CN112632837B - Method for determining longitudinal earthquake-resistant numerical value of underground structure - Google Patents
Method for determining longitudinal earthquake-resistant numerical value of underground structure Download PDFInfo
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Abstract
The invention provides a method for determining a longitudinal earthquake-resistant numerical value of an underground structure, which adopts a sandy soil liquefaction structure to assign values to soil layer materials, completes the conversion of the sandy soil liquefaction structure from theory to practical application, realizes the combination of three-dimensional free field nonlinear earthquake effect analysis and underground structure longitudinal shell-spring model earthquake-resistant analysis, and achieves soil spring displacement time course assignment by traversing the underground structure cross section displacement time course extraction of a three-dimensional free field, thereby obtaining the underground structure longitudinal earthquake-resistant numerical value.
Description
Technical Field
The invention relates to a method for determining a longitudinal anti-seismic numerical value of an underground structure, and belongs to the technical field of shield tunnel anti-seismic measure research.
Background
With the development of the economy and the improvement of the comprehensive national force of China, the development speed of underground engineering of large and medium cities is increased, and the development of tunnel construction scale of China is more rapid. Many of these tunnels are located in strong earthquake areas, once strong earthquake occurs, the safe operation of the tunnels is seriously threatened, and serious casualties and huge economic losses are caused, so that the research on the earthquake response characteristics of the underground tunnels under the action of the strong earthquake is particularly important.
In order to solve the problem of longitudinal earthquake reaction of a large shield tunnel under the action of strong earthquake, scholars at home and abroad construct various models for research.
Miao Yu et al, and the like, discloses a method for analyzing longitudinal earthquake response of a shield tunnel for growing on the sea floor by calculating a longitudinal beam-spring model, wherein a two-dimensional free field numerical model is established, displacement time-course responses of corresponding pipe ring middle points at tunnel positions are extracted, a series of displacement time-course responses are input into a foundation spring fixed end, and the longitudinal earthquake response of the shield tunnel for growing on the sea floor is analyzed by calculating the longitudinal beam-spring model, so that the opening amount between the pipe rings is studied. Due to the limitation of a two-dimensional free field numerical model, three-dimensional parameters of a soil body spring cannot be completely extracted, multidirectional displacement response around a tunnel cannot be extracted in a self-defined mode, and geometric non-uniformity of a soil body three-dimensional space cannot be considered. The constitutive model adopted in the paper is only a total stress method, the influence of soil liquefaction cannot be considered by the constitutive model, meanwhile, the local detail stress condition of the structure cannot be observed by the beam-spring model, the pipe rings are difficult to connect with springs and soil spring coefficients, the longitudinal length of the shield tunnel is long, the penetrating stratum is complex, the longitudinal pipe rings are connected through a large number of bolts, the discontinuity of the rigidity of the tunnel structure is large, and therefore the integral rigidity and deformation characteristics of the pipe rings cannot be fully reflected by the existing long and large underground structure earthquake-resistant calculation theory.
For the above reasons, the longitudinal seismic direction still has the value of continuing the deep research.
Disclosure of Invention
In order to solve the defects of the prior art, the invention provides a method for determining the longitudinal earthquake-resistant value of an underground structure, which adopts a sand liquefaction structure to assign values to soil layer material parameters, completes the conversion of the sand liquefaction structure from theory to practical application, realizes the combination of three-dimensional free field nonlinear earthquake effect analysis and underground structure longitudinal shell-spring model earthquake-resistant analysis, thereby obtaining the longitudinal earthquake-resistant value of the underground structure, truly reflecting the stress condition of the underground structure, not only calculating the annular section of a shield tunnel type, but also calculating the square section of a immersed tube and pipe gallery type, simultaneously assigning values in a mode of establishing a soil body model, truly reflecting the stress condition of the underground structure, and being widely applicable to the scene.
The invention adopts the technical proposal for solving the technical problems that: the method for determining the longitudinal earthquake resistance value of the underground structure comprises the following steps:
s1, analyzing a three-dimensional free field nonlinear seismic effect:
s1.1, extracting soil layer and/or rock stratum decomposition coordinate data according to a geological survey result;
S1.2, constructing a refined true three-dimensional free field model by utilizing soil layer and/or rock layer decomposition coordinate data;
s1.3, adopting a sandy soil liquefaction structure to assign values to soil layer material parameters in the refined true three-dimensional free field model;
s1.4, calculating a viscoelastic artificial boundary parameter, selecting bedrock earthquake, taking the viscoelastic boundary as a boundary condition, and applying earthquake motion consistency input or non-consistency input at the bedrock in the refined three-dimensional free field model;
s1.5, performing calculation on the refined true three-dimensional free field model to obtain an earthquake response analysis result;
s2, extracting a displacement time course passing through any selected interval of the position of the long and large underground structure in the refined three-dimensional free field model:
s2.1, setting a spacing distance, and extracting each coordinate of the cross section of the underground structure of the spacing distance;
S2.2, setting a precision parameter n, and extracting displacement time courses of n points around each coordinate of the cross section of the underground structure;
s3, earthquake resistance analysis of a longitudinal shell-spring model of the underground structure:
s3.1, extracting centroid coordinates of the cross section of the underground structure;
s3.2, constructing a three-dimensional shell-spring model, wherein soil springs are arranged at n points around the cross section of the underground structure in the three-dimensional shell-spring model;
S3.3, assigning the displacement time course obtained by calculating the three-dimensional free field in the step S2.2 to the other end of the soil spring;
And S3.4, calculating the three-dimensional shell-spring model to obtain a longitudinal earthquake reaction analysis result of the long and large underground structure.
The steps of extracting soil layer and/or rock layer decomposition coordinate data according to the geological exploration result in the step S1.1, extracting displacement time interval crossing any selected distance of the position of the long underground structure in the refined true three-dimensional free field model in the step S2, extracting cross section centroid coordinates of the underground structure in the step S3.1 and assigning displacement time interval in the step S3.4 are respectively realized through Python compiling.
The refined true three-dimensional free field model described in step S1.2 is built by the following procedure:
s1.2.1, defining nodes on the tunnel model axis;
s1.2.2 defining the units required by the tunnel model;
s1.2.3 defining material properties and interface properties;
s1.2.2 defining a constraint relationship between a node of the simulated joint portion and an endpoint of the pipe joint;
s1.2.2, assembling the components into a tunnel model for calculation and analysis.
The assignment of soil layer material parameters in the refined true three-dimensional free field model by adopting the sand liquefaction mechanism in the step S1.3 specifically comprises the following steps:
s1.3.1, adopting a nested yield surface hardening rule as a theoretical framework to improve the yield surface hardening rule in an elastoplastic constitutive model of an original stress-strain mixing space;
S1.3.2, replacing an original shear strain algorithm in an elastoplastic constitutive model of the original stress-strain hybrid space by adopting an optimized equivalent shear strain algorithm;
S1.3.3, developing a three-dimensional display sub-module of an elastoplastic constitutive model of a stress-strain mixing space after S1.3.1 and 1.3.2 improvement based on an ABAQUS explicit module (VUMAT), obtaining a sandy soil liquefaction constitutive, and carrying out soil layer material parameter assignment;
And S2, the position of the long and large underground structure comprises the periphery of the cross section and the longitudinal range of the long and large underground structure.
The step S2.1 is to set the interval distance, extract each coordinate of the cross section of the underground structure of the interval distance, and realize the following steps:
s2.1.1, calculating to obtain free field data, and converting coordinates in the free field data into tuples for storage;
s2.1.2 defining a path through the index tuple;
s2.1.3, setting a field variable to be output;
s2.1.4 repeating steps S2.1.2 and S2.1.3, extracting field variables at different time steps under different paths, and storing the values of the extracted field variables into new tuples;
s2.1.5, after the interval distance is set, inquiring corresponding coordinates in the new tuple to realize extraction.
The construction of the three-dimensional shell-spring model in the step S3.2 specifically comprises the following steps:
S3.2.1, simulating a tunnel duct piece by utilizing a pipe joint shell unit, wherein radial earth springs are arranged on the outer surfaces of the pipe joint shell units, multipoint constraint control points are arranged between adjacent pipe annular shell units, pipe joint springs are arranged between the multipoint constraint control points to simulate joint bolts, and each pipe joint spring comprises a pipe joint axial spring, a pipe joint rotating spring and a pipe joint shearing spring;
s3.2.2, a radial compressive stiffness and two tangential shear stiffness of the earth spring are calculated by the following formulas:
Kt＝3G
K1＝βKt
Wherein K t represents the spring coefficient of foundation soil in tangential unit length, K 1 represents the spring coefficient of foundation soil in radial unit length, G represents the shear modulus of foundation soil corresponding to the maximum strain amplitude of earthquake vibration, and beta represents the conversion coefficient;
S3.2.3 calculating the parameters of the internode springs through a model.
The invention has the beneficial effects based on the technical scheme that:
(1) According to the method for determining the longitudinal earthquake-resistant value of the underground structure, provided by the invention, the three-dimensional free field nonlinear earthquake effect analysis is combined with the underground structure longitudinal shell-spring model earthquake-resistant analysis, and the earth spring displacement time course assignment is realized through the underground structure cross section displacement time course extraction passing through the three-dimensional free field, so that the underground structure longitudinal earthquake-resistant value is obtained;
(2) Compared with the traditional two-dimensional model, the refined true three-dimensional free field model in the method for determining the longitudinal earthquake-resistant numerical value of the underground structure can consider the space geometric effect, and the calculation result is more consistent with the actual numerical value;
(3) According to the method for determining the longitudinal earthquake-resistant numerical value of the underground structure, the soil layer material parameter is assigned by adopting the sandy soil liquefaction structure, although students such as Yang, ahmed and the like provide theoretical basis for the model, the following technical difficulties still exist in practical application: the problem of overlarge state variable memory quantity when large three-dimensional finite element numerical calculation is performed, the calculation efficiency and precision are low when numerical analysis is performed, and explicit secondary development is not performed by someone yet; the invention adopts the nested yield surface hardening rule as a theoretical frame to improve the original yield surface hardening rule so as to solve the problem of calculation overflow error reporting caused by overlarge state variable memory quantity when large three-dimensional numerical calculation is performed, adopts a new optimized equivalent shear strain algorithm to solve the problems of numerical calculation efficiency and result precision, and utilizes an ABAQUS display module to develop a three-dimensional display subroutine module of the constitutive model so as to be suitable for analyzing the three-dimensional (including two-dimensional) soil nonlinearity problem;
(4) The method for determining the longitudinal earthquake-resistant numerical value of the underground structure provided by the invention simulates the tunnel structure by using a refined true three-dimensional free site model, adopts a combination form of multipoint constraint control points and springs, has rich forms of pipe joint shell units, can be used for calculating the annular section of the shield tunnel type, can also be used for calculating the square section of the immersed pipe and pipe gallery type, can be used for assigning values in a mode of establishing a soil body model, can truly reflect the stress condition of the underground structure, and is widely applicable to scenes.
Drawings
FIG. 1 is a flow chart of a method for determining the longitudinal earthquake resistance value of an underground structure.
Fig. 2 is a schematic diagram of a pipe joint shell unit model, wherein fig. 2 (a) is a schematic diagram of multi-point constraint connection of a tunnel pipe ring, fig. 2 (b) is a schematic diagram of multi-point constraint connection of a pipe gallery pipe ring, and fig. 2 (c) is a schematic diagram of connection of adjacent multi-point constraint control points.
Fig. 3 is a schematic drawing of a tunnel segment deformed by pulling and pressing.
Fig. 4 is a drawing-pressing anisotropic nonlinear spring mechanism between tube rings.
Fig. 5 is a diagram of a rotating nonlinear spring mechanism between tube rings.
Fig. 6 is a stress-strain diagram of the connecting bolt in an elastic state.
In the figure, a 1-finite element grid, 2-multi-point constraint control points, 3-constraint reference points and 4-tube inter-joint springs.
Detailed Description
The invention is further described below with reference to the drawings and examples.
Referring to fig. 1, a method for determining the longitudinal earthquake resistance value of an underground structure is provided, which comprises the following steps:
s1, analyzing a three-dimensional free field nonlinear seismic effect:
s1.1, extracting soil layer and/or rock stratum decomposition coordinate data according to a geological survey result;
s1.2, constructing a refined true three-dimensional free field model by utilizing soil layer and/or rock layer decomposition coordinate data; the refined true three-dimensional free field model is established through the following processes:
S1.2.1, defining nodes on the axes of the immersed tube tunnel model;
s1.2.2 defining units required by the immersed tube tunnel model;
s1.2.3 defining material properties and interface properties;
s1.2.2 defining a constraint relationship between a node of the simulated joint portion and an endpoint of the pipe joint;
S1.2.2, assembling the components into a immersed tube tunnel model for calculation and analysis;
s1.3, adopting a sandy soil liquefaction structure to assign values to soil layer material parameters in the refined true three-dimensional free field model;
in this embodiment, the sand liquefaction mechanism is improved on the basis of the elastoplastic constitutive model of the traditional stress-strain mixing space. As the students such as Yang and Ahmed only provide theoretical basis, the practical application still has the technical difficulties of overlarge state variable memory quantity when carrying out large-scale three-dimensional finite element numerical calculation, lower calculation efficiency and precision when carrying out numerical analysis, explicit secondary development and the like, the following process is adopted to develop the sandy soil liquefaction structure, and then the sandy soil liquefaction structure is embedded into ABAQUS finite element software:
s1.3.1, adopting a nested yield surface hardening rule as a theoretical framework to improve the yield surface hardening rule in an elastoplastic constitutive model of an original stress-strain mixing space;
S1.3.2, replacing an original shear strain algorithm in an elastoplastic constitutive model of the original stress-strain hybrid space by adopting an optimized equivalent shear strain algorithm;
s1.3.3, developing a three-dimensional display sub-module of an elastoplastic constitutive model of a stress-strain mixing space after S1.3.1 and 1.3.2 improvement based on an ABAQUS display module, obtaining a sandy soil liquefaction constitutive, and carrying out coating material parameter assignment;
Through the steps, the influence of soil liquefaction can be calculated, so that the calculated result is more approximate to a true value;
S1.4, calculating a viscoelastic artificial boundary parameter, selecting bedrock earthquake, taking the viscoelastic convenience as a boundary condition, and applying earthquake motion consistency input or non-consistency input at the bedrock in the refined three-dimensional free field model;
the data source of the bedrock ground vibration is a Japanese kik-net database;
S1.5, performing calculation on the refined true three-dimensional free field model to obtain a seismic effect analysis result;
S2, extracting a displacement time interval of any selected interval passing through the position of the long and large underground structure (comprising the periphery of the cross section and the longitudinal range of the long and large underground structure) in the refined three-dimensional free field model:
S2.1, setting a fixed distance, and extracting each coordinate of the cross section of the underground structure at fixed intervals;
In the existing processing mode, a preset observation point is needed when a model planning grid is just started to be established, and fixed interval distance displacement is required to be set, so that the technical requirement on grid division is very high, and even the three-dimensional non-uniform site modeling cannot be realized at all; the modeling in the mode is completed, the interval distance of the follow-up extracted data cannot be changed, and the original free field cannot be reused when other models are analyzed;
To solve this problem, the present embodiment implements an extraction process by:
S2.1.1, calculating to obtain a free field data odb file, and converting coordinates in the odb file into tuples for storage;
s2.1.2, running a python script, defining a path (path) in a visualization module (visualization) through an index tuple, and presetting a coordinate value excel file to be extracted;
s2.1.3, setting a field variable to be output;
S2.1.4 repeating steps S2.1.2 and S2.1.3 by a for loop, extracting field variables at different time steps under different paths, storing the values of the extracted field variables into new tuples, and writing the results into an excel document;
S2.1.5, after setting the interval distance, inquiring corresponding coordinates in the new tuple to realize extraction;
Through the processing of the steps, the problem of grid division is not needed to be considered in the data extraction, so that the grid division time is greatly saved, the problem of building and calculating a free site model is not needed in the subsequent analysis of other long and large underground structures, and the calculation resources and time are also saved;
Taking the establishment of a three-dimensional free field model of 6km multiplied by 0.3km multiplied by 0.1km as an example, the establishment of the three-dimensional nonuniform free field model requiring a preset observation point by using the existing method takes more than 20 hours, and the modeling only takes about 10 hours after the preset point is removed; the data extraction time is also greatly reduced, the original tunnel data extraction time with 6km length needs 3 hours, and the processing process can be shortened to 30 minutes by adopting the embodiment;
S2.2, setting a precision parameter n, and extracting displacement time courses of n points around each coordinate of the cross section of the underground structure;
s3, earthquake resistance analysis of a longitudinal shell-spring model of the underground structure:
s3.1, extracting centroid coordinates of the cross section of the underground structure;
s3.2, constructing a three-dimensional shell-spring model, wherein soil springs are arranged at n points around the cross section of the underground structure in the three-dimensional shell-spring model; the construction of the three-dimensional shell-spring model specifically comprises the following steps:
S3.2.1, referring to fig. 2, simulating a tunnel segment by using pipe segment shell units, wherein the pipe segment shell units can be realized by finite element grids 1, constraint reference points 3 are arranged on each finite element grid so as to facilitate display and operation in a system, radial earth springs are arranged on the outer surfaces of the pipe segment shell units, multipoint constraint control points 2 are arranged between adjacent pipe annular shell units, pipe segment springs 4 are arranged between the multipoint constraint control points so as to simulate joint bolts, and each pipe segment spring comprises a pipe segment joint axial spring, a pipe segment joint rotating spring and a pipe segment joint shearing spring;
the model establishment can be selected according to the actual underground structure, and the pipe joint shell unit can be arranged into a ring shape shown in the figure 2 (a) and is used for calculating circular section structures such as shield tunnels; the device can also be set to be square as shown in fig. 2 (b) and used for calculating square cross-section structures such as immersed tubes, tube galleries and the like;
s3.2.2, a radial compressive stiffness and two tangential shear stiffness of the earth spring are calculated by the following formulas:
Kt＝3G (1)
K1＝βKt (2)
Wherein K t represents the spring coefficient of foundation soil in tangential unit length, K 1 represents the spring coefficient of foundation soil in radial unit length, G represents the shear modulus of foundation soil corresponding to the maximum strain amplitude of earthquake vibration, and beta represents the conversion coefficient;
s3.2.3 calculating parameters of the internode springs through a model:
S3.2.3.1, axial spring between pipe joints:
referring to fig. 3, when the tunnel shield segment is pulled, the axial tensile stiffness of the joint is taken as the sum of the stiffness of each connecting bolt; when the pipe ring is pressed, only the pipe section is pressed, and the connecting bolt is not stressed any more, and the axial compressive rigidity of the joint can be regarded as the compressive rigidity of the pipe section. The longitudinal joint can be simulated into a nonlinear spring with different tension and compression performances according to the elastoplastic stress characteristics of the bolts at the joint.
The model shows that the axial spring stiffness K u between the pipe joints can be calculated according to the following sections of the atmosphere in the stress stage, wherein the compression stiffness is as follows:
Wherein E c is the elastic modulus of the concrete, A c is the cross-sectional area of the pipe ring, and l s is the length of the pipe ring;
The tensile elastic stiffness is:
Ku1＝nks1 (4)
The post-yield stiffness is:
Ku2＝nks2 (6)
Wherein n is the number of bolts, k s1 is the elastic rigidity of a single bolt, k s2 is the rigidity after the single bolt is yielded, l is the length of the bolt, A s is the cross-sectional area of the bolt, E s is the elastic modulus of the bolt, and alpha is the elastic rigidity ratio;
The elastic limit tensile force of the joint is as follows:
Ny＝nAs(fy-P) (8)
the corresponding elastic modulus limit deformation is:
The ultimate tensile force of the joint is as follows:
Nm＝nAs(fm-P) (10)
the corresponding limit deformations are:
Wherein f y is the bolt yield stress, f m is the bolt limit stress, and P is the bolt prestress;
s3.2.3.2, a joint connection rotary spring:
Referring to fig. 5, when the joint between the rings is bent, the connecting bolts bear tensile stress in the tension zone, and the pipe section concrete singly bears compressive stress in the compression zone, so that the pipe section concrete stress is always in an elastic state; the cross-sectional deformation conforms to the flat cross-section and small deformation assumptions. When the joint bolt is fully elastic, the stress and deformation conditions are as shown in FIG. 6, x, The position and angle of the neutral axis, respectively, wherein
The deformation of the tension zone only contains the deformation of the joint bolts and does not contain the tension deformation of the concrete, which is different from the equivalent continuous beam model, because the joint and the pipe ring are considered respectively in the calculation process of the model, and therefore, the deformation of the bolts between the rings only needs to be reacted in the tension zone when the rotational rigidity of the joint is calculated.
The deformation coordination conditions of the joint are as follows:
Wherein epsilon c is compressive strain of concrete at the edge of the pipe ring, theta is a joint corner, D is the outer diameter of the pipe ring, r is the average value of the inner and outer radii of the pipe ring, and delta j is the maximum opening amount of the joint of the pipe ring;
the joint force balance conditions are:
Wherein t is the thickness of the pipe ring, k r is the linear stiffness of the tensile spring between the rings, and k r＝Ku1/(2pi r) or k u2/(2pi r);
substitution of the formulae (12) to (14) into the formula (15) can be obtained:
Wherein the method comprises the steps of
According to the deformation coordination condition and the force balance condition, the bending stiffness expression of the joint is as follows:
The yield bending moment is:
The ultimate bending moment is:
Wherein K θ1 represents the bending stiffness of the joint in the first deformation range segment 1-theta y, and K θ2 represents the bending stiffness of the joint in the first deformation range segment theta y～θm.
S3.2.3.3, the joint-to-joint shearing spring can be assumed to be infinite;
S3.3, assigning the displacement time course obtained by calculating the three-dimensional free field in the step S2.2 to the other end of the soil spring;
And S3.4, calculating the three-dimensional shell-spring model to obtain a longitudinal earthquake reaction analysis result of the long and large underground structure.
The steps of extracting soil layer and/or rock layer decomposition coordinate data according to the geological exploration result in the step S1.1, extracting displacement time interval crossing any selected distance of the position of the long underground structure in the refined true three-dimensional free field model in the step S2, extracting cross section centroid coordinates of the underground structure in the step S3.1 and assigning displacement time interval in the step S3.4 are respectively realized through Python compiling.
In order to verify the advancement of the present invention, a simulation experiment comparison was performed using a conventional beam-spring model as a control group:
The 3D fine time-course analysis method is generally considered to be a relatively accurate analysis method, but because of its high algorithm complexity and high time consumption, the practical application is limited, and is generally used as an evaluation standard. The earthquake waves under five working conditions are selected to be respectively substituted into a 3D refined model, a beam-spring model and the complete model provided by the invention to calculate the opening amount between loops, the opening amount between loops is used as equivalent data of the longitudinal earthquake resistance value of the underground structure, and the result obtained by calculating the 3D refined model is used as a benchmark to respectively calculate errors of the beam-spring model and the complete model provided by the invention, so that the following data can be obtained:
TABLE 1 peak contrast between-Loop joint opening amounts under different analytical models
As can be seen from the comparison, the error of the opening amount between the rings calculated by the method for determining the longitudinal earthquake resistance value of the underground structure is obviously smaller than the calculation result of the traditional beam spring model, is quite close to a 3D refined model, and even the error amount between the method and the 3D refined model is only 8.08% under the condition of selecting certain earthquake waves. Due to the operability of the method, the method is better in practicability compared with a 3D refined model, and the longitudinal seismic response of the underground tunnel can be studied through segmentation calculation.
The invention provides a method for determining a longitudinal earthquake-resistant numerical value of an underground structure, which adopts a sandy soil liquefaction structure to assign values to soil layer materials, completes the conversion of the sandy soil liquefaction structure from theory to practical application, realizes the combination of three-dimensional free field nonlinear earthquake effect analysis and underground structure longitudinal shell-spring model earthquake-resistant analysis, and achieves soil spring displacement time course assignment by traversing the underground structure cross section displacement time course extraction of a three-dimensional free field, thereby obtaining the underground structure longitudinal earthquake-resistant numerical value.
Claims (7)
1. The method for determining the longitudinal earthquake-resistant numerical value of the underground structure is characterized by comprising the following steps of:
s1, analyzing a three-dimensional free field nonlinear seismic effect:
s1.1, extracting soil layer and/or rock stratum decomposition coordinate data according to a geological survey result;
S1.2, constructing a refined true three-dimensional free field model by utilizing soil layer and/or rock layer decomposition coordinate data;
s1.3, adopting a sandy soil liquefaction structure to assign values to soil layer material parameters in the refined true three-dimensional free field model;
s1.4, calculating a viscoelastic artificial boundary parameter, selecting bedrock earthquake, taking the viscoelastic boundary as a boundary condition, and applying earthquake motion consistency input or non-consistency input at the bedrock in the refined three-dimensional free field model;
s1.5, performing calculation on the refined true three-dimensional free field model to obtain an earthquake response analysis result;
s2, extracting a displacement time course passing through any selected interval of the position of the long and large underground structure in the refined three-dimensional free field model:
s2.1, setting a spacing distance, and extracting each coordinate of the cross section of the underground structure of the spacing distance;
S2.2, setting a precision parameter n, and extracting displacement time courses of n points around each coordinate of the cross section of the underground structure;
s3, earthquake resistance analysis of a longitudinal shell-spring model of the underground structure:
s3.1, extracting centroid coordinates of the cross section of the underground structure;
s3.2, constructing a three-dimensional shell-spring model, wherein soil springs are arranged at n points around the cross section of the underground structure in the three-dimensional shell-spring model;
S3.3, assigning the displacement time course obtained by calculating the three-dimensional free field in the step S2.2 to the other end of the soil spring;
And S3.4, calculating the three-dimensional shell-spring model to obtain a longitudinal earthquake reaction analysis result of the long and large underground structure.
2. The method for determining the longitudinal seismic value of a subterranean structure according to claim 1, wherein: the steps of extracting soil layer and/or rock layer decomposition coordinate data according to the geological exploration result in the step S1.1, extracting displacement time interval crossing any selected distance of the position of the long underground structure in the refined true three-dimensional free field model in the step S2, extracting cross section centroid coordinates of the underground structure in the step S3.1 and assigning displacement time interval in the step S3.4 are respectively realized through Python compiling.
3. The method for determining the longitudinal seismic value of a subterranean structure according to claim 1, wherein: the refined true three-dimensional free field model described in step S1.2 is built by the following procedure:
s1.2.1, defining nodes on the tunnel model axis;
s1.2.2 defining the units required by the tunnel model;
s1.2.3 defining material properties and interface properties;
S1.2.4 defining a constraint relation between a node of the simulated joint part and a pipe joint end point;
S1.2.5, assembling the nodes on the axes of the tunnel model, units required by the tunnel model, the simulated joint parts and the pipe joints into the tunnel model for calculation and analysis.
4. The method for determining the longitudinal seismic value of a subterranean structure according to claim 1, wherein: the assignment of soil layer material parameters in the refined true three-dimensional free field model by adopting the sand liquefaction mechanism in the step S1.3 specifically comprises the following steps:
s1.3.1, adopting a nested yield surface hardening rule as a theoretical framework to improve the yield surface hardening rule in an elastoplastic constitutive model of an original stress-strain mixing space;
S1.3.2, replacing an original shear strain algorithm in an elastoplastic constitutive model of the original stress-strain hybrid space by adopting an optimized equivalent shear strain algorithm;
S1.3.3, developing a three-dimensional display sub-module of an elastoplastic constitutive model of a stress-strain mixing space after S1.3.1 and 1.3.2 improvement based on an ABAQUS display module, obtaining a sandy soil liquefaction constitutive, and carrying out soil layer material parameter assignment.
5. The method for determining the longitudinal seismic value of a subterranean structure according to claim 1, wherein: and S2, the position of the long and large underground structure comprises the periphery of the cross section and the longitudinal range of the long and large underground structure.
6. The method for determining the longitudinal seismic value of a subterranean structure according to claim 1, wherein: the step S2.1 is to set the interval distance, extract each coordinate of the cross section of the underground structure of the interval distance, and realize the following steps:
s2.1.1, calculating to obtain free field data, and converting coordinates in the free field data into tuples for storage;
s2.1.2 defining a path through the index tuple;
s2.1.3, setting a field variable to be output;
s2.1.4 repeating steps S2.1.2 and S2.1.3, extracting field variables at different time steps under different paths, and storing the values of the extracted field variables into new tuples;
s2.1.5, after the interval distance is set, inquiring corresponding coordinates in the new tuple to realize extraction.
7. The method for determining the longitudinal seismic value of a subterranean structure according to claim 1, wherein: the construction of the three-dimensional shell-spring model in the step S3.2 specifically comprises the following steps:
S3.2.1, simulating a tunnel duct piece by utilizing a pipe joint shell unit, wherein radial earth springs are arranged on the outer surfaces of the pipe joint shell units, multipoint constraint control points are arranged between adjacent pipe annular shell units, pipe joint springs are arranged between the multipoint constraint control points to simulate joint bolts, and each pipe joint spring comprises a pipe joint axial spring, a pipe joint rotating spring and a pipe joint shearing spring;
s3.2.2, a radial compressive stiffness and two tangential shear stiffness of the earth spring are calculated by the following formulas:
；/> ; wherein K t represents the spring coefficient of foundation soil in tangential unit length, K 1 represents the spring coefficient of foundation soil in radial unit length, G represents the shear modulus of foundation soil corresponding to the maximum strain amplitude of earthquake vibration, and beta represents the conversion coefficient;
S3.2.3 calculating the parameters of the internode springs through a model.
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