A method and system for constructing a dynamic calculation model of a limited position shock insulation cushion layer

Abstract

The application belongs to the technical field of building shock absorption and isolation, and discloses a method and system for constructing a dynamic calculation model of a limiting shock isolation cushion layer, which comprises the following steps: firstly, cyclic shear tests under different stress states are carried out to obtain a hysteresis curve; secondly, the hysteresis curve is divided into three stages, namely, overall shear deformation, interlayer slip and limiter constraint; then, theoretical models of the three stages are constructed by using viscoelastic model, Coulomb friction model and bilinear model respectively; then, the optimal solution of the model parameters is determined by fitting the test data through the least square method; then, a regression relationship between the parameters and the stress state is established to form a dynamic calculation model based on the stress state; finally, the prediction ability of the model is verified by using test conditions not participating in the regression, so that the dynamic shear stress-shear strain relationship in different shear deformation stages can be accurately predicted.

Description

Technical Field

[0001] This invention belongs to the field of building seismic isolation technology, specifically relating to a method and system for constructing a dynamic calculation model of a limited seismic isolation cushion layer. Background Technology

[0002] Earthquakes, due to their high intensity, wide impact range, low predictability, and high frequency, have become one of the most serious natural disasters. In rural and urban areas, housing structures are primarily masonry structures, which have poor seismic resistance. The lack of seismic fortification measures makes these buildings prone to large-scale collapses under earthquakes, leading to serious consequences such as casualties and economic losses. Therefore, finding seismic isolation measures suitable for low- and medium-rise masonry buildings in rural and urban areas is of practical significance. In recent years, the method of using geosynthetic materials to reinforce backfill soil to form a seismic isolation layer has been successfully applied to the seismic isolation of low- and medium-rise buildings, proving to be an economical and effective building seismic isolation measure.

[0003] Generally, the development law of soil deformation strength under dynamic load and the basic indicators characterizing the dynamic properties of soil need to be obtained through indoor or field dynamic tests. Common test methods mainly include dynamic triaxial tests, resonant column tests, and dynamic shear tests. Based on the obtained dynamic characteristic parameters, a dynamic constitutive model is constructed to describe the corresponding soil, realizing numerical simulation of the dynamic response of the structure under different seismic conditions. Currently, the more common dynamic constitutive models used to describe the stress-strain relationship of soil mainly include viscoelastic models, elastoplastic models, and bilinear models. Considering that geotextile cushions are three-dimensional encapsulated bodies, their shear deformation mode changes compared to pure soil under seismic loads. Directly applying existing soil dynamic constitutive models to such seismic isolation cushions cannot fully consider the constraint effect of the encapsulating material on the soil and the discontinuous deformation characteristics of the seismic isolation cushions. Therefore, it is urgent to establish a dynamic calculation model that can describe the entire process of shear deformation of seismic isolation cushions under seismic conditions, providing a theoretical basis for the application of new seismic isolation technologies such as geotextile cushions. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides a method and system for constructing a dynamic calculation model for a confined seismic isolation layer. The method obtains the shear stress-shear strain relationship of the isolation layer through shear tests, constructs a theoretical model based on the experimental data that reflects the discontinuous deformation law of the confined seismic isolation layer, and determines the model parameters through regression analysis. This method can optimize the dynamic calculation model of the confined seismic isolation layer based on experimental results and predict the shear stress-shear strain relationship at different shear deformation stages.

[0005] To achieve the above objectives, the present invention provides the following solution: A method for constructing a dynamic calculation model for a seismic isolation layer, the method comprising: S1: Conduct cyclic shear tests on the confined isolation pad under different stress states, and obtain the shear stress-shear strain relationship under different working conditions, i.e., the hysteresis curve of the confined isolation pad. S2: The hysteresis curve morphology of the confined isolation pad under different stress states is analyzed and divided into three stages: overall shear deformation, interlayer slip and confined device constraint. S3: Based on the hysteresis curve morphology characteristics of the confined isolation pad at different shear deformation stages, viscoelastic model, Coulomb friction model and bilinear model are used to construct theoretical models of shear stress-shear strain relationship of the confined isolation pad at different shear deformation stages. S4: Combine the obtained shear stress-shear strain relationship with the theoretical model of the shear stress-shear strain relationship of the confined isolation cushion layer at different shear deformation stages, and use the least squares method to fit the experimental data to obtain the optimal solution of the parameters of the constructed theoretical model. S5: Perform regression analysis on the relationship between the optimal solution of the theoretical model parameters and the stress state parameters to establish a dynamic calculation model of the confined isolation cushion layer based on stress state and considering discontinuous deformation; S6: Substitute the stress state parameters corresponding to the test conditions that were not used in the model regression analysis into the constructed dynamic calculation model of the confined isolation cushion layer to predict the shear stress-shear strain relationship at different shear deformation stages.

[0006] Preferably, in step S1, the method for conducting cyclic shear tests on the confined isolation cushion under different stress states and obtaining the shear stress-shear strain relationship under different working conditions, i.e., the hysteresis curve of the confined isolation cushion, includes: ; ; ; In the formula: The calculated dynamic shear stress of the specimen; This refers to the real-time shear force of the loaded plate. The real-time compression ratio of the sample; This represents the initial contact area of ​​the sample. The height at the initial contact moment of the sample; This refers to the real-time height of the sample. γ The calculated dynamic shear strain of the specimen; x This represents the displacement of the upper surface of the sample relative to the lower surface.

[0007] Preferably, in S2, the first stage is the overall shear deformation stage, in which the entire isolation pad undergoes shear deformation; the second stage is the interlayer slip stage, in which any adjacent pads undergo relative slip; and the third stage is the limiter constraint stage, in which the isolation pad comes into contact with the limiter, and the limiter exerts a lateral constraint force on it.

[0008] Preferably, in step S3, the method for determining the theoretical model of the shear stress-shear strain relationship of the confined isolation pad at different shear deformation stages is constructed using a viscoelastic model, a Coulomb friction model, and a bilinear model, respectively, based on the hysteresis curve morphology characteristics of the confined isolation pad at different shear deformation stages. The overall shear deformation stage is described by a viscoelastic model, which represents the nonlinear shear deformation of the cushion layer. Its shear stress-strain hysteresis curve is expressed as follows: ; In the formula: This refers to the first stage of dynamic shear stress. To unload the instantaneous dynamic shear strain; To unload the instantaneous dynamic shear stress; This is the initial shear modulus; This represents the maximum dynamic shear stress. The influence coefficient of the bag material; The shear stress-shear strain hysteresis curves during the interlayer slip stage are described using the Coulomb friction model: ; In the formula: This refers to the second stage of dynamic shear stress. This represents the displacement of the upper surface of the sample relative to the lower surface. This refers to the normal stress on the seismic isolation pad. The friction angle of the inclusion body; It is a cohesive force of the inclusion body; The constraint phase of the limit switch is described using a bilinear model: ; ; ; In the formula: This refers to the third stage of dynamic shear stress. The lateral constraint force generated by the limit switch; This refers to the bottom area of ​​the seismic isolation pad. This is the initial stiffness of the limiter; This is the ratio of the stiffness of the limiter after yielding to its initial stiffness; Allowance for free deformation in the design; This is the yield displacement of the limit switch. These are variables that describe the hysteresis characteristics of the limit switch.

[0009] Preferably, in step S5, the method for establishing a dynamic calculation model of the confined isolation cushion layer based on stress state and considering discontinuous deformation by performing regression analysis on the optimal solution of the constructed theoretical model parameters and stress state parameters includes: ; ; In the formula: This is the initial shear modulus correction value for the first stage, i.e., the overall shear deformation stage; This is the characterization function for the initial shear modulus correction value in the first stage; This represents the accumulated shear strain in the first stage. This is the shear stress correction value for the second stage, namely the interlayer slip stage; This is the characterization function for the second-stage shear stress correction value; This represents the cumulative shear strain in the second stage.

[0010] The present invention also provides a dynamic calculation model construction system for a seismic isolation cushion layer, the system being used to implement the aforementioned method, the system comprising: a cyclic shear test module, a stage feature analysis module, a segmented model construction module, a parameter optimization and identification module, a stress correlation modeling module, and a model verification and prediction module; The cyclic shear test module is used to conduct cyclic shear tests on the confined isolation cushion under different stress states, and after conversion, the shear stress-shear strain relationship under different working conditions is obtained, that is, the hysteresis curve of the confined isolation cushion. The stage feature analysis module is used to analyze the hysteresis curve morphology of the confined isolation pad under different stress states, and divides it into three stages: overall shear deformation, interlayer slip, and confined device constraint. The segmented model construction module is used to construct the hysteresis curve morphology characteristics of the confined isolation pad at different shear deformation stages using viscoelastic model, Coulomb friction model and bilinear model respectively, to determine the theoretical model of shear stress-shear strain relationship of the confined isolation pad at different shear deformation stages. The parameter optimization and identification module is used to combine the obtained shear stress-shear strain relationship with the theoretical model of the shear stress-shear strain relationship of the confined isolation cushion layer at different shear deformation stages, and use the least squares method to fit the experimental data to obtain the optimal solution of the parameters of the constructed theoretical model. The stress correlation modeling module is used to perform regression analysis on the relationship between the optimal solution of the constructed theoretical model parameters and the stress state parameters, and to establish a dynamic calculation model of the confined isolation cushion layer based on stress state and considering discontinuous deformation. The model verification and prediction module is used to substitute the stress state parameters corresponding to the test conditions that were not used in the model regression analysis into the constructed dynamic calculation model of the confined isolation cushion layer, so as to predict the shear stress-shear strain relationship at different shear deformation stages.

[0011] Preferably, in the cyclic shear test module, the process of conducting cyclic shear tests on the confined isolation pad under different stress states and obtaining the shear stress-shear strain relationship under different working conditions, i.e., the hysteresis curve of the confined isolation pad, includes: ; ; ; In the formula: The calculated dynamic shear stress of the specimen; This refers to the real-time shear force of the loaded plate. The real-time compression ratio of the sample; This represents the initial contact area of ​​the sample. The height at the initial contact moment of the sample; This refers to the real-time height of the sample. γ The calculated dynamic shear strain of the specimen; x This represents the displacement of the upper surface of the sample relative to the lower surface.

[0012] Preferably, in the stage feature analysis module, the first stage is the overall shear deformation stage, in which the entire isolation pad undergoes shear deformation; the second stage is the interlayer slip stage, in which any adjacent pads undergo relative slip; and the third stage is the limiter constraint stage, in which the isolation pad comes into contact with the limiter, and the limiter exerts a lateral constraint force on it.

[0013] Preferably, in the segmented model construction module, the viscoelastic model, Coulomb friction model, and bilinear model are used to construct the theoretical model of the shear stress-shear strain relationship of the confined isolation pad at different shear deformation stages, based on the hysteresis curve morphology characteristics of the confined isolation pad at different shear deformation stages. The process of determining the theoretical model of the shear stress-shear strain relationship of the confined isolation pad at different shear deformation stages includes: The overall shear deformation stage is described by a viscoelastic model, which represents the nonlinear shear deformation of the cushion layer. Its shear stress-strain hysteresis curve is expressed as follows: ; In the formula: This refers to the first stage of dynamic shear stress. To unload the instantaneous dynamic shear strain; To unload the instantaneous dynamic shear stress; This is the initial shear modulus; This represents the maximum dynamic shear stress. The influence coefficient of the bag material; The shear stress-shear strain hysteresis curves during the interlayer slip stage are described using the Coulomb friction model: ; In the formula: This refers to the second stage of dynamic shear stress. This represents the displacement of the upper surface of the sample relative to the lower surface. The friction angle of the inclusion body; It is a cohesive force of the inclusion body; The constraint phase of the limit switch is described using a bilinear model: ; ; ; In the formula: This refers to the third stage of dynamic shear stress. The lateral constraint force generated by the limit switch; This refers to the bottom area of ​​the seismic isolation pad. This is the initial stiffness of the limiter; This is the ratio of the stiffness of the limiter after yielding to its initial stiffness; This represents the displacement of the upper surface of the vibration isolation pad relative to the lower surface. Allowance for free deformation in the design; This is the yield displacement of the limit switch. These are variables that describe the hysteresis characteristics of the limit switch.

[0014] Preferably, in the stress correlation modeling module, the process of performing regression analysis on the relationship between the optimal solution of the constructed theoretical model parameters and the stress state parameters to establish a dynamic calculation model of the confined isolation cushion layer based on stress state and considering discontinuous deformation includes: ; ; In the formula: This is the initial shear modulus correction value for the first stage, i.e., the overall shear deformation stage; This is the characterization function for the initial shear modulus correction value in the first stage; This represents the accumulated shear strain in the first stage. This is the shear stress correction value for the second stage, namely the interlayer slip stage; This is the characterization function for the second-stage shear stress correction value; This represents the cumulative shear strain in the second stage.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: 1) Based on the indoor cyclic shear test data of the seismic isolation pad under the constraint condition, the applicable parameters can be quickly fitted. The test method is simple and can effectively control the time and cost of dynamic calculation and analysis of the seismic isolation pad under the constraint condition. 2) The dynamic calculation model is constructed based on the shear deformation law of the confined isolation pad, which can take into account the discontinuous deformation characteristics of the confined isolation pad under dynamic conditions and distinguish the shear stress-shear strain hysteresis curve morphology at different deformation stages. 3) This invention constructs a dynamic calculation model for the confined isolation cushion layer based on a theoretical model, with clear mechanical significance. In addition, the least squares method is used to perform regression analysis on the model fitting parameters, considering the influence of shear history on the model parameters to ensure the uniqueness of the model. The constructed dynamic calculation model can be directly used for dynamic simulation analysis of new isolation systems such as geotextile bag isolation cushion layers. Attached Figure Description

[0016] To more clearly illustrate the technical solution of the present invention, the drawings used in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a flowchart illustrating a method for constructing a dynamic calculation model for a seismic isolation layer according to an embodiment of the present invention. Figure 2 The diagram shows the shear stress-shear strain relationship in three stages of the present invention, wherein (a) is the shear stress-shear strain relationship in the first stage of the model constructed in Example 1, (b) is the shear stress-shear strain relationship in the second stage, and (c) is the shear stress-shear strain relationship in the third stage. Figure 3 The following is a schematic diagram of a typical hysteresis curve of the theoretical model in an embodiment of the present invention. (a) is a schematic diagram of a typical hysteresis curve of the isolation pad when it comes into contact with the limiter during the overall shear deformation stage, and (b) is a schematic diagram of a hysteresis curve of the isolation pad when it comes into contact with the limiter during the interlayer slip stage. Figure 4 This is a schematic diagram of the test and prediction results of the single-cycle hysteresis curve of the specimen during the overall shear deformation stage, as recorded in the example. Figure 5 This is a schematic diagram of the single-cycle hysteresis curve test and prediction results of the specimen during the interlayer slip stage, as recorded in the example. Figure 6 This is a schematic diagram of the single-cycle hysteresis curve test and prediction results of the limiter constraint stage specimen recorded in the example. Figure 7 This is a schematic diagram of the test and prediction results of the cyclic shear hysteresis curve of the specimen during the overall shear deformation stage, as recorded in the example. Figure 8 This is a schematic diagram of the test and prediction results of the cyclic shear hysteresis curve of the specimen during the interlayer slip stage, as recorded in the example. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0020] Example 1 This invention provides a method for constructing a dynamic calculation model for a seismic isolation layer, the method comprising: S1. Conduct cyclic shear tests on the confined isolation cushion under different stress states, and obtain the shear stress-shear strain relationship under different working conditions, i.e., the hysteresis curve of the confined isolation cushion. S2. The hysteresis curve morphology of the confined isolation pad under different stress states is analyzed and divided into three stages: overall shear deformation, interlayer slip and confined device constraint. The triggering condition of the confined device deformation needs to be determined. S3. Based on the hysteresis curve morphology characteristics of the confined isolation pad at different shear deformation stages, viscoelastic model, Coulomb friction model and bilinear model are used to construct theoretical models of shear stress-shear strain relationship of the confined isolation pad at different shear deformation stages. S4. Combine the shear stress-shear strain relationship obtained in S1 with the theoretical model determined in S3, and use the least squares method to fit the experimental data to obtain the optimal solution of the parameters of the constructed theoretical model; S5. Regression analysis is performed on the relationship between the parameters of the constructed theoretical model and the parameters of the stress state to establish a dynamic calculation model of the confined isolation cushion layer based on the stress state and considering discontinuous deformation. S6. Substitute the stress state parameters corresponding to the test conditions that were not used for model regression analysis into the constructed dynamic calculation model, obtain the predicted values ​​of the hysteresis curves, and compare them with the hysteresis curves obtained from the experiment to verify the reliability of the dynamic calculation model.

[0021] In this embodiment, the specific steps for obtaining the shear stress-shear strain relationship under different working conditions in S1 are as follows: cyclic single shear tests are conducted on the limiting isolation pad under different normal stress, shear amplitude, and limiter reserved distance amplitude conditions. The tests are completed on a cyclic shear test system such as a cyclic single shear apparatus, and the shear force-displacement curves during the test are recorded. The real-time height of the specimen is corrected according to the recorded vertical displacement, and the shear stress-shear strain relationship of the specimen is obtained after conversion.

[0022] The dynamic shear stress can be corrected and converted based on the real-time contact area and height of the specimen: In the formula: The calculated dynamic shear stress of the specimen; This refers to the real-time shear force of the loaded plate. The real-time compression ratio of the sample; This represents the initial contact area of ​​the sample. The height at the initial contact moment of the sample; The real-time height of the specimen is given. The shear strain of the specimen is corrected based on the real-time specimen height to obtain the shear stress-shear strain relationship of the geotextile bag assembly specimen under different working conditions.

[0023] Dynamic shear strain can be corrected and converted based on the real-time height of the specimen and the amount of deformation: In the formula: γ is the converted dynamic shear strain of the specimen; x This represents the displacement of the upper surface of the sample relative to the lower surface.

[0024] In this embodiment, the hysteresis curve morphology of the limiting isolation pad under different stress states in S2 includes three stages: the first stage is the overall shear deformation stage, in which the isolation pad undergoes overall shear deformation; the second stage is the interlayer slip stage, in which any adjacent pad undergoes relative slip; and the third stage is the limiter constraint stage, in which the isolation pad contacts the limiter, and the limiter generates a lateral constraint force on it.

[0025] In this embodiment, in S3, a calculation model is selected to determine the deformation characteristics of the confined isolation cushion layer at different stages, and a shear stress-shear strain relationship is established to determine the different deformation stages of the confined isolation cushion layer: In the first stage (overall shear deformation stage), a viscoelastic model is used to describe the nonlinear shear deformation of the cushion layer, and its shear stress-shear strain hysteresis curve can be expressed as: In the formula: This refers to the first stage of dynamic shear stress. To unload the instantaneous dynamic shear strain; To unload the instantaneous dynamic shear stress; This is the initial shear modulus; This represents the maximum dynamic shear stress. This represents the influence coefficient of the bag material.

[0026] The shear stress-shear strain hysteresis curves of the second stage (interlayer slip stage) are described using the Coulomb friction model: In the formula: This represents the second stage of dynamic shear stress.

[0027] The third stage (limiter constraint stage) is described using a bilinear model: In the formula: This refers to the third stage of dynamic shear stress. The lateral constraint force generated by the limit switch; This refers to the bottom area of ​​the seismic isolation pad. This is the initial stiffness of the limiter; This is the ratio of the stiffness of the limiter after yielding to its initial stiffness; This represents the displacement of the upper surface of the vibration isolation pad relative to the lower surface. Allowance for free deformation in the design; This is the yield displacement of the limit switch. These are variables that describe the hysteresis characteristics of the limit switch.

[0028] In this embodiment, step S4 requires substituting the experimental dataset of shear stress-shear strain relationship into the proposed theoretical model. ,in Let be the dynamic shear strain at any given time. For the dynamic shear stress at any given time, obtain the fitted value of the model function. The sum of squared residuals (RSS) of the experimental data. When the RSS value is at its minimum, it is possible to obtain the parameters of the constructed model function. param The best fit value.

[0029] In this embodiment, obtaining the parameters of the constructed theoretical model in step S5 requires organizing the model parameter data obtained in step S4 under different working conditions, performing regression analysis, considering the influence of shear history on the model parameters, and correcting the parameters of the dynamic calculation model. The relationship between the corresponding corrected parameters and the cumulative shear strain is as follows: ; In the formula: This is the initial shear modulus correction value for the first stage, i.e., the overall shear deformation stage; This is the characterization function for the initial shear modulus correction value in the first stage; This represents the accumulated shear strain in the first stage. This is the shear stress correction value for the second stage, namely the interlayer slip stage; This is the characterization function for the second-stage shear stress correction value; This represents the cumulative shear strain in the second stage.

[0030] In this embodiment, the test data used in S6 to verify the reliability of the model should be selected from test conditions not used in the model regression analysis stage. If the predicted values ​​of the shear stress-shear strain hysteresis curves obtained are basically consistent with the test results, then the dynamic calculation model can be used to describe the shear deformation law of the confined isolation pad.

[0031] Example 2 This invention provides a method for constructing a dynamic calculation model for a seismic isolation layer, the construction idea of ​​which is as follows: Figure 1 As shown, the specific steps are as follows: S1. Conduct cyclic shear tests on the confined isolation cushion under different stress states, and obtain the shear stress-shear strain relationship under different working conditions, i.e., the hysteresis curve of the confined isolation cushion. The dynamic shear stress can be corrected and converted based on the real-time contact area and height of the specimen. In the formula: The calculated dynamic shear stress of the specimen; This refers to the real-time shear force of the loaded plate. The real-time compression ratio of the sample; This represents the initial contact area of ​​the sample. The height at the initial contact moment of the sample; The real-time height of the specimen is given. The shear strain of the specimen is corrected based on the real-time specimen height to obtain the shear stress-shear strain relationship of the geotextile bag assembly specimen under different working conditions.

[0032] The dynamic shear strain can be corrected and converted based on the real-time height of the specimen and the amount of deformation. In the formula: The calculated dynamic shear strain of the specimen; x This represents the displacement of the upper surface of the sample relative to the lower surface.

[0033] S2. The hysteresis curve morphology of the confined isolation pad under different stress states is analyzed and divided into three stages: overall shear deformation, interlayer slip, and confined device constraint. The criteria for determining whether a process enters the interlayer slip stage or the limiter constraint stage are as follows: 1) When the real-time dynamic shear stress The maximum dynamic shear stress reaches the overall shear deformation stage ,Right now When the limiting isolation pad enters the inter-layer slip stage; 2) when the displacement generated by the limiting isolation pad exceeds the free deformation reserved between the limiter and the pad, that is... The limiting isolation pad layer enters the limiting device constraint stage.

[0034] The hysteresis curve morphology of the sample is related to the location of its deformation: The first stage is the overall shear deformation stage. Because the shear stress on the sample is relatively small, the frictional force generated on the surface of the encapsulation has not yet reached the maximum static friction. Only the tensile deformation of the encapsulation material drives the rotation and sliding of the soil particles inside the bag, thus generating overall shear deformation. The second stage is the interlayer slip stage. As the shear deformation of the sample gradually accumulates, the interlayer frictional force has reached the maximum static friction, and the sample begins to undergo relative interlayer slip, converting the interlayer frictional force into sliding friction. The third stage is the limiter constraint stage. The triggering condition for this stage requires the determination of the sample's deformation. When the relative interlayer slip reaches a certain level, the sample comes into contact with the limiter, and the limiter steel rod undergoes bending deformation after being subjected to horizontal thrust, thus generating a lateral constraint force on the sample. The specific implementation process is as follows: S3.

[0035] S3. Based on the hysteresis curve morphology characteristics of the confined isolation pad at different shear deformation stages, viscoelastic model, Coulomb friction model and bilinear model are used to construct theoretical models of shear stress-shear strain relationship of the confined isolation pad at different shear deformation stages. The first stage (overall shear deformation stage) can be described by an equivalent linear model or an isoviscoelastic model, which describes the nonlinear shear deformation law of the seismic isolation pad. (See...) Figure 2 (a) Its shear stress-shear strain relationship can be expressed as: In the formula: This refers to the first stage of dynamic shear stress. To unload the instantaneous dynamic shear strain; To unload the instantaneous dynamic shear stress; This is the initial shear modulus; The influence coefficient of the bag material; This is a correction factor for the initial shear modulus; This is the influence coefficient of normal stress; This represents the normal stress experienced by the seismic isolation layer.

[0036] The second stage (interlayer slip stage) can be characterized using the Coulomb friction model, see [link to relevant documentation]. Figure 2 (b) Its shear stress-shear strain relationship can be expressed as: In the formula: This refers to the second stage of dynamic shear stress. The friction angle of the inclusion body; It represents the cohesive force of the inclusion body.

[0037] The third stage (limiter constraint stage) can be represented using the Bouc-Wen bilinear model, see [link to relevant documentation]. Figure 2 (c) Its shear stress-shear strain relationship can be expressed as: In the formula: This refers to the third stage dynamic shear stress, which is the additional shear stress generated by the constraint effect of the limiter on the seismic isolation pad. The lateral constraint force generated by the limit switch; The area of ​​the bottom of the package; This is the initial stiffness of the limiter; This is the ratio of the stiffness of the limiter after yielding to its initial stiffness; Allowance for free deformation in the design; The variable describing the hysteresis characteristics of the limit switch has a range of variation. , and when At that time, the limit switch is in the yielding stage; This is the yield displacement of the limit switch.

[0038] S4. Combine the shear stress-shear strain relationship obtained in step 1 with the theoretical model determined in step 3, and use the least squares method to fit the experimental data to obtain the optimal solution of the parameters of the constructed theoretical model; The hysteresis curve morphology of the constructed dynamic calculation model for the confined isolation pad is affected by the triggering conditions of the confined phase. If the isolation pad is in contact with the confined phase in the first stage (overall shear deformation stage), its hysteresis curve morphology is as follows: Figure 3 As shown in (a), the seismic isolation layer comes into contact with the limiter in the second stage (interlayer slip stage), and its hysteresis curve is as follows. Figure 3 As shown in (b).

[0039] S5. Regression analysis is performed on the relationship between the parameters of the constructed theoretical model and the parameters of the stress state to establish a dynamic calculation model of the confined isolation cushion layer based on the stress state and considering discontinuous deformation. In the first stage (overall shear deformation stage), the initial shear modulus is corrected by considering the shear hardening phenomenon: In the formula: This is the initial shear modulus correction value for the first stage (overall shear deformation stage); This is the characterization function for the initial shear modulus correction value in the first stage; This represents the accumulated shear strain in the first stage.

[0040] The second stage (interlayer slip stage) involves correcting the friction angle within the inclusion body considering the frictional softening phenomenon: In the formula: This is the corrected value for shear stress in the second stage (interlayer slip stage); This is the characterization function for the second-stage shear stress correction value; This represents the cumulative shear strain in the second stage.

[0041] S6. Compare the predicted values ​​of the hysteresis curves obtained from the test conditions that were not used for model regression analysis with the hysteresis curves obtained from the test to verify the reliability of the dynamic calculation model. Before predicting the hysteresis curve, it is necessary to determine the normal stress on the sample. Real-time shear deformation x ( t And the limit switch design allows for deformation. First, based on the real-time shear deformation amount x ( t Determine the dynamic shear strain time history of the specimen. Then, the known parameters are substituted into the theoretical model given in step three, and the shear deformation stage of the specimen at different times is determined according to the judgment method given in step two, so as to obtain the dynamic shear stress time history. Finally, the shear stress-shear strain hysteresis curve was determined. The predicted shear stress-shear strain relationship was compared with the experimental results. If it basically conforms to the overall pattern of the experimental data, it can be considered that the model can well describe the deformation law of the confined isolation layer under the action of horizontal seismic inertial force.

[0042] Example 3 This invention provides a method for constructing a dynamic calculation model for a confined seismic isolation cushion layer. Specifically, in this embodiment, a geotextile bag seismic isolation cushion layer is used as the research object. The cushion layer consists of three layers, and the geotextile bag unit size is 40cm×40cm×10cm. The soil inside the bag is filled with natural river sand with a fineness modulus of 2.73 at a 90% filling rate. The bag material is polypropylene geotextile fabric with warp and weft tensile strengths of 47.36kN / m and 44.11kN / m, respectively, and warp and weft tensile elongations of 13.7% and 15.98%, respectively. The specific steps of the method for constructing the dynamic calculation model of the confined geotextile bag seismic isolation cushion layer given in this embodiment are as follows: S1. The cyclic shear tests were conducted with designed normal stresses of 25 kPa, 50 kPa, 100 kPa, and 200 kPa, and designed shear amplitudes of 0.25%, 0.5%, 1%, 2%, and 4%, respectively, with 10 cycles. A control group was established with an unlimited limiter constraint and a pre-designed free deformation of 0 mm for the case with a normal stress of 100 kPa and a shear amplitude of 4%. Four sets of self-made limiter specimens with different horizontal stiffness were used for the tests. The basic parameters of the limiter specimens are shown in Table 1.

[0043] Table 1. Measured stiffness and yield displacement of the limiter S2. Analyze the obtained hysteresis curve morphology. For specimens without limiters, the shear deformation includes the overall shear deformation stage and the interlaminar slip stage. Under the condition of small shear amplitude, the specimen only undergoes overall shear deformation. For specimens with large shear amplitude, the specimen enters the interlaminar slip stage after reaching the maximum static friction force. For specimens with limiters, since the design reserves free deformation amount of 0mm, the limiter deformation has been triggered in the overall shear deformation stage.

[0044] S3. For specimens without limiters, their dynamic model can be directly described using the expressions for the first and second stages; for specimens with limiters, since the limiter deformation is triggered during the test, the limiter shear deformation needs to be accumulated in both the overall shear deformation stage and the interlaminar slip stage. The shear stress in the two stages can be described by the following formulas respectively: S4. First, experimental data from the first cyclic shear test under partial working conditions with the infinitely adjustable device constrained specimen were used for model parameter regression analysis. A relevant solution program was written, and the optimal solution for the model parameters was obtained using the least squares method. This determined the basic material parameters of the specimen used in this experiment, as shown in Table 2. Based on the determined material parameters, the experimental results of the first cyclic shear test under different working conditions can be predicted. Figure 4 , 5 The test and prediction results of shear stress-shear strain hysteresis curves are presented under the conditions of 100 kPa normal stress, overall shear deformation of the specimen without a stopper, and interlaminar slip.

[0045] Table 2 Sample material parameters Secondly, test data from the first cyclic shearing of the specimen constrained by the limiter were used to predict the shear deformation of the specimen under the condition of triggering the deformation of the limiter. Figure 6 The shear deformation test and prediction results of the LD12-R0 model limiter constrained specimen under the conditions of normal stress of 100kPa and shear amplitude of 4%.

[0046] S5. Considering the influence of shear history on the model material parameters, parameter corrections are performed. The experimental data are compiled, and the correction functions to be used are determined as follows: S6. The modified initial shear modulus and friction-like angle are used to predict the experimental conditions not used in the model regression analysis. Figure 7 , 8 The results of cyclic shear deformation tests and predictions were presented under the condition of 100 kPa normal stress, with the specimens constrained by the geotextile exhibiting only overall shear deformation and interlayer slip. The comparison showed that the modified theoretical model can better predict the shear deformation law of the geotextile isolation layer under seismic conditions.

[0047] Example 4 The present invention also provides a dynamic calculation model construction system for a seismic isolation cushion layer. The system is used to implement the method described in Embodiment 1. The system includes: a cyclic shear test module, a stage feature analysis module, a segmented model construction module, a parameter optimization and identification module, a stress correlation modeling module, and a model verification and prediction module. The cyclic shear test module is used to conduct cyclic shear tests on the confined isolation cushion under different stress states. After conversion, the shear stress-shear strain relationship under different working conditions is obtained, that is, the hysteresis curve of the confined isolation cushion. The stage feature analysis module is used to analyze the hysteresis curve morphology of the confined isolation pad under different stress states, and divides it into three stages: overall shear deformation, interlayer slip, and confined device constraint. The segmented model construction module is used to construct the hysteresis curve morphology characteristics of the confined isolation pad at different shear deformation stages using viscoelastic, Coulomb friction and bilinear models respectively, and to determine the theoretical model of the shear stress-shear strain relationship of the confined isolation pad at different shear deformation stages. The parameter optimization and identification module is used to combine the obtained shear stress-shear strain relationship with the theoretical model of the shear stress-shear strain relationship of the confined isolation cushion at different shear deformation stages, and use the least squares method to fit the experimental data to obtain the optimal solution of the parameters of the constructed theoretical model. The stress correlation modeling module is used to perform regression analysis on the relationship between the optimal solution of the constructed theoretical model parameters and the stress state parameters, and to establish a dynamic calculation model of the confined isolation cushion layer based on stress state and considering discontinuous deformation. The model validation and prediction module is used to substitute the stress state parameters corresponding to the test conditions that were not used in the model regression analysis into the constructed dynamic calculation model of the confined isolation cushion layer, so as to predict the shear stress-shear strain relationship at different shear deformation stages.

[0048] In this embodiment, the cyclic shear test module conducts cyclic shear tests on the confined isolation pad under different stress states, and the process of converting the shear stress-shear strain relationship under different working conditions, i.e., the hysteresis curve of the confined isolation pad, includes: ; ; ; In the formula: The calculated dynamic shear stress of the specimen; This refers to the real-time shear force of the loaded plate. The real-time compression ratio of the sample; This represents the initial contact area of ​​the sample. The height at the initial contact moment of the sample; This refers to the real-time height of the sample. γ The calculated dynamic shear strain of the specimen; x This represents the displacement of the upper surface of the sample relative to the lower surface.

[0049] In this embodiment, in the stage feature analysis module, the first stage is the overall shear deformation stage, in which the entire isolation pad undergoes shear deformation; the second stage is the interlayer slip stage, in which any adjacent pads undergo relative slip; and the third stage is the limiter constraint stage, in which the isolation pad comes into contact with the limiter, and the limiter exerts a lateral constraint force on it.

[0050] In this embodiment, the segmented model construction module employs viscoelastic, Coulomb friction, and bilinear models to construct theoretical models for the shear stress-strain relationship of the confined isolation pad at different shear deformation stages, taking into account the hysteresis curve morphology characteristics of the pad at different shear deformation stages. The process of determining these models includes: The nonlinear shear deformation of the cushion layer during the overall shear deformation stage is described using a viscoelastic model, and its dynamic shear stress-shear strain hysteresis curve is expressed as follows: ; In the formula: This refers to the first stage of dynamic shear stress. To unload the instantaneous dynamic shear strain; To unload the instantaneous dynamic shear stress; This is the initial shear modulus; This represents the maximum dynamic shear stress. The influence coefficient of the bag material; The shear stress-shear strain hysteresis curves during the interlayer slip stage are described using the Coulomb friction model: ; In the formula: This refers to the second stage of dynamic shear stress. This represents the displacement of the upper surface of the sample relative to the lower surface. The friction angle of the inclusion body; It is a cohesive force of the inclusion body; The constraint phase of the limit switch is described using a bilinear model: ; ; ; In the formula: This refers to the third stage of dynamic shear stress. The lateral constraint force generated by the limit switch; This refers to the bottom area of ​​the seismic isolation pad. This is the initial stiffness of the limiter; This is the ratio of the stiffness of the limiter after yielding to its initial stiffness; Allowance for free deformation in the design; This is the yield displacement of the limit switch. These are variables that describe the hysteresis characteristics of the limit switch.

[0051] In this embodiment, the process of establishing a dynamic calculation model for a confined isolation cushion layer based on stress state and considering discontinuous deformation by performing regression analysis on the optimal solution of the constructed theoretical model parameters and stress state parameters in the stress correlation modeling module includes: ; ; In the formula: This is the initial shear modulus correction value for the first stage, i.e., the overall shear deformation stage; This is the characterization function for the initial shear modulus correction value in the first stage; This represents the accumulated shear strain in the first stage. This is the shear stress correction value for the second stage, namely the interlayer slip stage; This is the characterization function for the second-stage shear stress correction value; This represents the cumulative shear strain in the second stage.

[0052] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made to the technical solutions of the present invention by those skilled in the art without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for constructing a dynamic calculation model for a seismic isolation layer, characterized in that, The method includes: S1: Conduct cyclic shear tests on the confined isolation pad under different stress states, and obtain the shear stress-shear strain relationship under different working conditions, i.e., the hysteresis curve of the confined isolation pad. S2: The hysteresis curve morphology of the confined isolation pad under different stress states is analyzed and divided into three stages: overall shear deformation, interlayer slip and confined device constraint. S3: Based on the hysteresis curve morphology characteristics of the confined isolation pad at different shear deformation stages, viscoelastic model, Coulomb friction model and bilinear model are used to construct theoretical models of shear stress-shear strain relationship of the confined isolation pad at different shear deformation stages. S4: Combine the obtained shear stress-shear strain relationship with the theoretical model of the shear stress-shear strain relationship of the confined isolation cushion layer at different shear deformation stages, and use the least squares method to fit the experimental data to obtain the optimal solution of the parameters of the constructed theoretical model. S5: Perform regression analysis on the relationship between the optimal solution of the theoretical model parameters and the stress state parameters to establish a dynamic calculation model of the confined isolation cushion layer based on stress state and considering discontinuous deformation; S6: Substitute the stress state parameters corresponding to the test conditions that were not used in the model regression analysis into the constructed dynamic calculation model of the confined isolation cushion layer to predict the shear stress-shear strain relationship at different shear deformation stages.

2. The method according to claim 1, characterized in that, In S1, the method for conducting cyclic shear tests on the confined isolation pad under different stress states and obtaining the shear stress-shear strain relationship under different working conditions, i.e., the hysteresis curve of the confined isolation pad, includes: ； ； ； In the formula: The calculated dynamic shear stress of the specimen; This refers to the real-time shear force of the loaded plate. The real-time compression ratio of the sample; This represents the initial contact area of ​​the sample. The height at the initial contact moment of the sample; This refers to the real-time height of the sample. γ The calculated dynamic shear strain of the specimen; x This represents the displacement of the upper surface of the sample relative to the lower surface.

3. The method according to claim 2, characterized in that, In S2, the first stage is the overall shear deformation stage, in which the entire isolation pad undergoes shear deformation; the second stage is the interlayer slip stage, in which any adjacent pads undergo relative slip; and the third stage is the limiter constraint stage, in which the isolation pad comes into contact with the limiter, and the limiter exerts a lateral constraint force on it.

4. The method according to claim 3, characterized in that, In S3, considering the hysteresis curve morphology characteristics of the confined isolation pad at different shear deformation stages, viscoelastic models, Coulomb friction models, and bilinear models are used to construct theoretical models for the shear stress-shear strain relationship of the confined isolation pad at different shear deformation stages. The methods for determining these models include: The overall shear deformation stage is described by a viscoelastic model, which represents the nonlinear shear deformation of the cushion layer. Its shear stress-strain hysteresis curve is expressed as follows: ； In the formula: This represents the first stage of dynamic shear stress. To unload the instantaneous dynamic shear strain; To unload the instantaneous dynamic shear stress; This is the initial shear modulus; This represents the maximum dynamic shear stress. The influence coefficient of the bag material; The shear stress-shear strain hysteresis curves during the interlayer slip stage are described using the Coulomb friction model: ； In the formula: This refers to the second stage of dynamic shear stress. This represents the displacement of the upper surface of the sample relative to the lower surface. The friction angle of the inclusion body; For the cohesive force of the inclusion, This represents the normal stress experienced by the seismic isolation layer. The constraint phase of the limit switch is described using a bilinear model: ； ； ； In the formula: This refers to the third stage of dynamic shear stress. The lateral constraint force generated by the limit switch; This is the bottom area of ​​the seismic isolation pad. This is the initial stiffness of the limiter; This is the ratio of the stiffness of the limiter after yielding to its initial stiffness; This represents the displacement of the upper surface of the vibration isolation pad relative to the lower surface. Allowance for free deformation in the design; This is the yield displacement of the limit switch. These are variables that describe the hysteresis characteristics of the limit switch.

5. The method according to claim 4, characterized in that, In step S5, the method for establishing a dynamic calculation model of the confined isolation cushion layer based on stress state and considering discontinuous deformation by performing regression analysis on the optimal solution of the constructed theoretical model parameters and stress state parameters includes: ； ； In the formula: This is the initial shear modulus correction value for the first stage, i.e., the overall shear deformation stage; This is the characterization function for the initial shear modulus correction value in the first stage; This represents the accumulated shear strain in the first stage. This is the shear stress correction value for the second stage, namely the interlayer slip stage; This is the characterization function for the second-stage shear stress correction value; This represents the cumulative shear strain in the second stage.

6. A system for constructing a dynamic calculation model for a seismic isolation layer, the system being used to implement the method described in any one of claims 1-5, characterized in that, The system includes: a cyclic shear test module, a stage feature analysis module, a segmented model construction module, a parameter optimization and identification module, a stress correlation modeling module, and a model verification and prediction module; The cyclic shear test module is used to conduct cyclic shear tests on the confined isolation cushion under different stress states, and after conversion, the shear stress-shear strain relationship under different working conditions is obtained, that is, the hysteresis curve of the confined isolation cushion. The stage feature analysis module is used to analyze the hysteresis curve morphology of the confined isolation pad under different stress states, and divides it into three stages: overall shear deformation, interlayer slip, and confined device constraint. The segmented model construction module is used to construct the hysteresis curve morphology characteristics of the confined isolation pad at different shear deformation stages using viscoelastic model, Coulomb friction model and bilinear model respectively, to determine the theoretical model of shear stress-shear strain relationship of the confined isolation pad at different shear deformation stages. The parameter optimization and identification module is used to combine the obtained shear stress-shear strain relationship with the theoretical model of the shear stress-shear strain relationship of the confined isolation cushion layer at different shear deformation stages, and use the least squares method to fit the experimental data to obtain the optimal solution of the parameters of the constructed theoretical model. The stress correlation modeling module is used to perform regression analysis on the relationship between the optimal solution of the constructed theoretical model parameters and the stress state parameters, and to establish a dynamic calculation model of the confined isolation cushion layer based on stress state and considering discontinuous deformation. The model verification and prediction module is used to substitute the stress state parameters corresponding to the test conditions that were not used in the model regression analysis into the constructed dynamic calculation model of the confined isolation cushion layer, so as to predict the shear stress-shear strain relationship at different shear deformation stages.

7. The system according to claim 6, characterized in that, The cyclic shear test module involves conducting cyclic shear tests on the confined isolation cushion under different stress states. The process of converting these tests to obtain the shear stress-shear strain relationship under different working conditions, i.e., the hysteresis curve of the confined isolation cushion, includes: ； ； ； In the formula: The calculated dynamic shear stress of the specimen; This refers to the real-time shear force of the loaded plate. The real-time compression ratio of the sample; This represents the initial contact area of ​​the sample. The height at the initial contact moment of the sample; This refers to the real-time height of the sample. γ The calculated dynamic shear strain of the specimen; x This represents the displacement of the upper surface of the sample relative to the lower surface.

8. The system according to claim 7, characterized in that, In the stage feature analysis module, the first stage is the overall shear deformation stage, in which the entire isolation pad undergoes shear deformation; the second stage is the interlayer slip stage, in which any adjacent pads undergo relative slip; and the third stage is the limiter constraint stage, in which the isolation pad comes into contact with the limiter, and the limiter exerts a lateral constraint force on it.

9. The system according to claim 8, characterized in that, In the segmented model construction module, considering the hysteresis curve morphology characteristics of the confined isolation pad at different shear deformation stages, viscoelastic models, Coulomb friction models, and bilinear models are used to construct the theoretical model for the shear stress-shear strain relationship of the confined isolation pad at different shear deformation stages. The process of determining the theoretical model for the shear stress-shear strain relationship of the confined isolation pad at different shear deformation stages includes: The overall shear deformation stage is described by a viscoelastic model, which represents the nonlinear shear deformation of the cushion layer. Its shear stress-strain hysteresis curve is expressed as follows: ； In the formula: This represents the first stage of dynamic shear stress. To unload the instantaneous dynamic shear strain; To unload the instantaneous dynamic shear stress; This is the initial shear modulus; This represents the maximum dynamic shear stress. The influence coefficient of the bag material; The shear stress-shear strain hysteresis curves during the interlayer slip stage are described using the Coulomb friction model: ； In the formula: This refers to the second stage of dynamic shear stress. This represents the displacement of the upper surface of the sample relative to the lower surface. This refers to the normal stress on the seismic isolation pad. The friction angle of the inclusion body; It is a cohesive force of the inclusion body; The constraint phase of the limit switch is described using a bilinear model: ； ； ； In the formula: This refers to the third stage of dynamic shear stress. The lateral constraint force generated by the limit switch; This is the bottom area of ​​the seismic isolation pad. This is the initial stiffness of the limiter; This is the ratio of the stiffness of the limiter after yielding to its initial stiffness; Allowance for free deformation in the design; This is the yield displacement of the limit switch. These are variables that describe the hysteresis characteristics of the limit switch.

10. The system according to claim 9, characterized in that, In the stress correlation modeling module, the process of performing regression analysis on the optimal solution of the constructed theoretical model parameters and the stress state parameters to establish a dynamic calculation model of the confined isolation cushion layer based on stress state and considering discontinuous deformation includes: ； ； In the formula: This is the initial shear modulus correction value for the first stage, i.e., the overall shear deformation stage; This is the characterization function for the initial shear modulus correction value in the first stage; This represents the accumulated shear strain in the first stage. This is the shear stress correction value for the second stage, namely the interlayer slip stage; This is the characterization function for the second-stage shear stress correction value; This represents the cumulative shear strain in the second stage.

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