Seismic response calculation method for close-range crossed underground structure group and aseismic design process

Abstract

The invention discloses a close-range crossed underground structure group seismic response calculation method, provides a corresponding seismic design process, and determines main influence factors influencing system seismic response by establishing a calculation model containing a soil body-single typical underground structure and a soil body-close-range crossed underground structure group. And on the basis of numerical parameter analysis suggested influence factors, a complex interaction problem is simplified into a relatively mature anti-seismic analysis problem of a single typical underground structure, so that seismic response analysis and a practical anti-seismic design process of the close-range crossed underground structure group under the action of an earthquake are realized. The problem of aseismic design of a large number of emerging short-distance underground structure crossed structure groups at present is effectively solved.

Description

Technical Field

[0001] The present invention relates to the field of civil engineering earthquake resistance technology, and in particular to a method for calculating earthquake response of a close-range intersecting underground structure group and an earthquake resistance design process. Background Art

[0002] With the intensive development of urban underground space, underground projects inevitably have close crossings, and cross-shaped and X-shaped crossings are emerging. For example, in the Hongzhong section of Wuhan Metro Line 2 and Line 4, there are two lines and four tunnels with close overlapping tunnels, with a minimum clear spacing of only 1.3m ( Figure 1 ), which is much smaller than 1 times the tunnel diameter; in actual engineering cases such as the cross section of Beijing Subway Line 10 and Line 16 and the Shanghai Hongqiao Hub Underground Complex, the structural spacing is generally less than 1 times the structural size (0.5D-1D). These structures play an important role in the daily functions of the city, so it is urgent to study the seismic performance of close-range underground crossing structures. Under certain conditions, the seismic performance of a single underground structure can meet its own seismic requirements. However, with the addition of new underground structures, more soil-structure interfaces change the propagation of seismic waves, thereby changing the environment of the original single underground structure. The smaller the spacing, the greater the degree of change, and finally forms a complex interaction system of close-range underground crossing structures, in which there are interactions between the original underground structure and the new underground structure, and between the underground structure and the soil.

[0003] The current shortcomings are mainly reflected in the following aspects: 1) Insufficient basis for seismic design of intersection nodes: Currently, the design of underground intersection structures does not consider the impact of adjacent underground structures; 2) Computational efficiency bottleneck: When jointly analyzing a four-story underground transfer station and a tunnel group in Guangzhou, the ABAQUS model had more than 5×10^6 degrees of freedom, and a single time-history analysis took 240 hours, which could not meet the engineering iteration requirements.

[0004] 3) Three-dimensional wave field distortion: The shaking table test of Japanese scholar Kawashima showed that the two-dimensional model would underestimate the stress concentration effect at the cross node by 25%.

[0005] The 21st century is the century of urban underground space development and utilization. Urban underground space will be further developed and utilized on a large scale. The seismic performance of complex structures composed of close-range underground structures during earthquakes is crucial to the overall earthquake resistance and disaster prevention capabilities of the city. Its research is of great significance to improving the overall seismic performance and optimizing urban disaster prevention and mitigation strategies. Summary of the invention

[0006] In view of the shortcomings of the background technology, the technical problem to be solved by the present invention is to provide a method for calculating the seismic response of a group of closely intersecting underground structures and a seismic design process, which simplifies the complex interaction problem into a relatively mature seismic analysis problem of a single typical underground structure, realizes the seismic response analysis of a group of closely intersecting underground structures under earthquake action and a practical seismic design process, and effectively solves the seismic design problem of a large number of closely intersecting underground structure groups that are currently emerging.

[0007] To this end, the present invention is implemented by adopting the following technical solutions: The method for calculating the seismic response of a group of closely spaced intersecting underground structures is characterized by comprising the following steps: Step 1: Establish soil-single typical underground structure and soil-close-range cross-underground structure group calculation models; Step 2: Analyze the main influencing factors of the seismic response of soil-single typical underground structure and soil-close-distance cross-underground structure group, and verify the rationality of the calculation model of soil-single typical underground structure and soil-close-distance cross-underground structure group; Step 3: Simplified calculation method for the seismic response of soil-closely spaced intersecting underground structures: Based on the verified calculation model, numerical parameter analysis is carried out, and the range of values ​​of their respective influencing factors is determined by comparing with the seismic response of the corresponding soil-single typical underground structure.

[0008] Furthermore, the step 1 includes the following sub-steps: (1) Determination of calculation scope: Determine the corresponding calculation scope based on the Code for Seismic Design of Urban Rail Structures and the specific dimensions of the subway depot; (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 the software to establish the overall model; (3) Meshing and unit type: 10-node tetrahedron units are used for soil, and structural units are used for discretization of above-ground and underground structures; (4) Constitutive model and calculation parameters: The Davidenkov equivalent linearization model is used for soil to consider the nonlinear characteristics of the soil, and the plastic damage model of concrete is used for the structure; (5) Contact treatment: hard connection is used in the normal direction to avoid intrusion, and the Coulomb model is used in the tangential friction; (6) Boundary conditions: Lateral binding boundaries are used to ensure 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; (7) Damping setting: The Rayleigh damping model is adopted, and the Rayleigh damping coefficient is determined by the system frequency calculation; (9) Dynamic time step: There must be at least 10 calculation steps within the time interval of the ground motion recording; (10) Earthquake input: Input the selected earthquake time history curve at the bottom of the model, and consider different input directions and their combinations as required; Finally, a computational model is generated; Furthermore, the step 2 includes the following sub-steps: (1) Based on the completed shaking table test, taking the completed double tunnel under the subway station test condition as an example, the rationality of the soil-single typical underground structure and soil-close-distance cross-underground structure group calculation models are verified by comparing and analyzing the test data and numerical calculation results; (2) Based on numerical parameter analysis, the main influencing factors affecting the system are determined, including site soil, underground structure, and seismic motion.

[0009] Furthermore, in the sub-step (1), the lateral calculation width of the calculation range is 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 formation.

[0010] Furthermore, in the sub-step (2), the software is BIM, and the code program includes global W_station, i.e., station width (m), global L_station, i.e., station length (m), global H_station, i.e., station height (m), global D_tunnel, i.e., tunnel diameter (m), global D_space, i.e., the clear distance between the subway station and the tunnel (m), global E_structure, i.e., structural elastic modulus (Pa), global Density_structure, i.e., structural density (kg / m 3 ).

[0011] Furthermore, in the sub-step (2), the site soil aspect is the site soil type, which includes medium soft soil and medium hard soil, the soil equivalent shear wave velocity of the medium soft soil is less than or equal to 200m / s, and the soil equivalent shear wave velocity of the medium hard soil is greater than 200m / s, and the underground structure aspect includes the intersection angle φ Θ 、Structural clear spacing φ D 、Structural characteristic dimension φ L , the seismic aspects include seismic type φ T and the earthquake amplitude φ A .

[0012] Further, the value range of the impact factor calculated and analyzed in step 3 is as follows: .

[0013] Furthermore, the seismic response results of underground structures obtained by the simplified calculation method of the seismic response of soil-close-range crossing underground structure groups are compared with the shaking table test and the real three-dimensional time history analysis results to verify the rationality of the simplified method.

[0014] After adopting the above technical scheme, the present invention adopts the idea of ​​simplifying complex problems and transforming unknown problems into known problems, namely: calculating and analyzing the seismic response laws of complex underground cross-structures, determining the interaction influencing factors under different working conditions, and using these influencing factors to correct the existing seismic analysis method and seismic design process of a single typical underground structure, thereby establishing a seismic response analysis method and seismic design process for a complex, close-range cross-underground structure group.

[0015] The present invention also discloses a seismic design process based on the above-mentioned seismic response calculation method of a close-range intersecting underground structure group, which is characterized by comprising the following steps: Step 1: If the project requires a single underground structure, it is designed according to existing specifications and the internal forces and deformations of the structure are calculated; Step 2: If the project requires a group of closely intersecting underground structures, determine the influencing factors of each factor based on the site soil type and the intersection angle φ Θ 、Structural clear spacing φ D 、Structural characteristic dimension φ L 、Ground motion type φ T and the earthquake amplitude φ A Take values ​​and calculate the internal forces and deformations of the structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The present invention has the following accompanying drawings: Figure 1 It is a structural schematic diagram of four closely overlapping tunnel groups in the Hongzhong section of Wuhan Metro in the background technology; Figure 2 It is the overall flow chart of the present invention; Figure 3 Schematic diagram of the calculation model established by the present invention, where (a) is the calculation model of 4 tunnels in close proximity, (b) is the calculation model of double tunnels passing under a subway station, and (c) is the intersection of tunnels (upper and lower parallel, 45 degrees, and 90 degrees intersection); Figure 4 Schematic diagram of the completed shaking table test of a close-range underground intersection structure group, where (a) is a schematic diagram of the shaking table test of a single tunnel and a double parallel tunnel, (b) is a schematic diagram of the shaking table test of an upper and lower parallel tunnel, and (c) is a shaking table test of a double tunnel passing under a subway station; Figure 5The figures are curve comparison diagrams of the numerical calculation results of the vibration table and the test data in the present invention, wherein (a) is a curve comparison diagram of the numerical calculation results of the surface and the test data, (b) is a curve comparison diagram of the numerical calculation results of the station and the test data, and (c) is a comparison of the numerical calculation results of the double shield tunnel under the subway station and the test data; Figure 6 This is a flow chart of the seismic design of a group of closely spaced intersecting underground structures in the present invention. DETAILED DESCRIPTION

[0017] 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.

[0018] Refer to the above attached Figure 2-5 As shown, the method for calculating the seismic response of a close-range intersecting underground structure group provided by the present invention is characterized by comprising the following steps: Step 1: Establish a soil-single typical underground structure and soil-close-range cross-underground structure group calculation model; Step 1 includes the following sub-steps: (1) Determination of calculation scope: Determine the corresponding calculation scope based on the Code for Seismic Design of Urban Rail Structures and the specific dimensions of the subway depot; (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 the software to establish the overall model; (3) Meshing and unit type: 10-node tetrahedron units are used for soil, and structural units are used for discretization of above-ground and underground structures; (4) Constitutive model and calculation parameters: The Davidenkov equivalent linearization model is used for soil to consider the nonlinear characteristics of the soil, and the plastic damage model of concrete is used for the structure; (5) Contact treatment: hard connection is used in the normal direction to avoid intrusion, and the Coulomb model is used in the tangential friction; (6) Boundary conditions: Lateral binding boundaries are used to ensure 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; (7) Damping setting: The Rayleigh damping model is adopted, and the Rayleigh damping coefficient is determined by the system frequency calculation; (8) Dynamic time step: There must be at least 10 calculation steps within the time interval of the ground motion recording; (9) Earthquake input: Input the selected earthquake time history curve at the bottom of the model, and consider different input directions and their combinations as required; (10) finally generate the computational model; In the sub-step (1), the lateral calculation width of the calculation range is 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 formation; In the sub-step (2), the software is BIM, and the code program includes global W_station, i.e., station width (m), global L_station, i.e., station length (m), global H_station, i.e., station height (m), global D_tunnel, i.e., tunnel diameter (m), global D_space, i.e., the clear distance between the subway station and the tunnel (m), global E_structure, i.e., structural elastic modulus (Pa), global Density_structure, i.e., structural density (kg / m 3 ), the code program example is as follows: 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 D_tunnel = 12.0 ; tunnel diameter (m) global D_space = 1.0 ; Clearance between subway station and tunnel (m) global E_structure = 35e9 ; structural elastic modulus (Pa) global Density_structure = 2500 ; Structure density (kg / m3).

[0019] Step 2: Analyze the main influencing factors of the seismic response of soil-single typical underground structure and soil-close-distance cross-underground structure group, and verify the rationality of the calculation model of soil-single typical underground structure and soil-close-distance cross-underground structure group; Step 2 includes the following sub-steps: (1) Based on the completed shaking table test, taking the completed double tunnel under the subway station test condition as an example, the rationality of the soil-single typical underground structure and soil-close-distance cross-underground structure group calculation models are verified by comparing and analyzing the test data and numerical calculation results; (2) Determine the main influencing factors of the system based on numerical parameter analysis, including site soil, underground structure, and seismic motion; The site soil in the sub-step (2) is the site soil type, which includes medium soft soil and medium hard soil. The soil equivalent shear wave velocity of the medium soft soil is less than or equal to 200 m / s, and the soil equivalent shear wave velocity of the medium hard soil is greater than 200 m / s. The underground structure includes the intersection angle φ Θ 、Structural clear spacing φ D 、Structural characteristic dimension φ L , the seismic aspects include seismic type φ T and the earthquake amplitude φ A .

[0020] Step 3: Simplified calculation method for the seismic response of soil-closely spaced intersecting underground structures: Based on the verified calculation model, numerical parameter analysis is carried out, and the range of influencing factors is determined by comparing the seismic response of the corresponding soil-single typical underground structure; The impact factor values ​​calculated and analyzed in step 3 are as follows: ; The seismic response results of underground structures obtained by the simplified calculation method of the seismic response of soil-close-range crossing underground structure groups are compared with the results of shaking table tests and real three-dimensional time history analysis to verify the rationality of the simplified method.

[0021] The present invention also provides a seismic design process based on the above-mentioned method for calculating the seismic response of a close-range intersecting underground structure group, which is characterized by comprising the following steps: Step 1: If the project requires a single underground structure, it is designed according to existing specifications and the internal forces and deformations of the structure are calculated; Step 2: If the project requires a group of closely intersecting underground structures, determine the influencing factors of each factor based on the site soil type and the intersection angle φ Θ 、Structural clear spacing φ D 、Structural characteristic dimension φ L 、Ground motion type φ T and the earthquake amplitude φ A Take values ​​and calculate the internal forces and deformations of the structure.

[0022] In the present invention, by establishing a calculation model including soil-single typical underground structure and soil-close-range intersecting underground structure group, the main influencing factors affecting the seismic response of the system are determined, and the influencing factors are suggested based on numerical parameter analysis. The complex interaction problem is simplified into a relatively mature seismic analysis problem of a single typical underground structure, and the seismic response analysis of the close-range intersecting underground structure group under earthquake action and a practical seismic design process are realized, which effectively solves the seismic design problem of a large number of close-range intersecting structure groups that are currently emerging.

[0023] 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 method for calculating the seismic response of a group of closely spaced intersecting underground structures, characterized by: The following steps are involved: Step 1: Establish soil-single typical underground structure and soil-close-range cross-underground structure group calculation models; Step 2: Analyze the main influencing factors of the seismic response of soil-single typical underground structure and soil-close-distance cross-underground structure group, and verify the rationality of the calculation model of soil-single typical underground structure and soil-close-distance cross-underground structure group; Step 3: Simplified calculation method for the seismic response of soil-closely spaced intersecting underground structures: Based on the verified calculation model, numerical parameter analysis is carried out, and the range of values ​​of their respective influencing factors is determined by comparing with the seismic response of the corresponding soil-single typical underground structure.

2. The method for calculating seismic response of a group of closely spaced intersecting underground structures according to claim 1 is characterized by: The step 1 includes the following sub-steps: (1) Determination of calculation scope: Determine the corresponding calculation scope based on the Code for Seismic Design of Urban Rail Structures and the specific dimensions of the subway depot; (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 the software to establish the overall model; (3) Meshing and unit type: 10-node tetrahedron units are used for soil, and structural units are used for discretization of above-ground and underground structures; (4) Constitutive model and calculation parameters: The Davidenkov equivalent linearization model is used for soil to consider the nonlinear characteristics of the soil, and the plastic damage model of concrete is used for the structure; (5) Contact treatment: hard connection is used in the normal direction to avoid intrusion, and the Coulomb model is used in the tangential friction; (6) Boundary conditions: Lateral binding boundaries are used to ensure 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; (7) Damping setting: The Rayleigh damping model is adopted, and the Rayleigh damping coefficient is determined by the system frequency calculation; (8) Dynamic time step: There must be at least 10 calculation steps within the time interval of the ground motion recording; (9) Earthquake input: Input the selected earthquake time history curve at the bottom of the model, and consider different input directions and their combinations as required; (10) Finally, the computational model is generated.

3. The method for calculating seismic response of a group of closely spaced intersecting underground structures according to claim 1 is characterized by: The step 2 includes the following sub-steps: (1) Based on the completed shaking table test, taking the completed double tunnel under the subway station test condition as an example, the rationality of the soil-single typical underground structure and soil-close-distance cross-underground structure group calculation models are verified by comparing and analyzing the test data and numerical calculation results; (2) Based on numerical parameter analysis, the main influencing factors affecting the system are determined, including site soil, underground structure, and seismic motion.

4. The method for calculating seismic response of a group of closely spaced intersecting underground structures according to claim 2 is characterized by: In the sub-step (1), the lateral calculation width of the calculation range is 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 formation.

5. The method for calculating seismic response of a group of closely spaced intersecting underground structures according to claim 2 is characterized by: In the sub-step (2), the software is BIM, and the code program includes global W_station, i.e., station width (m), global L_station, i.e., station length (m), global H_station, i.e., station height (m), global D_tunnel, i.e., tunnel diameter (m), global D_space, i.e., the clear distance between the subway station and the tunnel (m), global E_structure, i.e., structural elastic modulus (Pa), global Density_structure, i.e., structural density (kg / m 3 ).

6. The method for calculating seismic response of a group of closely spaced intersecting underground structures according to claim 3 is characterized by: The site soil in the sub-step (2) is the site soil type, which includes medium soft soil and medium hard soil. The soil equivalent shear wave velocity of the medium soft soil is less than or equal to 200 m / s, and the soil equivalent shear wave velocity of the medium hard soil is greater than 200 m / s. The underground structure includes the intersection angle φ Θ 、Structural clear spacing φ D 、Structural characteristic dimension φ L , the seismic aspects include seismic type φ T and the earthquake amplitude φ A .

7. The method for calculating seismic response of a group of closely spaced intersecting underground structures according to claim 1 is characterized by: The value range of the impact factor calculated and analyzed in step 3 is as follows: 。 8. The method for calculating seismic response of a group of closely spaced intersecting underground structures according to claim 7 is characterized by: The seismic response results of underground structures obtained by the simplified calculation method of the seismic response of soil-close-range crossing underground structure groups are compared with the results of shaking table tests and real three-dimensional time history analysis to verify the rationality of the simplified method.

9. The seismic design process of the seismic response calculation method for a group of closely spaced intersecting underground structures according to claims 1 to 8 is characterized by: The following steps are involved: Step 1: If the project requires a single underground structure, it is designed according to existing specifications and the internal forces and deformations of the structure are calculated; Step 2: If the project requires a group of closely intersecting underground structures, determine the influencing factors of each factor based on the site soil type and the intersection angle φ Θ 、Structural clear spacing φ D 、Structural characteristic dimension φ L 、Ground motion type φ T and the earthquake amplitude φ A Take values ​​and calculate the internal forces and deformations of the structure.

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