[0021] (2) Establishment of calculation model: Based on the actual structural dimensions and soil calculation range, the corresponding code program is written based on the parametric design language of BIM or other software (examples are shown below), which can quickly realize the relative position relationship of different structures, thereby realizing an efficient modeling method for the overall model; global W_station = 80.0; Station width (m) global L_station = 400.0; Station length (m) global H_station = 12.0; Station height (m) global W_building = 120.0; surface structure width (m) global L_building = 100.0; Surface structure length (m) global H_building = 120.0; Surface structure height (m) global D_space = 10.0; Clearance between subway station and ground structure (m) global E_station = 35e9; station elastic modulus (Pa) global Density_station = 2500; Station density (kg / m3) (3) Meshing and unit type: The soil is discretized using 10-node tetrahedral units, and the above-ground and underground structures are discretized using structural units; (4) Constitutive model and calculation parameters: The Davidenkov equivalent linearization model is used for soil to consider the nonlinear characteristics of the soil, while the plastic damage model of concrete is used for the structure; (5) Contact treatment: The normal direction uses hard connection to avoid intrusion, and the tangential friction adopts the Coulomb model with a shear coefficient of 0.5; (6) Boundary conditions: Lateral binding boundaries are used, which means that 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; (7) Damping setting: The classic Rayleigh damping model is used, and the Rayleigh damping coefficient is determined by the system frequency calculation; (8) Dynamic time step: To ensure effective response to the propagation of ground motion, it is recommended that there should be at least 10 calculation steps within the time interval of ground motion recording (e.g., 0.02 s). Therefore, the dynamic time step can be set to 0.001 s or a smaller step generated by the system. However, the calculation efficiency should be considered to strike a balance between accuracy and efficiency. (9) Earthquake motion input: The computational model corresponding to a large underground structure is relatively large, and the spatial effect of earthquake motion cannot be ignored. This method uses the method of inputting earthquake motion in the bottom area of ​​the model to consider the traveling wave effect of seismic waves.

[0022] Step 2: Establishment of the first plane analysis model, including: (1) Select a subway depot cross section with typical characteristics, establish a corresponding two-dimensional plane analysis model, and calculate the seismic response of the structure. The underground structure seismic analysis method currently recommended by the "Urban Rail Transit Structure Seismic Design Code" is the plane response displacement method, but this method is only applicable to regular underground structures. Obviously, the response displacement method is not applicable to complex subway depot structures with spatial characteristics. The above method can transform complex spatial structure problems into simple plane problems; (2) Verify the rationality of the numerical method based on the completed subway depot shaking table test; (3) Use the verified numerical method to conduct numerical parameter analysis of key influencing factors of the full-scale subway depot, including: depot structure (size, burial depth, etc.), site soil (shear wave velocity, weak interlayer), seismic motion (seismic wave type, amplitude, consistency / inconsistency, etc.), to obtain the general seismic response law of the subway depot structure; (4) Compare and analyze the seismic responses of different characteristic sections with those of the actual subway depot, conduct a comprehensive analysis from the perspectives of structural acceleration, internal force, and deformation, and determine the spatial irregular spectrum curve of each characteristic section. Figure 2 Shown is one example; (5) Based on the determined irregular spectrum curve, a characteristic cross-section plane analysis model of the soil-subway depot is established taking into account the structural irregular characteristics.

[0023] Step 3: Establishment of the second plane analysis model, including: (1) For the cover structure group, three-dimensional analysis models of the platform-cover single structure and the platform-cover structure group were established respectively; (2) Use shaking table tests to verify the rationality of the numerical analysis method; (3) Based on the verified numerical analysis method, numerical parameter analysis of key influencing factors is carried out, including platform aspects (platform size, constraint conditions, etc.) and structural aspects (number of structures, structure height, structure spacing, structure type, etc.). The seismic response laws of a single structure and a group of structures are compared and analyzed, and the spectrum curves of each influencing factor are obtained respectively. Figure 3 As shown; (4) Based on the obtained spectral curve, a simplified plane analysis model of the platform-lid structure, namely the second plane analysis model, is established.

[0024] Step 4: Simplified seismic analysis of the subway depot and the structure above the cover, including: (1) Based on the first plane analysis model (simplified analysis model of soil and subway depot characteristic plane) and the second plane analysis model (simplified analysis model of platform and cover structure plane) established above, a plane overall analysis model (simplified plane overall analysis model of soil, subway depot, platform, and cover structure) was constructed, and its rationality was verified using the shaking table test results; (2) Compare and analyze the seismic response of the first plane analysis model and the plane overall analysis model, analyze the influence of the platform and the cover structure on the seismic response of the subway depot, and establish the influence spectrum curve of the cover structure on the seismic response of the depot based on numerical parameter analysis. Based on this, a simplified seismic analysis method for the subway depot considering the influence of the platform and the cover structure is established; (3) Compare and analyze the seismic response of the second plane model results with that of the overall plane analysis model, analyze the influence of the subway depot on the seismic response of the platform and the structure above the cover, and establish a spectrum curve of the influence of the subway depot on the seismic response of the structure above the cover based on numerical parameter analysis. Based on this, a simplified seismic analysis method for the platform and the structure above the cover that takes into account the influence of the subway depot is established.

[0025] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still 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; The seismic responses of the first plane analysis model, the second plane analysis model and the plane overall analysis model are compared and analyzed respectively, and the spectrum curve of the influence of the seismic response of the cover structure on the vehicle depot and the spectrum curve of the influence of the seismic response of the subway depot on the cover structure are established.

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: 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.

3. The simplified analysis method for the overall seismic response of a subway depot, platform and cover structure according to claim 2 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.

4. The simplified analysis method for the overall seismic response of a subway depot, platform and cover structure according to any one of claims 1 to 3, 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.

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: 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.

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: 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.

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: 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.

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: 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.

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 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.

10. The simplified analysis method for the overall seismic response of a subway depot, platform and cover structure according to claim 9, 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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