CN112632837A - Method for determining longitudinal seismic resistance value of underground structure - Google Patents
Method for determining longitudinal seismic resistance value of underground structure Download PDFInfo
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Abstract
The invention provides a method for determining a longitudinal anti-seismic numerical value of an underground structure, which adopts a sandy soil liquefaction structure to assign values to soil layer material parameters, completes the conversion of the sandy soil liquefaction structure from theory to practical application, realizes the combination of three-dimensional free field nonlinear seismic effect analysis and underground structure longitudinal shell-spring model anti-seismic analysis, and realizes the assignment of soil spring displacement time course through the extraction of underground structure cross section displacement time course passing through a three-dimensional free field, thereby obtaining the longitudinal anti-seismic numerical value of the underground structure.
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 economy and improvement of comprehensive national strength in China, the development speed of underground engineering in large and medium-sized cities is accelerated, and the development of tunnel construction scale in China is more rapid. Many of the 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 strong earthquake motion is especially important.
In order to solve the longitudinal seismic reaction of the large shield tunnel under the action of strong earthquake, scholars at home and abroad construct various models for research.
The 'analysis of longitudinal seismic response of a river-crossing shield tunnel based on a generalized response displacement method' of Miao-Yu et al researches the opening amount between pipe rings by establishing a two-dimensional free field numerical model, extracting the displacement time course response of the middle point of the corresponding pipe ring at the position of the tunnel, inputting a series of displacement time course responses into the fixed end of a foundation spring, and analyzing the longitudinal seismic response of the submarine long and large shield tunnel through the calculation of a longitudinal beam-spring model. Due to the limitation of a two-dimensional free field numerical model, three-dimensional parameters of a soil body spring cannot be completely extracted, multi-directional displacement response around a tunnel cannot be extracted in a self-defined mode, and geometric nonuniformity of a soil body three-dimensional space cannot be considered. Moreover, the constitutive model adopted in the above thesis is only a total stress method constitutive model, and the influence of soil liquefaction cannot be considered, meanwhile, the beam-spring model cannot observe the stress condition of the local details of the structure, the coefficients of the pipe ring connecting springs and the soil springs are difficult, the longitudinal length of the shield tunnel is long, the penetration of the tunnel is complex, the longitudinal pipe rings are connected through a large number of bolts, and the discontinuity of the tunnel structure rigidity is large, so that the existing long and large underground structure earthquake-resistant calculation theory cannot fully reflect the integral rigidity and deformation characteristics of the pipe rings.
For the above reasons, the longitudinal seismic direction is still valuable for further research.
Disclosure of Invention
In order to solve the defects of the prior art, the invention provides a method for determining a longitudinal earthquake-resistant numerical value of an underground structure, which is characterized in that a sandy soil liquefaction structure is adopted to assign values to soil layer material parameters, the conversion from theory to practical application of the sandy soil liquefaction structure is completed, the combination of three-dimensional free field nonlinear earthquake effect analysis and underground structure longitudinal shell-spring model earthquake-resistant analysis is realized, so that the longitudinal earthquake-resistant numerical value of the underground structure is obtained, the stress condition of the underground structure can be truly reflected, not only the annular section of a shield tunnel type can be calculated, but also the square section of an immersed tube and a pipe gallery type can be calculated, and meanwhile, the assignment is carried out by establishing a soil body model, so that the stress condition of the underground structure can be truly reflected, and the applicable.
The technical scheme adopted by the invention for solving the technical problem is as follows: the method for determining the longitudinal seismic resistance value of the underground structure comprises the following steps:
s1, analyzing the 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 the soil layer and/or rock stratum decomposition coordinate data;
s1.3, assigning values to soil layer material parameters in a refined true three-dimensional free field model by adopting a sandy soil liquefaction structure;
s1.4, calculating viscoelasticity artificial boundary parameters, selecting bedrock earthquake motion, taking a viscoelasticity boundary as a boundary condition, and applying earthquake motion consistency input or non-consistency input at bedrock in a refined true three-dimensional free field model;
s1.5, refining the true three-dimensional free field model for calculation to obtain an earthquake response analysis result;
s2, extracting a displacement time course passing through the position of the large and large underground structure in the refined true three-dimensional free field model at any selected interval:
s2.1, setting a spacing distance, and extracting each coordinate of the cross section of the underground structure at 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, underground structure longitudinal shell-spring model earthquake resistance analysis:
s3.1, extracting the 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 the three-dimensional free field calculation 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 seismic reaction analysis result of the long and large underground structure.
Extracting soil layer and/or rock stratum decomposition coordinate data according to a geological survey result in the step S1.1, extracting a displacement time course passing through any selected interval of positions of a long and large underground structure in a 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 a displacement time course in the step S3.4, and respectively realizing the extraction through Python compiling.
The refined true three-dimensional free field model in the step S1.2 is established through the following processes:
s1.2.1, defining nodes on the axis of the tunnel model;
s1.2.2, defining the units needed by the tunnel model;
s1.2.3, defining material properties and interface properties;
s1.2.2, defining the constraint relation between the node of the simulated joint part and the end point of the pipe joint;
s1.2.2, assembling the above parts into a tunnel model for calculation and analysis.
S1.3, the assignment of soil layer material parameters in the refined true three-dimensional free field model by adopting the sandy soil liquefaction constitutive structure specifically comprises the following processes:
s1.3.1, adopting a nested yield surface hardening rule as a theoretical frame to improve the yield surface hardening rule in the elastic-plastic constitutive model of the original stress-strain mixed space;
s1.3.2, replacing an original shear strain algorithm in the elastic-plastic constitutive model of the original stress-strain mixed space by adopting an optimized equivalent shear strain algorithm;
s1.3.3, developing a three-dimensional explicit submodule of an elastic-plastic constitutive model of a stress-strain mixed space improved by S1.3.1 and 1.3.2 based on an ABAQUS explicit module (VUMAT), obtaining a sandy soil liquefaction constitutive model, and carrying out soil layer material parameter assignment;
the position of the grown underground structure in the step S2 includes the periphery of the cross section and the longitudinal range of the grown underground structure.
S2.1, setting the spacing distance, extracting each coordinate of the underground structure cross section of the spacing distance, and realizing the following processes:
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 by 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 under different time steps under different paths, and storing the values of the extracted field variables into a new tuple;
s2.1.5, after the spacing distance is set, the corresponding coordinates are inquired in the new tuple to realize extraction.
The step S3.2 of constructing the three-dimensional shell-spring model specifically comprises the following processes:
s3.2.1, simulating a tunnel segment by using a pipe joint shell unit, wherein the outer surface of the pipe joint shell unit is provided with a radial soil spring, a multi-point constraint control point is arranged between adjacent pipe ring shell units, an inter-pipe joint spring is arranged between the multi-point constraint control points to simulate a joint bolt, and the inter-pipe joint spring comprises an inter-pipe joint axial spring, an inter-pipe joint rotating spring and an inter-pipe joint shearing spring;
s3.2.2, a radial compressive stiffness and two tangential shear stiffnesses of the earth spring are calculated by the following equations:
Kt＝3G
K1＝βKt
in the formula KtExpressing the spring constant of the foundation soil in tangential unit length, K1The spring coefficient of the foundation soil in the radial unit length, G represents the shear modulus of the foundation soil corresponding to the maximum strain amplitude of earthquake vibration, measured through soil test data, and beta represents a conversion coefficient;
s3.2.3, calculating the parameters of the spring between the pipe joints through a model.
The invention has the beneficial effects based on the technical scheme that:
(1) the method for determining the longitudinal earthquake-resistant numerical value of the underground structure combines the nonlinear earthquake effect analysis of the three-dimensional free field with the longitudinal shell-spring model earthquake-resistant analysis of the underground structure, and realizes the assignment of the displacement time course of the earth spring by extracting the displacement time course of the cross section of the underground structure passing through the three-dimensional free field, thereby obtaining the longitudinal earthquake-resistant numerical value of the underground structure;
(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 provided by the invention can consider the space geometric effect, and the calculation result is more consistent with the actual numerical value;
(3) the method for determining the longitudinal earthquake resistance value of the underground structure adopts a sandy soil liquefaction structure to assign values to soil layer material parameters, although scholars such as Yang and Ahmed provide theoretical basis for the model, the following technical difficulties still exist in practical application: the problem of overlarge state variable memory capacity occurs when large three-dimensional finite element numerical calculation is carried out, the calculation efficiency and precision are lower when numerical analysis is carried out, and no explicit secondary development is carried out by any person; the method adopts a 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 caused by overlarge state variable memory when large-scale three-dimensional numerical calculation is carried out, adopts a new optimized equivalent shear strain algorithm so as to solve the problems of numerical calculation efficiency and result precision, and simultaneously utilizes an ABAQUS display module to develop a three-dimensional display subprogram module of the constitutive model so as to be suitable for analyzing the nonlinear problem of three-dimensional (including two-dimensional) soil body;
(4) according to the method for determining the longitudinal anti-seismic numerical value of the underground structure, provided by the invention, a refined true three-dimensional free field model is utilized to simulate the tunnel structure, a combination form of multi-point constraint control points and springs is adopted, the forms of pipe joint shell units are rich, not only can the annular section of a shield tunnel type be calculated, but also the square section of an immersed pipe and a pipe gallery type can be calculated, meanwhile, assignment is carried out by establishing a soil body model, the stress condition of the underground structure can be truly reflected, and the method is wide in application scene.
Drawings
FIG. 1 is a schematic flow chart of a method for determining longitudinal seismic resistance values of an underground structure provided by the invention.
Fig. 2 is a schematic view of a pipe joint-shell unit model, wherein fig. 2(a) is a schematic view of multi-point constraint connection of a tunnel pipe ring, fig. 2(b) is a schematic view of multi-point constraint connection of a pipe gallery pipe ring, and fig. 2(c) is a schematic view of connection of adjacent multi-point constraint control points.
Fig. 3 is a schematic drawing of the tension-compression deformation of the tunnel segment.
FIG. 4 is a view of the tension and compression anisotropic nonlinear spring structure between the tube rings.
FIG. 5 is a view of an inter-tube-ring rotational non-linear spring mechanism.
FIG. 6 is a graph of the stress-strain of the tie bolt in the elastic state.
In the figure, 1-finite element mesh, 2-multipoint constraint control points, 3-constraint reference points and 4-tube internode springs.
Detailed Description
The invention is further illustrated by the following figures and examples.
Referring to fig. 1, a method for determining a longitudinal seismic resistance value of an underground structure is provided, which comprises the following steps:
s1, analyzing the 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 the soil layer and/or rock stratum decomposition coordinate data; the refined true three-dimensional free field model is established through the following processes:
s1.2.1, defining a node on the axis of the immersed tube tunnel model;
s1.2.2, defining units required by the immersed tunnel model;
s1.2.3, defining material properties and interface properties;
s1.2.2, defining the constraint relation between the node of the simulated joint part and the end point of the pipe joint;
s1.2.2, assembling the components into a immersed tube tunnel model for calculation and analysis;
s1.3, assigning values to soil layer material parameters in a refined true three-dimensional free field model by adopting a sandy soil liquefaction structure;
in this embodiment, the sandy soil liquefaction constitutive model is improved on the basis of the traditional elastic-plastic constitutive model of the stress-strain mixed space. Because the students such as Yang and Ahmed only provide theoretical basis, the practical application still has the technical difficulties that the memory quantity of the state variable is overlarge when the numerical value of the large three-dimensional finite element is calculated, the calculation efficiency and the precision are lower when the numerical value is analyzed, and no people perform explicit secondary development, etc., therefore, the sandy soil liquefaction structure is developed through the following processes and then is embedded into ABAQUS finite element software:
s1.3.1, adopting a nested yield surface hardening rule as a theoretical frame to improve the yield surface hardening rule in the elastic-plastic constitutive model of the original stress-strain mixed space;
s1.3.2, replacing an original shear strain algorithm in the elastic-plastic constitutive model of the original stress-strain mixed space by adopting an optimized equivalent shear strain algorithm;
s1.3.3, developing a three-dimensional explicit submodule of an elastic-plastic constitutive model of a stress-strain mixed space improved by S1.3.1 and 1.3.2 based on an ABAQUS display module to obtain a sandy soil liquefaction constitutive model, and carrying out coating material parameter assignment;
through the steps, the influence of soil layer liquefaction can be calculated, so that the calculation result is closer to a true value;
s1.4, calculating viscoelasticity artificial boundary parameters, selecting bedrock seismic oscillation, taking viscoelasticity convenience as a boundary condition, and applying seismic oscillation consistency input or non-consistency input to bedrock in a refined true three-dimensional free field model;
the data source of the bedrock seismic oscillation is a Japanese kik-net database;
s1.5, refining the true three-dimensional free field model for calculation to obtain an earthquake effect analysis result;
s2, extracting a displacement time course passing through the position (including the periphery of the cross section and the longitudinal range of the growing underground structure) of the growing underground structure in the refined true three-dimensional free field model at any selected interval:
s2.1, setting a fixed distance, and extracting each coordinate of the cross section of the underground structure at intervals of the fixed distance;
in the existing processing mode, observation points need to be preset when a model planning grid is just built, and fixed interval distance displacement needs to be set, so that the technical requirement on grid division is very high, and even modeling aiming at a three-dimensional uneven field cannot be realized at all; the modeling is completed in the mode, the spacing distance of subsequently 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 the 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 an excel file of coordinate values 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 through a for loop, extracting field variables under different time steps under different paths, storing the values of the extracted field variables into a new tuple, and writing the result into an excel document;
s2.1.5, after setting the spacing distance, inquiring the corresponding coordinates in the new tuple to realize extraction;
through the processing of the steps, the problem of grid division does not need to be considered when data are extracted, the time for dividing the grid is greatly saved, and a free field model does not need to be built and calculated when other long and large underground structure problems are analyzed subsequently, so that the calculation resource and time are 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 such a three-dimensional inhomogeneous free field model requiring the presetting of an observation point by using the existing method takes more than 20 hours, and the modeling only needs about 10 hours after the presetting point is removed; the data extraction time is greatly reduced, the original tunnel data extraction time of 6km is 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, underground structure longitudinal shell-spring model earthquake resistance analysis:
s3.1, extracting the 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 processes:
s3.2.1, referring to fig. 2, a tunnel segment is simulated by using tube segment shell units, the tube segment shell units can be realized by finite element grids 1, each finite element grid is provided with a constraint reference point 3 to facilitate display and operation in the system, the outer surface of each tube segment shell unit is provided with a radial soil spring, a multi-point constraint control point 2 is arranged between adjacent tube ring shell units, an inter-tube segment spring 4 is arranged between the multi-point constraint control points to simulate a joint bolt, and the inter-tube segment spring comprises an inter-tube segment joint axial spring, an inter-tube segment joint rotating spring and an inter-tube 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 fig. 2(a) and used for calculating circular section structures such as a shield tunnel and the like; the square structure can also be set as the square structure shown in the figure 2(b) and is used for calculating the square section structures such as immersed tubes, tube corridors and the like;
s3.2.2, a radial compressive stiffness and two tangential shear stiffnesses of the earth spring are calculated by the following equations:
Kt＝3G (1)
K1＝βKt (2)
in the formula KtExpressing the spring constant of the foundation soil in tangential unit length, K1The spring coefficient of the foundation soil in the radial unit length, G represents the shear modulus of the foundation soil corresponding to the maximum strain amplitude of earthquake vibration, measured through soil test data, and beta represents a conversion coefficient;
s3.2.3, calculating the parameters of the spring between the pipe joints through a model:
s3.2.3.1, coupling axial spring between pipe joints:
referring to fig. 3, when the tunnel shield segment is pulled, the axial tensile stiffness of the joint is considered to be the sum of the stiffness of each connecting bolt; when the pipe ring is pressed, only the pipe section is pressed at the moment, the connecting bolt is not stressed any more, and the axial compression rigidity of the joint can be regarded as the compression rigidity of the pipe section. The longitudinal joint can be modeled as a nonlinear spring with different tensile and compressive properties as shown in fig. 4, depending on the elasto-plastic stress characteristics of the bolts at the joint.
According to the model, the axial spring stiffness K of the joint between the pipe jointsuThe method can be respectively calculated according to the following sections of the atmosphere in the stress stage, wherein the compressive rigidity is as follows:
in the formula, EcIs the modulus of elasticity of concrete, AcIs the cross-sectional area of the pipe ring, /)sIs the length of the pipe ring;
the tensile elastic stiffness is:
Ku1＝nks1 (4)
the post-yield stiffness was:
Ku2＝nks2 (6)
wherein n is the number of bolts, ks1For elastic stiffness of individual bolts, ks2For post-yield stiffness of a single bolt, l is the bolt length, AsIs the cross-sectional area of the bolt, EsIs the elastic modulus of the bolt, and alpha is the elastic stiffness ratio;
the joint elastic limit tension is as follows:
Ny＝nAs(fy-P) (8)
the corresponding elastic modulus limit deformations are:
the ultimate tensile force of the joint is as follows:
Nm＝nAs(fm-P) (10)
the corresponding limit deformations are:
in the formula (f)yIs the bolt yield stress, fmIs the ultimate stress of the bolt, and P is the prestress of the bolt;
s3.2.3.2, joint rotating spring between pipe joints:
referring to fig. 5, when the inter-ring joint is bent, the tensile stress is borne by the connecting bolt in the tension area, the compressive stress is borne by the pipe section concrete alone in the compression area, and the pipe section concrete stress is always in an elastic state; deformation of cross sectionConforming to the assumption of a flat section and small deformations. When the joint bolt is fully elastic, the stresses and deformations are as shown in FIG. 6, x,
Respectively, the position and angle of the neutral axis, wherein
The deformation of the tension zone only contains the deformation of the joint bolt and does not contain the tension deformation of concrete, which is different from an equivalent continuous beam model because the joint and the pipe ring are respectively considered in the calculation process of the model, so the deformation of the bolt between the rings only needs to be reflected in the tension zone when the rotational stiffness of the joint is calculated.
The deformation coordination conditions of the joint are as follows:
in the formula, epsiloncThe concrete compressive strain at the edge of the pipe ring is shown, theta is the joint corner, D is the outside diameter of the pipe ring, r is the average value of the inside and outside radii of the pipe ring, and deltajThe maximum opening amount of the pipe ring joint is obtained;
the joint force balance conditions were:
wherein t is the pipe ring thickness, krLinear stiffness, k, of tension spring for inter-loop jointr＝Ku1L (2 π r) or ku2/(2πr)；
The formula (15) can be substituted with the formulae (12) to (14):
wherein
According to the deformation coordination condition and the force balance condition, the bending rigidity expression of the joint is as follows:
the yield bending moment is as follows:
the ultimate bending moment is as follows:
wherein, Kθ1Represents a first deformation range section 1-thetayFlexural rigidity of the inner joint, Kθ2Represents a first deformation range section thetay～θmThe inner joint bending stiffness.
S3.2.3.3, the inter-joint shear spring can be assumed to be infinite;
s3.3, assigning the displacement time course obtained by the three-dimensional free field calculation 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 seismic reaction analysis result of the long and large underground structure.
Extracting soil layer and/or rock stratum decomposition coordinate data according to a geological survey result in the step S1.1, extracting a displacement time course passing through any selected interval of positions of a long and large underground structure in a 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 a displacement time course in the step S3.4, and respectively realizing the extraction through Python compiling.
In order to verify the advancement of the invention, the traditional beam-spring model is taken as a control group to carry out simulation experiment comparison:
generally, a 3D refinement time-course analysis method is considered to be a relatively accurate analysis method, but because the algorithm complexity is high, the time consumption is large, and the practical application is limited, the method is generally used as an evaluation standard. The method comprises the following steps of selecting seismic waves under five working conditions, respectively substituting the seismic waves into a 3D refined model, a beam-spring model and a complete model provided by the invention to calculate the opening amount of an inter-annular joint, taking the opening amount of the inter-annular joint as equivalent data of a longitudinal anti-seismic numerical value of the underground structure, and respectively calculating errors of the beam-spring model and the complete model provided by the invention by taking a result obtained by calculating the 3D refined model as a reference, thus obtaining the following data:
TABLE 1 comparison of the opening peak values of the joints between rings under different analytical models
The comparison shows that the error of the opening amount of the inter-ring joint calculated by the underground structure longitudinal seismic numerical value determining method provided by the invention is obviously smaller than the calculation result of the traditional beam-spring model, is very close to a 3D fine model, and even has an error amount of only 8.08 percent with the 3D fine model under the condition of selecting certain seismic waves. Due to the operability of the method, compared with a 3D refined model, the method has better practicability, and can be used for researching the longitudinal seismic reaction of the underground tunnel through sectional calculation.
The invention provides a method for determining a longitudinal anti-seismic numerical value of an underground structure, which adopts a sandy soil liquefaction structure to assign values to soil layer material parameters, completes the conversion of the sandy soil liquefaction structure from theory to practical application, realizes the combination of three-dimensional free field nonlinear seismic effect analysis and underground structure longitudinal shell-spring model anti-seismic analysis, and realizes the assignment of soil spring displacement time course through the extraction of underground structure cross section displacement time course passing through a three-dimensional free field, thereby obtaining the longitudinal anti-seismic numerical value of the underground structure.
Claims (7)
1. A method for determining a longitudinal earthquake resistance value of an underground structure is characterized by comprising the following steps:
s1, analyzing the 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 the soil layer and/or rock stratum decomposition coordinate data;
s1.3, assigning values to soil layer material parameters in a refined true three-dimensional free field model by adopting a sandy soil liquefaction structure;
s1.4, calculating viscoelasticity artificial boundary parameters, selecting bedrock earthquake motion, taking a viscoelasticity boundary as a boundary condition, and applying earthquake motion consistency input or non-consistency input at bedrock in a refined true three-dimensional free field model;
s1.5, refining the true three-dimensional free field model for calculation to obtain an earthquake response analysis result;
s2, extracting a displacement time course passing through the position of the large and large underground structure in the refined true three-dimensional free field model at any selected interval:
s2.1, setting a spacing distance, and extracting each coordinate of the cross section of the underground structure at 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, underground structure longitudinal shell-spring model earthquake resistance analysis:
s3.1, extracting the 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 the three-dimensional free field calculation 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 seismic reaction analysis result of the long and large underground structure.
2. A method for determining a longitudinal seismic resistance value of a subterranean structure according to claim 1, wherein: extracting soil layer and/or rock stratum decomposition coordinate data according to a geological survey result in the step S1.1, extracting a displacement time course passing through any selected interval of positions of a long and large underground structure in a 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 a displacement time course in the step S3.4, and respectively realizing the extraction through Python compiling.
3. A method for determining a longitudinal seismic resistance value of a subterranean structure according to claim 1, wherein: the refined true three-dimensional free field model in the step S1.2 is established through the following processes:
s1.2.1, defining nodes on the axis of the tunnel model;
s1.2.2, defining the units needed by the tunnel model;
s1.2.3, defining material properties and interface properties;
s1.2.2, defining the constraint relation between the node of the simulated joint part and the end point of the pipe joint;
s1.2.2, assembling the above parts into a tunnel model for calculation and analysis.
4. A method for determining a longitudinal seismic resistance value of a subterranean structure according to claim 1, wherein: s1.3, the assignment of soil layer material parameters in the refined true three-dimensional free field model by adopting the sandy soil liquefaction constitutive structure specifically comprises the following processes:
s1.3.1, adopting a nested yield surface hardening rule as a theoretical frame to improve the yield surface hardening rule in the elastic-plastic constitutive model of the original stress-strain mixed space;
s1.3.2, replacing an original shear strain algorithm in the elastic-plastic constitutive model of the original stress-strain mixed space by adopting an optimized equivalent shear strain algorithm;
s1.3.3, developing a three-dimensional explicit submodule of the elastic-plastic constitutive model of the stress-strain mixed space improved by S1.3.1 and 1.3.2 based on an ABAQUS explicit module to obtain a sandy soil liquefaction constitutive model, and carrying out soil layer material parameter assignment.
5. A method for determining a longitudinal seismic resistance value of a subterranean structure according to claim 1, wherein: the position of the grown underground structure in the step S2 includes the periphery of the cross section and the longitudinal range of the grown underground structure.
6. A method for determining a longitudinal seismic resistance value of a subterranean structure according to claim 1, wherein: s2.1, setting the spacing distance, extracting each coordinate of the underground structure cross section of the spacing distance, and realizing the following processes:
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 by 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 under different time steps under different paths, and storing the values of the extracted field variables into a new tuple;
s2.1.5, after the spacing distance is set, the corresponding coordinates are inquired in the new tuple to realize extraction.
7. A method for determining a longitudinal seismic resistance value of a subterranean structure according to claim 1, wherein: the step S3.2 of constructing the three-dimensional shell-spring model specifically comprises the following processes:
s3.2.1, simulating a tunnel segment by using a pipe joint shell unit, wherein the outer surface of the pipe joint shell unit is provided with a radial soil spring, a multi-point constraint control point is arranged between adjacent pipe ring shell units, an inter-pipe joint spring is arranged between the multi-point constraint control points to simulate a joint bolt, and the inter-pipe joint spring comprises an inter-pipe joint axial spring, an inter-pipe joint rotating spring and an inter-pipe joint shearing spring;
s3.2.2, a radial compressive stiffness and two tangential shear stiffnesses of the earth spring are calculated by the following equations:
Kt＝3G
K1＝βKt
in the formula KtExpressing the spring constant of the foundation soil in tangential unit length, K1The spring coefficient of the foundation soil in the radial unit length, G represents the shear modulus of the foundation soil corresponding to the maximum strain amplitude of earthquake vibration, measured through soil test data, and beta represents a conversion coefficient;
s3.2.3, calculating the parameters of the spring between the pipe joints through a model.
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| CN114704288A (en) * | 2022-05-18 | 2022-07-05 | 华中科技大学 | A shock attenuation is from restoring to throne tunnel structure for broken area of fault |
| CN116306099A (en) * | 2023-02-06 | 2023-06-23 | 武汉大学 | Random field-based evaluation method for lateral movement of liquefiable site reinforced by gravel piles |
| CN117216862A (en) * | 2023-11-09 | 2023-12-12 | 湖南大学 | Three-dimensional shield tunnel dynamic analysis model based on fiber beam unit |
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| CN114704288A (en) * | 2022-05-18 | 2022-07-05 | 华中科技大学 | A shock attenuation is from restoring to throne tunnel structure for broken area of fault |
| CN114704288B (en) * | 2022-05-18 | 2022-11-29 | 华中科技大学 | A shock attenuation is from restoring to throne tunnel structure for broken area of fault |
| CN116306099A (en) * | 2023-02-06 | 2023-06-23 | 武汉大学 | Random field-based evaluation method for lateral movement of liquefiable site reinforced by gravel piles |
| CN117216862A (en) * | 2023-11-09 | 2023-12-12 | 湖南大学 | Three-dimensional shield tunnel dynamic analysis model based on fiber beam unit |
| CN117216862B (en) * | 2023-11-09 | 2024-02-02 | 湖南大学 | Three-dimensional shield tunnel dynamic analysis model based on fiber beam unit |
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