Multi-physics coupling pavement structure analysis method based on orthogonal vector function system

Abstract

The invention provides a multi-physics field coupling pavement structure analysis method based on an orthogonal vector function system. According to the method, a random dynamic load function of a whole vehicle model is defined, a layered pavement model is established, the orthogonal vector function system is introduced, and an analytical solution of a coupling field acting pavement problem is deduced by using a DVP (Dual Volume Method) transfer method. The random dynamic load function is obtained by using a filtering white noise method to establish pavement unevenness excitation and carrying out simulation solution on the whole vehicle model. The layered pavement model is a saturated porous thermoelastic layered body established according to a fluid thermosetting theory. The orthogonal vector function system converts the road surface problem basic control equation into an ordinary differential equation. The DVP method is an improved transfer matrix method, and transfer matrixes between different layers of the pavement structure can be obtained. The analytic solution is calculated by using a boundary condition. According to the method, the positive index term of e in the matrix is eliminated, the calculation efficiency and accuracy are improved, a more stable analysis method is provided for solving the problem of the layered body of the pavement, the three factors of the vehicle load, the temperature and the water are comprehensively considered, and the complex environment and the stress condition of the pavement structure in actual use are more truly reflected.

Description

Technical Field

[0001] The invention relates to a multi-physical field coupled pavement structure analytical method based on an orthogonal vector function system, which can solve the mechanical response problem of the pavement structure under the vehicle-water-temperature coupling effect. Background Art

[0002] Traditional pavement structure analysis mainly focuses on the study of a single physical field, such as stress field, temperature field, and hydraulic field. However, in actual road use, road performance is always affected by multiple physical fields at the same time, such as changes in pavement mechanical response caused by temperature changes, mechanical deformation caused by vehicle loads, and material aging caused by water penetration. The interactions between these factors are complex, and the analysis method of a single physical field cannot fully reflect the complex environment and stress conditions of the pavement structure in actual use.

[0003] As modern infrastructure construction places increasing demands on safety and durability, it is essential to study the response of pavement structures under the combined effects of multiple physical fields. Multi-physics coupling analysis can more realistically reflect the actual conditions of pavement structures, which is of great significance for extending road service life, reducing maintenance costs, and ensuring traffic safety. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a multi-physical field coupled pavement structure analytical method based on an orthogonal vector function system in view of the deficiencies of the prior art. The road surface roughness excitation is established using the filtered white noise method, and the random dynamic load of the whole vehicle model is obtained by simulation. This random dynamic load is used as the load of the vehicle on the road surface. According to the fluid-thermal-solid theory, a layered pavement model under the action of the temperature-water-vehicle coupling field is established. By introducing an orthogonal vector function system and using the DVP (Dual variable and position method) transfer method, an analytical solution to the pavement problem under the action of the coupling field is derived, and an analytical solution expression of the temperature, hydraulic, and stress field response is given to realize the multi-physical field coupled analytical solution of the pavement structure. This method can more accurately analyze the pavement structure problem under the joint action of multiple factors.

[0005] The technical solution adopted by the present invention to solve the technical problem is: a multi-physical field coupled pavement structure analysis method based on an orthogonal vector function system, comprising the following steps:

[0006] Step 1: Use the filtered white noise method to establish a road roughness excitation model, establish a four-wheel vehicle model based on the excitation model, and define the random dynamic load function of the vehicle model;

[0007] The excitation model is represented by formula (1):

[0008]

[0009] In formula (1), are the left front, right front, left rear and right rear wheel excitation models respectively, q 1 (t), q 2 (t), q 3 (t), q 4 (t) are the time domain functions of the left front, right front, left rear and right rear wheel unevenness, respectively, n 0 is the reference spatial frequency, n q is the cutoff spatial frequency in the road space, G q (n 0 ) is the road roughness coefficient, ω(t) is the standard Gaussian white noise signal, v is the vehicle speed, B f is the distance between the front wheels of the vehicle, t d is the lag time, t d =L / v, L is the vehicle wheelbase;

[0010] The vehicle model assumes:

[0011] 1) Horizontal vibration of the model is not considered;

[0012] 2) The model does not hang in the air and the wheels remain in contact with the road surface;

[0013] 3) The wheel damping coefficient is not considered;

[0014] The random dynamic load function F j (t) As represented by formula (2), the random dynamic load includes a static load and an additional dynamic load, and the random dynamic load can be fitted as a superposition of a series of simple harmonic loads with different amplitudes, frequencies and phases;

[0015]

[0016] In formula (2), a and b are the distances from the front and rear overhangs to the center of mass, respectively, m b is the vehicle body mass, m j is the wheel mass, g is the acceleration due to gravity, k tj is the elastic stiffness of the wheel, z j is the vertical displacement of the wheel, q j is the wheel excitation from road roughness, Re is the real part, P l ,ω l ,θ l are the amplitude, angular frequency and phase of the harmonic load respectively, t is time, i is the imaginary unit, j = 1, 2, 3, 4.

[0017] Step 2: Assume a pavement structure model, define the constitutive relationship expression of the thermal-fluid-solid coupling effect, the generalized Darcy law, the generalized Fourier law, the fluid balance equation, and the energy conservation equation; based on the above theoretical equations, the basic control equations of the pavement structure model with thermal-fluid-solid coupling can be obtained; the boundary conditions and interlayer bonding conditions of the pavement model are given;

[0018] The constitutive relation expression is represented by formula (3):

[0019]

[0020] In formula (3), σ ij is the stress component function, ε ij is the strain component, μ and λ are the Lame constants, e 0 is the volumetric strain, δ ij is the delta function, β q is the thermal modulus of the medium, q is the absolute temperature, K b is the solid phase bulk modulus of the medium under drainage conditions, K s is the bulk modulus of the solid phase of the medium, and p is the pore water pressure;

[0021] The generalized Darcy law is represented by equation (4):

[0022]

[0023] In formula (4), ψ is the fluid velocity vector, k is the permeability coefficient, μ w is the kinematic viscosity of the fluid, ▽p is the saturated pore water pressure gradient, ρ f is the fluid density, g is the gravity vector, g z Take 9.8m / s 2 , D q is the water flow diffusion rate under the action of temperature gradient, ▽q is the temperature gradient;

[0024] The generalized Fourier law is represented by equation (5):

[0025] γ h =-K▽q+D P ▽p (5),

[0026] In formula (5), γ h is the heat flux vector, K is the thermal conductivity coefficient, ▽q is the temperature gradient, D p is the heat flow diffusivity of the pore water pressure gradient, ▽p is the saturated pore water pressure gradient;

[0027] The fluid balance equation is represented by equation (6):

[0028]

[0029] In formula (6), γ w is the density of the fluid, k is the permeability coefficient, α u is the linear expansion coefficient of the material, q is the temperature function, e 0 is the volume strain, S p is the poroelastic water release coefficient of the medium, p is the pore water pressure, ρ w is the pore water density;

[0030] The energy conservation equation is represented by equation (7):

[0031]

[0032] In formula (7), K is the thermal conductivity, q is the temperature function, h is the overall specific heat capacity of the half space, β q is the thermal modulus of the medium, T 0 is the initial temperature, e 0 is the volume strain;

[0033] The basic control equations include the stress-strain equation under the influence of multi-field coupling, the structural motion balance equation of the saturated thermoelastic layered body problem, the heat flux density and temperature function equation along the one-dimensional depth direction, the energy conservation equation of multi-field coupling, the fluid flow velocity and pore pressure equation along the one-dimensional depth direction, and the pore water seepage balance equation considering the influence of temperature;

[0034] The boundary condition is represented by equation (8), where the bottom layer of the layered body is a half-space infinite body;

[0035]

[0036] In formula (8), σ zz , σ rz and σ θz is the surface stress, F s It is the circular simple harmonic load on the road surface at a certain moment in the vertical direction, and its amplitude is P 1 , F s =P 1 / πR 2 , R is the radius of the circular load, q is the temperature, p t is the pavement temperature change function, p is the pore water pressure, p d is the dynamic water pressure;

[0037] The interlayer bonding condition is that any interlayer interface in the layered body is completely continuous.

[0038] Step 3: Using the superposition principle, write the vehicle random load as the superposition of multiple simple harmonic loads. By analyzing the pavement response under each simple harmonic load separately, the final response is the superposition of all results.

[0039] Step 4: define an orthogonal vector function system, derive the basic form of the expression of all mechanical responses in the saturated thermoelastic layered half-space problem under the vector function coefficients, and sort out the ordinary differential equations about the response coefficients. The present invention only considers the axisymmetric deformation of m=0;

[0040] The orthogonal vector function is represented by equation (9):

[0041]

[0042] In formula (9), e r , e θ , e z are the unit vectors of the r, θ, and z axes in the cylindrical coordinate system, S is a scalar function, and the variables ξ and m are the transformed variables of r and θ in the vector function system;

[0043] The expression is represented by formula (10):

[0044]

[0045] In formula (10), f is the physical domain response function, and F is the conversion domain response function;

[0046] The ordinary differential equation system is represented by equation (11):

[0047]

[0048] In formula (11), U=[U L ,U M ,H,Ψ] t , T=[T L ,T M ,Q,P] t , M is the coefficient matrix of the LM part, U L and U M is the expansion coefficient of the displacement component integral transformation, T L and T M is the expansion coefficient of stress component integral transformation, H is the heat flux vector, Ψ is the pore water velocity, Q is the temperature function, and P is the pore water pressure;

[0049] The non-zero elements of the coefficient matrix M in formula (11) are represented by formula (12):

[0050]

[0051] In formula (12), μ and λ are Lamé constants, ξ and m are transformation domain variables, β q is the thermal modulus of the medium, β p is the Boit consolidation coefficient, T 0is the absolute temperature, v is the Poisson's ratio of the material, i is the imaginary unit, h is the overall specific heat capacity of the half space, K is the thermal conductivity, γ w is the density of the fluid, α u is the linear expansion coefficient of the material, k is the permeability coefficient, ρ s is the density of the solid material, n 1 is the medium porosity;

[0052] Step 5: Derive the transfer relationship between different layers of the pavement structure based on the DVP method;

[0053] The DVP method is an improved transfer matrix method, which uses vector coefficients to form the state vector of each structural layer, adopts the method of cross-transfer of displacement and stress vector function coefficients, eliminates the positive exponential term of e in the matrix, and constructs an inter-layer transfer matrix containing only negative exponential terms;

[0054] The transfer matrix is ​​represented by equation (13):

[0055]

[0056] In formula (13), A is a layered body z 0 Layer (surface) to z n Coefficient matrix of the transfer matrix between layers (bottom).

[0057] Step 6: Calculate and obtain the analytical solution, and perform calculation and analysis on the mechanical response of the pavement structure;

[0058] The calculation is to obtain the vector coefficient of the pavement surface by using the boundary conditions, and to obtain the mechanical response vector coefficient at any position of the pavement layered structure based on the interlayer transfer relationship. Substituting the vector coefficient into equation (10) can obtain the analytical solution of the mechanical response of the pavement structure under the temperature-water-vehicle coupling effect.

[0059] The analytical solution is the vertical displacement u represented by equation (14): z and stress ε zz For example:

[0060]

[0061] In formula (14), F s is the load in the vertical direction of the road surface, R is the radius of the circular simple harmonic load, μ and λ are the Lame constants, β q is the thermal modulus of the medium, β p is the Boit consolidation coefficient, Iteg i mov is numerical integration, i = 1, 2, 3, 6, 8;

[0062] The mechanical response calculation is to obtain all mechanical responses under the action of harmonic loads with multiple different amplitudes, frequencies, and phases at any position of the pavement structure by using analytical solutions, and finally the sum of all values is the required mechanical response;

[0063] The mechanical response analysis includes using analytical solutions to analyze the differences in mechanical responses of pavement layered bodies under different field theories, analyzing the influence of load moving speed on the pavement structure, obtaining the variation diagrams of displacement, stress, and strain with the load moving speed, and completing the analysis of the pavement structure under the coupling action of multiple physical fields.

[0064] Compared with the existing technologies, the advantages of the present invention are as follows:

[0065] 1. The present invention provides an analytical method for a multi-physical-field coupled pavement structure based on an orthogonal vector function system, which can simultaneously consider the combined effects of temperature, water, and vehicle loads. This method can more truly reflect the complex environment and stress conditions of the pavement structure in actual use than traditional single-physical-field studies.

[0066] 2. The present invention adopts an improved transfer matrix method - the DVP method, which eliminates the positive exponential terms of e in the matrix and constructs an interlayer transfer matrix containing only negative exponential terms, improving the calculation efficiency and accuracy.

[0067] 3. The present invention introduces an orthogonal vector function system and uses the DVP transfer method to derive the analytical solutions of pavement problems under the action of the coupled field, and gives the specific expressions of temperature, hydraulic, and stress field responses. This method can more accurately analyze the pavement structure problems under the combined action of multiple factors. Description of the Drawings

[0068] Figure 1 is the flow chart of the method of the present invention;

[0069] Figure 2 is the vehicle model diagram in the embodiment of the present invention;

[0070] Figure 3 is the variation of the displacement u z response amplitude with the load moving speed at different layer positions below the origin in the embodiment of the present invention;

[0071] Figure 4 is the stress ε zz response amplitude with the load moving speed at different layer positions below the origin in the embodiment of the present invention;

[0072] Figure 5 is the variation of the vertical displacement response amplitude at different layer positions below the origin for different pavement layered bodies in the embodiment of the present invention;

[0073] Figure 6The variation of strain response amplitudes of different pavement layer bodies at different layers below the origin in the embodiment of the present invention; DETAILED DESCRIPTION

[0074] like Figure 1 As shown, the multi-physics field coupled pavement structure analysis method based on the orthogonal vector function system in this embodiment is performed according to the following steps:

[0075] Step 1: Use the filtered white noise method to establish a road roughness excitation model, establish a four-wheel vehicle model based on the excitation model, and define the random dynamic load function of the vehicle model;

[0076] The incentive model is represented by formula (1):

[0077]

[0078] In formula (1), are the left front, right front, left rear and right rear wheel excitation models respectively, q 1 (t), q 2 (t), q 3 (t), q 4 (t) are the time domain functions of the left front, right front, left rear and right rear wheel unevenness, respectively, n 0 is the reference spatial frequency, n q is the cutoff spatial frequency in the road space, G q (n 0 ) is the road roughness coefficient, ω(t) is the standard Gaussian white noise signal, v is the vehicle speed, B f is the distance between the front wheels of the vehicle, t d is the lag time, t d =L / v, L is the vehicle wheelbase;

[0079] Vehicle model assumptions:

[0080] 1) Horizontal vibration of the model is not considered;

[0081] 2) The model does not hang in the air and the wheels remain in contact with the road surface;

[0082] 3) The wheel damping coefficient is not considered;

[0083] Random dynamic load function F j (t) is represented by formula (2). The random dynamic load includes static load and additional dynamic load. Using the superposition principle, the random dynamic load is fitted as a superposition of a series of simple harmonic loads with different amplitudes, frequencies and phases:

[0084]

[0085] In formula (2), a and b are the distances from the front and rear overhangs to the center of mass, respectively, mb is the vehicle body mass, m j is the wheel mass, g is the acceleration due to gravity, k tj is the elastic stiffness of the wheel, z j is the vertical displacement of the wheel, q j is the wheel excitation from road roughness, Re is the real part, P l ,ω l ,θ l are the amplitude, angular frequency and phase of the harmonic load, respectively, t is time, i is the imaginary unit, j = 1, 2, 3, 4;

[0086] In the specific implementation, based on formula (1), Simulink is used to establish Figure 2 The four-wheel vehicle model shown acts on a layered asphalt pavement. The vehicle parameters adopt the Granada real vehicle model. Finally, the random load at each wheel is solved by simulation.

[0087] Step 2: Assuming the pavement structure model, the basic control equations of the pavement structure model with thermal-fluid-solid coupling are obtained based on the theoretical equations, and the boundary conditions and interlayer bonding conditions of the pavement model are given:

[0088] The pavement structure model assumes that:

[0089] 1) The layered asphalt pavement under the influence of multi-field coupling is a multi-layer saturated thermoelastic layered half-space;

[0090] 2) The hydraulic field and temperature field follow Darcy's law and Fourier's law;

[0091] 3) Random dynamic loads acting on the surface;

[0092] The basic control equations include the stress-strain equation under the influence of multi-field coupling represented by equation (3), the structural motion equilibrium equation of the saturated thermoelastic layered body problem represented by equation (4), the heat flux density and temperature function equation along the one-dimensional depth direction represented by equation (5), the energy conservation equation of multi-field coupling represented by equation (6), the fluid flow velocity and pore pressure equation along the one-dimensional depth direction represented by equation (7), and the pore water seepage equilibrium equation considering the influence of temperature represented by equation (8):

[0093]

[0094] In formula (3), σ ij ' is the function of each stress component of effective stress, σ ij '=σ ij -β p p-β q q,σ ij is the stress component function, ε ij is the strain component, βp is the Biot effective stress parameter, which can be directly taken as 1, β q is the thermal modulus of the medium, q is the absolute temperature, p is the pore water pressure, μ and λ are the Lame constants, e 0 is the volume strain;

[0095]

[0096] In formula (4), σ ij is the stress component, u i is the displacement component, r, θ and z are the coordinate vectors in the cylindrical coordinate system, ρ s is the density of the solid material, n 1 is the medium porosity;

[0097]

[0098] In formula (5), γ is the heat flux, K is the thermal conductivity, and q is the temperature function;

[0099]

[0100] In formula (6), q is the temperature function, h is the overall specific heat capacity of the half space, K is the thermal conductivity, β q is the thermal modulus of the medium, T 0 is the initial temperature, e 0 is the volume strain;

[0101]

[0102] In formula (7), ψ is the fluid velocity, k is the permeability coefficient, and p is the pore water pressure;

[0103]

[0104] In formula (8), γ w is the density of the fluid, k is the permeability coefficient, α u is the linear expansion coefficient of the material, q is the temperature function, e 0 is the volume strain, p is the pore water pressure;

[0105] The boundary conditions are represented by equation (9), where the bottom layer of the layered body is an infinite half-space body;

[0106]

[0107] In formula (9), σ zz , σ rz and σ θz is the surface stress, F s It is the circular simple harmonic load on the road surface at a certain moment in the vertical direction, and its amplitude is P 1 , Fs =P 1 / πR 2 , R is the radius of the circular load, q is the temperature, p t is the pavement temperature change function, p is the pore water pressure, p d is the dynamic water pressure;

[0108] The interlayer bonding condition is that any interlayer interface in the layered body is completely continuous;

[0109] In specific implementation, according to the effective stress principle and Hooke's law, the stress-strain equation under the influence of multi-field coupling is obtained from the constitutive relationship expression; the inertia of the fluid and the influence of body force are ignored, and the structural motion equilibrium equation of the saturated thermoelastic layered body problem is obtained; according to the generalized Fourier law, without considering the Dufour effect, the relationship between the heat flux density and the temperature function along the one-dimensional depth direction is obtained; according to the energy conservation equation, the energy conservation equation of multi-field coupling can be obtained; according to the generalized Darcy law, without considering the Soret-like effect, the fluid flow velocity and pore pressure equation along the one-dimensional depth direction are obtained; according to the fluid balance equation, the influence of solid compressibility and inertia of the structural fluid in the structure is ignored, and the pore water seepage equilibrium equation considering the influence of temperature is obtained.

[0110] Step 3: Using the superposition principle, write the vehicle random load as the superposition of multiple simple harmonic loads. By analyzing the road surface response under each simple harmonic load separately, the final response is the superposition of all results.

[0111] In the specific implementation, the random load of each wheel is fitted into a series of simple harmonic loads, the road surface response under each simple harmonic load is calculated, and the results are superimposed and summed to obtain the final response; taking the left front wheel load of the whole vehicle model as an example, the vibration frequency of 0.5-30Hz is selected, and the random load is decomposed into the superposition of multiple harmonic loads with different amplitudes, frequencies and phases. When l is 0, ω 0 =0Hz,θ 0 =0rad、P 0 =G 1 , represents the static load part of the vehicle.

[0112] Step 4: define an orthogonal vector function system, derive the basic form of the expression of all mechanical responses in the saturated thermoelastic layered half-space problem under the vector function coefficients, and sort out the ordinary differential equations about the response coefficients. The present invention only considers the axisymmetric deformation of m=0;

[0113] The orthogonal vector function is represented by equation (10):

[0114]

[0115] In formula (10), e r , eθ , e z are the unit vectors of the r, θ, and z axes in the cylindrical coordinate system, S is a scalar function, and the variables ξ and m are the transformed variables of r and θ in the vector function system;

[0116] The basic form of the expression is represented by formula (11):

[0117]

[0118] In formula (11), f is the physical domain response function, and F is the conversion domain response function;

[0119] In the specific implementation, the displacement, stress, pore water pressure, temperature, water flow rate, and heat flux density response functions in the problem are introduced into the orthogonal vector function system represented by equation (10), and the basic form of the expression of all mechanical responses in the saturated thermoelastic layered half-space problem under the vector function coefficients is obtained;

[0120] The ordinary differential equation system is represented by equation (12):

[0121]

[0122] In formula (12), U=[U L ,U M ,H,Ψ] t , T=[T L ,T M ,Q,P] t , M is the coefficient matrix of the LM part, U L and U M is the expansion coefficient of the displacement component integral transformation, T L and T M is the expansion coefficient of stress component integral transformation, H is the heat flux vector, Ψ is the pore water velocity, Q is the temperature function, and P is the pore water pressure;

[0123] The non-zero elements of the coefficient matrix M in formula (12) are represented by formula (13):

[0124]

[0125] In formula (13), μ and λ are Lamé constants, ξ and m are transformation domain variables, β q is the thermal modulus of the medium, β p is the Boit consolidation coefficient, T 0 is the absolute temperature, v is the Poisson's ratio of the material, i is the imaginary unit, h is the overall specific heat capacity of the half space, K is the thermal conductivity, γ w is the density of the fluid, α u is the linear expansion coefficient of the material, k is the permeability coefficient, ρ s is the density of the solid material, n1 is the medium porosity;

[0126] In specific implementation, after importing the L, M and N function systems, the solution to the asphalt pavement problem under the coupling of temperature, moving load and pore water is converted into solving the LM part of the independent ordinary differential equations about the vector function coefficients. The order of the coefficient matrix of the LM part of the equations is 8th order.

[0127] Step 5: Derive the transfer relationship between different layers of the pavement structure based on the DVP method;

[0128] The DVP method is an improved transfer matrix method, which uses vector coefficients to form the state vector of each structural layer, adopts the method of cross-transfer between displacement and stress vector function coefficients, eliminates the positive exponential term of e in the matrix, and constructs an inter-layer transfer matrix containing only negative exponential terms.

[0129] The transfer matrix is ​​represented by equation (14):

[0130]

[0131] In formula (14), A is a layered body z 0 Layer (surface) to z n Coefficient matrix of the transfer matrix between layers (bottom).

[0132] In the specific implementation, write the general solution of the LM part of the ordinary differential equation system, construct the j-layer (the upper and lower interfaces are z j-1 and z j ) is the general solution expression of the coefficient at the upper and lower interfaces. j-1 To interface z j The cross-construction coefficient state vector is derived from the interface z j-1 To interface z j Repeat the above operation to obtain the transfer relationship expression from the surface to the bottom of the layered body under completely continuous conditions.

[0133] Step 6: Calculate and obtain the analytical solution, and perform calculation and analysis on the mechanical response of the pavement structure;

[0134] In specific implementation, the vector coefficient of the pavement surface is obtained by using the boundary conditions, and the mechanical response vector coefficient at any position of the pavement layered structure is obtained based on the interlayer transfer relationship. The vector coefficient is substituted into equation (11) to obtain the analytical solution of the mechanical response of the pavement structure under the coupling of temperature, water and vehicle.

[0135] The analytical solution is the vertical displacement u represented by equation (15): z and stress ε zz For example:

[0136]

[0137] In Equation (15), F s is the load acting in the vertical direction of the road surface, R is the acting radius of the circular harmonic load, μ and λ are Lame constants, β q is the thermal modulus of the medium, β p is the Boit consolidation coefficient, Iteg i mov is the numerical integration, i = 1, 2, 3, 6, 8;

[0138] The calculation of the mechanical response is to obtain all the mechanical responses under the action of harmonic loads with multiple different amplitudes, frequencies and phases at any position of the pavement structure by using the analytical solution, and finally the sum of all values is the required mechanical response;

[0139] The analysis of the mechanical response includes the analysis of the differences in the mechanical responses of the pavement layer under different field theories by using the analytical solution, the analysis of the influence of the load moving speed on the pavement structure, obtaining the variation diagrams of displacement, stress and strain with the load moving speed, and completing the analysis of the pavement structure under the coupling action of multiple physical fields.

Claims

1. A multi-physics field coupled pavement structure analytical method based on an orthogonal vector function system, the method defines a random dynamic load function of a whole vehicle model, establishes a layered pavement model, introduces an orthogonal vector function system, and uses a DVP (Dual variable and position method) transfer method to derive an analytical solution to the pavement problem under the action of a coupled field. The random dynamic load function is obtained by using a filtered white noise method to establish a pavement unevenness excitation, and the whole vehicle model is simulated and solved. The layered pavement model is a saturated porous thermoelastic layered body established according to the fluid-thermo-solid theory. The orthogonal vector function system converts the basic control equation of the pavement problem into an ordinary differential equation. The DVP method is an improved transfer matrix method, which can obtain the transfer matrix between different layers of the pavement structure. The method eliminates the positive exponential term of e in the matrix, improves the calculation efficiency and accuracy, and provides a more stable analytical method for solving the pavement layered body problem. It comprehensively considers the three factors of vehicle load, temperature and water, and more truly reflects the complex environment and stress conditions of the pavement structure in actual use.

2. The multi-physics field coupled pavement structure analysis method based on orthogonal vector function system according to claim 1 is characterized by: The method defines a random dynamic load function of a whole vehicle model, establishes a layered pavement model, introduces an orthogonal vector function system, and uses a DVP transfer method to derive an analytical solution to a pavement problem under coupled field action.

3. The multi-physics field coupled pavement structure analysis method based on orthogonal vector function system according to claim 1 is characterized by: The random dynamic load function is obtained by using a filtered white noise method to establish road surface roughness excitation and simulating and solving a whole vehicle model.

4. The multi-physics field coupled pavement structure analysis method based on orthogonal vector function system according to claim 1 is characterized by: The layered pavement model is a saturated porous thermoelastic layered body established according to the fluid-thermo-solid theory.

5. The multi-physics field coupled pavement structure analysis method based on orthogonal vector function system according to claim 1 is characterized by: The orthogonal vector function system transforms the basic control equation of the road surface problem into an ordinary differential equation.

6. The multi-physics field coupled pavement structure analysis method based on orthogonal vector function system according to claim 1 is characterized by: The DVP method is an improved transfer matrix method, which can obtain the transfer matrix between different layers of the pavement structure.

7. The multi-physics field coupled pavement structure analysis method based on orthogonal vector function system according to claim 1 is characterized by: The analytical solution is obtained by calculation using boundary conditions, and the required mechanical response can be solved as needed.

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