Method for calculating earthquake action of rebuilt underground structure by considering influence of soil body

Abstract

The invention provides a method for calculating the seismic action of a rebuilt underground structure considering the influence of a soil body, and the method comprises the steps: building an overall calculation model comprising an overground structure and an underground structure, and simulating the rigidity relation between the soil body and a bottom plate of the underground structure, and the rigidity relation between the soil body and an outer wall of the underground structure; on the basis of an overall structure calculation model considering the rigidity of the foundation and the soil body around the underground structure, response spectrum seismic analysis and response displacement method analysis of the underground structure are conducted respectively; and carrying out most unfavorable combined working condition superposition on components of the underground structure in the overall calculation model according to internal force calculated by response spectrum seismic analysis and a response displacement method, and carrying out aseismic design on the components. Through the configuration, through response spectrum earthquake analysis and response displacement method analysis, the interaction influence of the site soil body, the underground structure and the overground structure can be quickly and conveniently considered, and earthquake action calculation and aseismic design of the rebuilt underground structure are achieved.

Description

Technical Field

[0001] The present invention relates to the field of architectural design, and in particular to a method for calculating seismic effects on an integral structure including an underground structure, taking into account soil-structure interaction and based on response spectrum seismic analysis and a response displacement method. Background Art

[0002] Traditional seismic design emphasizes "above-ground, below-ground" over "below-ground." Underground structures are generally considered less vulnerable to earthquake damage, and so are considered separately. Above-ground structures are simplified and analyzed as if embedded in the ground floor, while seismic analysis of the underground structure is generally omitted. Irregular and complex underground structures can present significant weaknesses, leading to significant damage in earthquakes and making post-earthquake repairs difficult. Consequently, important structures such as subway stations require consideration of underground seismic design.

[0003] Conventional pure underground structures (i.e., single-building underground structures) are relatively simple, and simplified analysis methods such as the response displacement method and the response acceleration method can be used. However, the seismic response of underground structures with superstructures (i.e., complex underground structures) not only shares the characteristics of ordinary underground structures mentioned above, but is also affected by the aboveground structure. Aboveground structures generate significant inertial interactions during earthquakes, and these inertial interactions are related to the natural vibration characteristics of the structure. The inertial forces generated by the aboveground structure acting on the underground structure will cause its seismic response to differ from that of ordinary underground structures. Therefore, the influence of the aboveground structure on the underground structure cannot be ignored.

[0004] Regarding the seismic design of such underground structures, the "Standard for Seismic Design of Underground Structures" requires that the underground structure and above-ground buildings and structures be calculated as a whole for reconstructed underground structures. The standard's explanatory text also points out that reconstructed underground structures are significantly affected by the combined inertial effects of the above-ground portion and the dynamic interaction between the soil and the structure in the underground portion during earthquakes, and therefore require a comprehensive seismic design for both the above-ground and underground portions. However, due to the immaturity of relevant research, the standard does not specifically address general seismic design requirements, key seismic calculation points, or seismic mitigation measures.

[0005] For underground structures with superstructures, the soil-structure dynamic interaction can be calculated using a time-history analysis method that includes both the soil and the structure. This approach involves introducing a virtual boundary (called an artificial boundary) to truncate the infinite domain of the soil, extracting the underground structure and its surrounding soil to form a finite domain, and then using numerical methods such as finite element methods for simulation. However, due to the large number of model elements including the soil, the lengthy time-history analysis calculations, and the uncertainty associated with the seismic waves used in time-history analysis, time-history analysis methods that consider the interaction between soil and structure are currently difficult to directly apply to the design of complex structures.

[0006] In summary, for integral structures containing underground structures, the various seismic design methods currently used in engineering design cannot conveniently consider the interaction between site soil, underground structures, and above-ground structures. In particular, there is no practical method for calculating the seismic effects of rebuilt underground structures. Summary of the Invention

[0007] The purpose of the present invention is to provide a method for calculating the seismic effects of a rebuilt underground structure taking into account the influence of soil, so as to solve the problem that the current seismic analysis of a rebuilt underground structure with an upper building cannot conveniently consider the interaction between the site soil, underground structure and above-ground structure.

[0008] The present invention is a method for calculating the seismic action of a reconstructed underground structure taking into account the influence of soil mass and based on the response displacement method and the overall structural response spectrum seismic analysis, comprising:

[0009] Step 1: Establish an overall structural calculation model that takes into account the stiffness of the soil around the foundation and underground structure. The overall structural calculation model includes simulation of the above-ground structure, underground structure, loads on the above-ground structure and underground structure, and the stiffness constraint relationship of the soil on the underground structure.

[0010] The stiffness constraint relationship includes the longitudinal stiffness constraint relationship of the soil on the bottom plate of the underground structure and the transverse stiffness constraint relationship of the soil on the outer wall of the underground structure.

[0011] Step 2: Based on the overall structural calculation model, perform response spectrum seismic analysis to obtain the response spectrum seismic effects of the above-ground and underground structures.

[0012] Based on the overall structural calculation model, the underground structure is analyzed by the response displacement method to obtain the seismic action of the soil displacement of the underground structure.

[0013] Step 3: Superimpose the internal forces analyzed by response spectrum seismic analysis and response displacement method according to the most unfavorable combined working conditions to carry out seismic design of underground structure components.

[0014] Based on the above technical features: In step one, the structure-spring analysis model is used to simulate the stiffness constraint relationship. After the calculation model of the above-ground structure and the underground structure is established, vertical and horizontal three-way foundation springs are set under the underground structure, and horizontal soil springs that only compress but do not pull are set around the underground structure.

[0015] Based on the above technical features: In step 1, a soil-pile-structure integrated model is used to simulate the stiffness constraint relationship. After establishing the calculation models of the aboveground and underground structures, a finite element model of the pile foundation and layered soil is directly established below and around the underground structure. Based on step 1 above, when performing the response spectrum seismic analysis in step 2, only the weight and inertia of the aboveground and underground structures are considered; the weight of the pile foundation and soil is not considered.

[0016] Based on the above technical features: In the response spectrum seismic analysis in step 2, the response spectrum seismic analysis is performed using the seismic motion parameters at the ground position or the bottom position of the underground structure.

[0017] In summary, the method for calculating seismic effects on reconstructed underground structures proposed in the present invention includes: establishing calculation models of the above-ground and underground structures to simulate the stiffness relationships between the soil and the base plate of the underground structure, as well as the stiffness relationships between the soil and the exterior walls of the underground structure; performing response spectrum seismic analysis and response displacement method analysis of the underground structure based on the overall structural calculation model that considers the stiffness of the foundation and the soil surrounding the underground structure; and performing seismic design of the components of the underground structure in the overall calculation model by superimposing the most unfavorable combined working conditions based on the internal forces calculated using the response spectrum seismic analysis and the response displacement method.

[0018] Compared with the existing method of calculating complex seismic effects of the soil-pile foundation-structure overall model based on time-history analysis, this application can quickly and conveniently consider the interaction between the site soil, underground structure, and above-ground structure through response spectrum seismic analysis and response displacement method analysis, and realize the seismic effect calculation and seismic design of the reconstructed underground structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a step diagram of the present invention.

[0020] Figure 2 This is a schematic diagram of the overall calculation model for simulating soil constraint stiffness using foundation springs and soil springs in an embodiment of the present invention.

[0021] Figure 3 Schematic diagram of the overall calculation model including above-ground structure and underground structure in an embodiment of the present invention.

[0022] Among them, 1-Finite element model of ground structure, 2-Finite element model of underground structure, 3-Three-dimensional foundation spring, 4-Horizontal soil spring. DETAILED DESCRIPTION

[0023] To make the objects, advantages and features of the present invention more clear, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that the drawings are simplified and not drawn to scale, and are only used to facilitate and clearly illustrate the purpose of the embodiments of the present invention.

[0024] like Figure 1 As shown in the figure, a calculation method for seismic effects on reconstructed underground structures considering the influence of soil is proposed. Step 1: Establish an overall structural calculation model that considers the stiffness of the soil around the foundation and underground structure, including structural units and loads such as beams, columns, walls, and floor slabs of the above-ground and underground structures, and the stiffness constraint relationship of the soil on the underground structure.

[0025] The stiffness constraint relationship includes the longitudinal stiffness constraint relationship of the soil on the bottom plate of the underground structure and the transverse stiffness constraint relationship of the soil on the outer wall of the underground structure.

[0026] Step 2: Based on the overall structural calculation model that takes into account the stiffness of the soil around the foundation and the basement, a response spectrum seismic analysis is performed to obtain the response spectrum seismic effects of the above-ground structure and the underground structure.

[0027] Based on the overall structural calculation model that takes into account the stiffness of the soil around the foundation and the basement, the underground structure is analyzed using the reaction displacement method to obtain the seismic effect of the soil layer displacement of the underground structure.

[0028] Step 3: Perform seismic design of components of the underground structure in the overall structural calculation model by superimposing the internal forces analyzed by the response spectrum seismic analysis and the response displacement method according to the most unfavorable combined working condition.

[0029] The following is a detailed description based on two embodiments.

[0030] The first embodiment adopts a structure-spring analysis model, and uses foundation springs and soil springs to simulate the analysis model of soil constraint stiffness for calculation. This method can use finite element structural analysis software such as Sap2000, Yingjianke Software (YJK), ABAQUS, etc. to establish an overall calculation model. Figure 2 It includes a finite element model 1 of the above-ground structure and a finite element model 2 of the underground structure, wherein the beams and columns of the above-ground structure and the underground structure can be simulated by beam elements, and the walls and floor slabs can be simulated by shell elements. Figure 3 This is a simplified diagram of the calculation model for simulating soil constraint stiffness using foundation springs and soil springs. The foundation can be simulated using three-dimensional foundation springs 3 in the vertical and horizontal directions, and the soil around the underground structure is simulated using horizontal soil springs 4 that only compress but do not pull.

[0031] Both the above-ground structure and the underground structure are subject to the response spectrum seismic force, and the outer wall of the underground structure is subject to the water and soil pressure and soil displacement seismic force. Figure 3 The way Figure 2A three-way foundation spring 3 is set below the underground structure of the model, and a horizontal soil spring 4 is set at the outer wall. The above-mentioned overall calculation model is subjected to a response spectrum seismic analysis. The response spectrum seismic analysis can be performed using the seismic motion parameters at the ground position or the bottom surface position of the underground structure, so as to obtain the response spectrum seismic effects of the above-ground structure and the underground structure, and obtain the internal forces and deformations of the components of the structure. The above-mentioned overall calculation model is subjected to a response displacement method seismic analysis to obtain the seismic effects of the soil layer displacement of the underground structure, and obtain the internal forces and deformations of the components of the structure. Finally, the internal forces calculated by the response spectrum seismic analysis and the response displacement method are superimposed according to the most unfavorable combined working conditions to perform seismic design of the components. According to this method, the seismic response of the rebuilt underground structure considering the influence of the soil is the sum of the seismic effects caused by the inertia force of the overall structure (response spectrum method analysis) and the seismic effects of the soil layer displacement of the site (response displacement method analysis).

[0032] Another embodiment uses the soil-pile-structure overall model. This method can be calculated using finite element structural analysis software such as ABAQUS and GFE. Figure 2 After establishing computational models for the above-ground and underground structures, finite element models of the pile foundations and layered soil are constructed directly beneath and around the underground structure, forming a holistic soil-pile-foundation-structure model. This model simulates the stiffness relationships between the soil and the underground structure's base plate, as well as the stiffness relationships between the soil and the underground structure's exterior walls. This method avoids the simplification required for spring simulations and adjusts the soil constraint stiffness by setting soil parameters. A response spectrum seismic analysis is performed on this holistic computational model. This analysis can be performed using ground motion parameters at the surface or at the bottom of the underground structure to determine the response spectrum seismic effects of the above-ground and underground structures, and to determine the internal forces and deformations of the structural components. Since response spectrum analysis primarily focuses on the seismic response of the structure, it only considers the gravity and inertia of the above-ground and underground structures, ignoring the gravity of the pile foundations and soil. A response-displacement method seismic analysis is performed on this holistic computational model to determine the seismic effects of the soil layer displacements on the underground structure, and to determine the internal forces and deformations of the structural components. Finally, the internal forces calculated from the response spectrum seismic analysis and the response-displacement method are superimposed according to the most unfavorable combined load case for component seismic design.

[0033] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention. These improvements and substitutions should also be regarded as the scope of protection of the present invention.

Claims

1. A method for calculating the seismic action of a reconstructed underground structure taking into account the influence of soil, characterized in that: include: Step 1: Establish an overall structural calculation model that takes into account the stiffness of the soil surrounding the foundation and the underground structure. The overall structural calculation model includes a simulation of the above-ground structure, the underground structure, the loads on the above-ground structure and the underground structure, and the stiffness constraint relationship between the soil and the underground structure. The stiffness constraint relationship includes a longitudinal stiffness constraint relationship between the soil and the bottom plate of the underground structure and a transverse stiffness constraint relationship between the soil and the outer wall of the underground structure; Step 2: performing a response spectrum seismic analysis based on the overall structural calculation model to obtain the response spectrum seismic effects of the above-ground structure and the underground structure; Based on the overall structural calculation model, the reaction displacement method is performed on the underground structure to obtain the seismic effect of soil layer displacement of the underground structure; Step 3: Perform seismic design of components of the underground structure by superimposing the internal forces analyzed by the response spectrum seismic analysis and the response displacement method according to the most unfavorable combined working condition.

2. The method for calculating seismic action of a reconstructed underground structure considering soil influence according to claim 1, characterized in that: In the step 1, a structure-spring analysis model is used to simulate the stiffness constraint relationship. After the calculation models of the above-ground structure and the underground structure are established, vertical and horizontal three-dimensional foundation springs are set below the underground structure, and horizontal soil springs that only compress but do not pull are set around the underground structure.

3. The method for calculating seismic action of a reconstructed underground structure considering soil influence according to claim 1, characterized in that: In the step 1, the stiffness constraint relationship is simulated using a soil-pile foundation-structure overall model. After the calculation models of the above-ground structure and the underground structure are established, a finite element model of the pile foundation and the layered soil is established directly below and around the underground structure.

4. The method for calculating seismic action of a reconstructed underground structure considering soil influence according to claim 3, characterized in that: When performing the response spectrum seismic analysis in step 2, only the weight and inertial force of the above-ground structure and the underground structure are considered, and the weight of the pile foundation and the soil are not considered.

5. The method for calculating seismic action of a reconstructed underground structure considering soil influence according to claim 1, 2, 3 or 4, characterized in that: The response spectrum seismic analysis in step 2 is performed using earthquake motion parameters at the ground position or the bottom position of the underground structure.

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