Microdynamic analysis method of asphalt pavement damage under tire-road coupling

Abstract

The present invention relates to a mesodynamic analysis method for asphalt pavement damage under tire-road coupling. The method comprises: respectively using a linear model, a Burgers model, and an improved Burgers model to represent the connections between aggregate-aggregate, mortar-mortar, and aggregate-mortar, wherein each model contains unknown mesoparameters; after deducing the macro-mesoparameter conversion relationship of the three models using Newton's second law and force balance theory, the unknown mesoparameters of each model are determined through an indoor asphalt creep test to obtain a viscoelastic multi-layer pavement model; constructing a flexible discrete element tire model, and constructing a mesodynamic model of a flexible tire-road coupling system based on the flexible discrete element tire model and the viscoelastic multi-layer pavement model; and analyzing the mesodynamics of asphalt pavement damage under tire-road coupling based on the mesodynamic model of the tire-road coupling system. The method is simple and highly accurate.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle-road coupling dynamics, and in particular to a microscopic dynamics analysis method of asphalt pavement damage under tire-road coupling. Background Art

[0002] Urban roads are a crucial component of urban planning and construction, and a crucial driving force behind urban economic development. The more developed a city, the more developed its urban roads are, reflecting its development and modernization progress to a significant extent. Expressways offer advantages such as high economic returns, eased traffic pressure, and improved transportation structure.

[0003] Asphalt pavement damage, such as cracks, potholes, rutting, and bumps, is becoming increasingly prominent. These problems pose a serious threat to vehicle safety and increase pavement maintenance costs. Therefore, research on asphalt pavement damage under tire-road coupling is needed.

[0004] However, current research on tire-road coupling systems is mostly limited to the perspective of macroscopic mechanics. Studies on the dynamic response of coupled systems make it difficult to explain the complex dynamic development of coupled systems, from material changes to structural changes. Furthermore, research on microscopic damage to asphalt pavement mixtures is mostly limited to the specimen scale, often simplifying the effect of the tire on the pavement as a moving load. This makes it impossible to accurately describe the actual stress state of the asphalt pavement under tire-road coupling, resulting in poor results when applied to actual engineering projects. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a microscopic dynamic analysis method for asphalt pavement damage under tire-road coupling.

[0006] In order to solve the above problems, the technical solution adopted by the present invention is:

[0007] A microscopic dynamic analysis method for asphalt pavement damage under tire-road coupling, the method comprising:

[0008] Step 1: Use linear model, Burgers model and improved Burgers model to represent the connection between aggregate-aggregate, mortar-mortar and aggregate-mortar respectively, where each model contains unknown microscopic parameters;

[0009] Step 2: After deriving the macro-micro parameter conversion relationship of the three models using Newton's second law and force balance theory, the unknown micro parameters of each model were determined through indoor asphalt creep tests to obtain a viscoelastic multi-layer pavement model;

[0010] Step 3: construct a flexible discrete element tire model, and construct a microscopic dynamic model of the flexible tire-road coupling system based on the flexible discrete element tire model and the viscoelastic multi-layer pavement model.

[0011] As an embodiment of the invention, in step 1:

[0012] The constitutive equation of the linear model is:

[0013] F n =K n u n ;

[0014] F s =K s u s ;

[0015] Among them, F s and F n are the forces acting on the contact point along the tangential and normal directions respectively; K s and K n are the stiffness in the tangential and normal directions respectively; u s and u n are the displacements of the contact point along the tangential and normal directions, respectively;

[0016] The constitutive equation of the Burgers model is:

[0017]

[0018]

[0019]

[0020]

[0021] in, and are the displacements of the spring and damper along the normal direction in the Maxwell model; and are the displacements of the spring and damper along the tangential direction in the Maxwell model; u kn and u ks are the displacements of the Kelvin model along the normal and tangential directions respectively;

[0022] The constitutive equation of the improved Burgers model is:

[0023]

[0024]

[0025]

[0026] Among them, K mn and K ms are the normal and tangential stiffness of the Maxwell part of the model respectively; C mn and C ms are the normal and tangential damping of the Maxwell part of the model; K kn and K ks are the normal and tangential stiffness of the Kelvin part of the model respectively; C kn and C ks are the normal and tangential damping of the Kelvin part of the model respectively; and is the stiffness of aggregate A in the tangential and normal directions; and are the normal and tangential stiffnesses of the Maxwell part of mortar B, respectively; and are the normal and tangential damping of the Maxwell part of mortar B, respectively; and are the normal and tangential stiffness of the Kelvin part of mortar B, respectively; and are the normal and tangential damping of the Kelvin component of mortar B, respectively.

[0027] As an embodiment of the invention, the step 2 includes:

[0028] S201. Use Newton's second law and force balance theory to deduce the unknown microscopic parameters K of the linear model s The transformation relationship between the aggregate macroscopic parameters E and ν' is as follows:

[0029]

[0030]

[0031] Where G is the shear modulus of the aggregate, E is the Young's modulus, and ν' is the Poisson's ratio of the aggregate;

[0032] S202. Use Newton's second law and force balance theory to derive the unknown microscopic parameter K of the Burgers model mn , K ms 、C mn 、C ms , K kn , K ks 、C kn 、C ks The conversion relationship between the mortar macro parameters E1, E2, η1, η2, and ν is as follows:

[0033] K mn =E1t;C mn =η1t;K kn =E2t;C kn =η2t;

[0034]

[0035] Among them, E1 and E2 are Young's modulus of mortar, η1 and η2 are viscosity of mortar, and ν is Poisson's ratio of mortar;

[0036] S202. Use Newton's second law and force balance theory to derive the unknown microscopic parameter K of the improved Burgers model mn , K ms 、C mn 、C ms , K kn , K ks 、C kn 、C ks The conversion relationship between the mortar macro parameters E1, E2, η1, η2, and ν is as follows:

[0037]

[0038]

[0039] Among them, E1 and E2 are Young's modulus of mortar, η1 and η2 are viscosity of mortar, and ν is Poisson's ratio of mortar;

[0040] Step S204: Obtain E and ν' of the aggregate, obtain E1, E2, η1, η2, and ν of the mortar through indoor asphalt creep tests, and substitute them into the transformation equations of steps S201 to S203 to determine the unknown microscopic parameters of each model, thereby obtaining a viscoelastic multi-layer pavement model.

[0041] As an embodiment of the present invention, in step 3, the flexible discrete element tire model is constructed using the following method:

[0042] The discrete element method is used to discretize the actual tire into several particles. The particles are connected by springs and dampers. Newton's second law is applied to calculate the motion state of the particles and the contact force between the particles, and a flexible discrete element tire model is constructed.

[0043] As an embodiment of the invention, after constructing the flexible discrete element tire model, step three further includes: performing a tire static stiffness test to determine the accuracy of the flexible discrete element tire model;

[0044] The method specifically includes adjusting the stiffness and damping parameters of the discrete element tire particles, calculating multiple theoretical deformations of the tire under load, comparing the multiple theoretical deformations with the corresponding multiple actual deformations obtained in the tire static stiffness test, and determining the accuracy of the flexible discrete element tire model.

[0045] As an embodiment of the invention, in step three, a microscopic dynamic model of the tire-road coupling system is constructed based on the flexible discrete element tire model and the viscoelastic multi-layer pavement model, including:

[0046] A microscopic dynamic model of a flexible tire-road coupling system is established based on the flexible discrete element tire model and the viscoelastic multi-layer pavement model. The properties and parameters of the microscopic dynamic model of the flexible tire-road coupling system are consistent with those of the flexible discrete element tire model and the viscoelastic multi-layer pavement model. During the construction process, corresponding code is written using the Fish language so that the contact formed by the tire with the mortar and coarse aggregate of the pavement layer during rolling is linear contact with the same parameters.

[0047] As an embodiment of the invention, step three further includes:

[0048] Indoor rutting tests are conducted to modify and verify the microscopic dynamic model of the tire-road coupling system until the microscopic dynamic model of the tire-road coupling system meets the simulation accuracy.

[0049] As an embodiment of the invention, the method further includes:

[0050] Step 4: Based on the microscopic dynamic model of the tire-road coupling system, a parameter analysis is performed on the microscopic model of the viscoelastic pavement under the action of the tire and road to study the influence of aggregate movement, internal contact force changes and permanent deformation of the mixture when the temperature, vehicle speed and vehicle weight change.

[0051] The beneficial effects of adopting the above technical solution are:

[0052] The present invention provides a micro-dynamic analysis method for asphalt pavement damage under tire-road coupling. It couples the tire and pavement models from the perspective of micro-mechanics, and uses the tire as the load on the pavement. Compared with existing research methods that simplify the effect of the tire on the pavement as a moving load, this method can more accurately describe the complex contact relationship between the tire and the road. In addition, Newton's second law is used to calculate the motion state and contact force changes between particles in the pavement asphalt mixture under tire-road coupling, and then the rutting evolution process from micro-material changes to the formation of macro-permanent deformation is studied, thereby improving the accuracy of the results. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1This is a flow chart of a microscopic dynamic analysis method for asphalt pavement damage under tire-road coupling provided by the present invention.

[0054] Figure 2 This is a technical roadmap provided by the present invention.

[0055] Figure 3 This is a schematic diagram of a linear connection model provided by the present invention (wherein (a) is a normal connection and (b) is a tangential connection).

[0056] Figure 4 It is an improved Burgers model provided by the present invention (wherein (a) is a normal connection and (b) is a tangential connection).

[0057] Figure 5 This is a schematic diagram of a Burgers creep model provided by the present invention (wherein (a) is a normal connection and (b) is a tangential connection).

[0058] Figure 6 This is a schematic diagram of particle connection mechanical analysis provided by the present invention.

[0059] Figure 7 This is a schematic diagram of a macro Burgers model provided by the present invention.

[0060] Figure 8 This is a creep test curve and fitting curve diagram provided by the present invention (wherein (a) is SBS-13 modified asphalt, and (b) is ARSH-20 rubber powder asphalt).

[0061] Figure 9 This is a comparison diagram of tire static stiffness curves provided by the present invention.

[0062] Figure 10 This is a schematic diagram of a tire and bridge deck pavement coupling system provided by the present invention.

[0063] Figure 11 This is a comparison diagram of indoor rutting test and virtual test results provided by the present invention (wherein (a) is rutting depth and (b) is dynamic stability). DETAILED DESCRIPTION

[0064] In order to make the objectives, technical solutions and advantages of the present invention more clear, the invention is described clearly and completely below in conjunction with specific embodiments.

[0065] The embodiment of the present invention provides a microscopic dynamic analysis method for asphalt pavement damage under tire-road coupling, such as Figure 1 and Figure 2 As shown, the method includes:

[0066] Step S1: linear model, Burgers model and improved Burgers model are used to represent the connection between aggregate-aggregate, mortar-mortar and aggregate-mortar respectively, wherein each model contains unknown microscopic parameters.

[0067] This step is based on an asphalt pavement model established according to the gradation and porosity of the asphalt mixture. When performing a microscopic analysis, the present invention divides the asphalt mixture into aggregate and mortar according to its composition, wherein the connection relationships between aggregate-aggregate, mortar-mortar, and aggregate-mortar are as follows.

[0068] Aggregate-aggregate can be used as follows Figure 3 The connection relationship of the linear connection model shown in Figure 3 As shown, the constitutive equation of the linear model is:

[0069] F n =K n u n ;

[0070] F s =K s u s ;

[0071] Among them, F s and F n are the forces acting on the contact point along the tangential and normal directions respectively; K s and K n are the stiffness in the tangential and normal directions respectively; u s and u n are the displacements of the contact point along the tangential and normal directions, respectively. The unknown microscopic parameters of the linear model are K s .

[0072] Mortar-mortar can be used as follows Figure 4 The connection relationship of the Burgers creep model shown in Figure 4 As shown, the constitutive equation of the Burgers model is:

[0073]

[0074]

[0075]

[0076]

[0077] in, and are the displacements of the spring and damper along the normal direction in the Maxwell model; and are the displacements of the spring and damper along the tangential direction in the Maxwell model; u kn and u ks are the displacements of the Kelvin model along the normal and tangential directions, and the unknown microscopic parameter K of the Burgers model. mn , K ms 、C mn 、C ms , K kn , K ks 、C kn 、C ks .

[0078] Aggregate-mortar can be used as follows Figure 5 The connection relationship of the improved Burgers model shown in Figure 5 As shown, the constitutive equation of the improved Burgers model is:

[0079]

[0080]

[0081]

[0082] Among them, K mn and K ms are the normal and tangential stiffness of the Maxwell part of the model respectively; C mn and C ms are the normal and tangential damping of the Maxwell part of the model; K kn and K ks are the normal and tangential stiffness of the Kelvin part of the model respectively; C kn and C ks are the normal and tangential damping of the Kelvin part of the model respectively; and is the stiffness of aggregate A in the tangential and normal directions; and are the normal and tangential stiffnesses of the Maxwell part of mortar B, respectively; and are the normal and tangential damping of the Maxwell part of mortar B, respectively; and are the normal and tangential stiffness of the Kelvin part of mortar B, respectively; and are the normal and tangential damping of the Kelvin part of mortar B respectively; the unknown microscopic parameter of the improved Burgers model is K mn , K ms 、C mn 、Cms , K kn , K ks 、C kn 、C ks .

[0083] Step S2: After deriving the macro-micro parameter conversion relationship of the three models using Newton's second law and force balance theory, the unknown micro parameters of each model are determined through indoor asphalt creep tests to obtain a viscoelastic multi-layer pavement model.

[0084] Usually in the elastic connection modeling process of the discrete element method, the contact between two discrete elements can be regarded as an elastic beam with both ends located at the center of the discrete element, such as Figure 6 As shown, there are corresponding forces and moments acting at the center of each discrete element. The mechanical simplification of the viscoelastic connection is similar to that of the elastic connection, and the elastic beam is replaced by a viscoelastic beam.

[0085] The length L, width W and height H of the beam can be expressed as

[0086] L=W=R A +R B ;H=t;

[0087] Among them, R A and R B are the radii of particles A and B, respectively. t can be set via the command stream in PFC2D. From this, the area A and moment of inertia I of the contact beam can be calculated using the following equations.

[0088]

[0089] Step S201 (for linear model): Figure 3 and Figure 6 The normal force F can be written as n The expression is as follows:

[0090]

[0091] Where E is the Young's modulus of the material; A is the area of ​​the elastic beam; K n is the connection stiffness between particles; ε and ΔL are the strain and relative displacement of the elastic beam, respectively.

[0092] From the above formula we can deduce:

[0093] Similarly, the microscopic parameter K can also be derived s The transformation relationship between the aggregate macroscopic parameters E and ν' is as follows:

[0094]

[0095]

[0096] Where G is the shear modulus of the aggregate, E is the Young's modulus, and ν' is the Poisson's ratio of the aggregate.

[0097] Step S202 (for Burgers model): Under axial stress, the macroscopic mechanical behavior of asphalt mortar can be Figure 7 The Burgers model in Figure 4 and Figure 7 The unknown microscopic parameter K of the Burgers model is derived using Newton's second law and force balance theory. mn , K ms 、C mn 、C ms , K kn , K ks 、C kn 、C ks The conversion relationship between the mortar macro parameters E1, E2, η1, η2, and ν is as follows:

[0098] K mn =E1t;C mn =η1t;K kn =E2t;C kn =η2t;

[0099]

[0100] Among them, E1 and E2 are Young's modulus of mortar, η1 and η2 are viscosity of mortar, and ν is Poisson's ratio of mortar.

[0101] Step S203 (for improving the Burgers model): according to Figure 3 and Figure 4 The connection models between aggregates and between mortars are both two particles. Finally, the stiffness and damping of the connection spring are half of the particle spring and damping. Newton's second law and force balance theory are used to derive the unknown microscopic parameters K of the improved Burgers model. mn , K ms 、C mn 、C ms , K kn , K ks 、C kn 、C ks The conversion relationship between the mortar macro parameters E1, E2, η1, η2, and ν is as follows:

[0102]

[0103]

[0104] Among them, E1 and E2 are Young's modulus of mortar, η1 and η2 are viscosity of mortar, and ν is Poisson's ratio of mortar.

[0105] Step S204: After obtaining E1, E2, η1, η2, and ν of the mortar through indoor asphalt creep testing, substitute them into the conversion equations of steps S201 to S203 to determine the unknown microscopic parameters of each model, thereby obtaining a viscoelastic multi-layer pavement model.

[0106] The E and ν' of the aggregate can be obtained by referring to the values ​​in other public documents, or by referring to the test methods disclosed in other public documents for testing, which is not specifically limited in the present invention.

[0107] The E1, E2, η1, η2, and ν of the mortar were obtained by performing an indoor asphalt creep test using a dynamic shear rheometer. The indoor asphalt creep test adopted an equal stress loading method and set the loading stress to 50 kPa. The creep equation can be written as:

[0108]

[0109] Where J(t) is the creep compliance; ε(t) is the strain; σ0 is the loading stress; E1 and η1 are the stiffness coefficient and viscosity coefficient of the Maxwell part of the Burgers model, respectively; E2 and η2 are the stiffness coefficient and viscosity coefficient of the Kelvin part of the Burgers model, respectively.

[0110] The stiffness and viscosity of the aggregate in the asphalt mixture are fixed values ​​and do not change with temperature. Therefore, a creep curve of the creep compliance including the stiffness and viscosity of the asphalt mortar over time can be obtained by conducting a creep test on the paving asphalt mortar at a certain temperature. The data is then fitted to obtain E1, E2, η1, η2, and ν of the mortar. The values ​​are substituted into the conversion formula of steps S201 to S203 to determine the unknown microscopic parameters of each model, thus obtaining a viscoelastic multi-layer paving model.

[0111] For example, a bridge deck in a certain project is paved with two layers of asphalt mixture: SMA-13 ​​modified asphalt mixture and ARSH-20 rubber asphalt mixture. The creep test of the two asphalt mortars at 60°C is carried out and the test data are fitted. The test curve and fitting curve are detailed in Figure 8 The macroscopic parameters E1, E2, η1, η2 and ν of the mortar in the Burgers model are obtained through fitting.

[0112] Step S3: constructing a flexible discrete element tire model, and constructing a microscopic dynamic model of a flexible tire-road coupling system based on the flexible discrete element tire model and the viscoelastic multi-layer pavement model.

[0113] This step includes:

[0114] Step S301: Using the discrete element method, the actual tire is discretized into a number of particles. The particles are connected by springs and dampers. Newton's second law is applied to calculate the motion state of the particles and the contact force between the particles, thereby constructing a flexible discrete element tire model.

[0115] Step S302: Perform a tire stiffness test to verify the accuracy of the flexible discrete element tire model;

[0116] The method specifically includes adjusting the stiffness and damping parameters of the discrete element tire particles, calculating multiple theoretical deformations of the tire under load, comparing the multiple theoretical deformations with the corresponding multiple actual deformations obtained in the tire static stiffness test, and determining the accuracy of the flexible discrete element tire model.

[0117] For example, the static stiffness test of the heavy-duty radial tire 10.00R20 was conducted in the present invention. The deformation value calculated by the flexible discrete element tire model under the vertical static load was compared with the static stiffness indoor test data of the tire. Figure 9 As shown in the graph, it can be seen that the calculated results are in good agreement with the experimental results, indicating that the discrete element tire model established in this paper can simulate the actual tire stress characteristics and can be used for tire-road coupled microscopic dynamics calculations.

[0118] Step S303: Establish a microscopic dynamic model of the flexible tire-road coupling system based on the flexible discrete element tire model and the viscoelastic multi-layer pavement model, such as Figure 10 The properties and parameters of the flexible tire-road coupling system's microdynamic model are consistent with those of the flexible discrete element tire model and the viscoelastic multilayer pavement model. These properties include the asphalt mixture's gradation and void ratio, and the parameters include the asphalt mixture's stiffness and viscosity, as well as the tire's stiffness. During the construction process, corresponding code was written using the Fish language to ensure that the tire's rolling contact with the various mortar and coarse aggregate layers in the pavement is linear contact with identical parameters.

[0119] The force transmitted by the tire to the surface layer is achieved through the microscopic contact forces between the tire particles and the pavement layer. The tire axial force is a coupled dynamic tire force that accounts for road surface irregularities. To avoid varying contact stiffness between the tire and the mortar and coarse aggregate during rolling, code was developed using the Fish language to ensure that all contact surfaces formed by the tire with the mortar and coarse aggregate in the pavement layer are linear contacts with identical parameters.

[0120] Step S304: Perform an indoor rutting test to correct and verify the microscopic dynamics model of the tire-road coupling system until the microscopic dynamics model of the tire-road coupling system meets the simulation accuracy.

[0121] The specific steps include:

[0122] According to the provisions and steps of the "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering" (JTG E20-2011), a double-layer pavement rutting specimen was made. The rutting and dynamic stability at 60°C were obtained, and the tire-road micro-model was continuously adjusted until the calculated results were in good agreement with the test results. Figure 11 As shown in Figure 3, in this case, the numerical model is considered correct and can be used to study the damage behavior of asphalt pavement under tire-road coupling.

[0123] Step S4: analyzing the mesodynamics of asphalt pavement damage under tire-road coupling based on the tire-road coupling system mesodynamics model.

[0124] It includes: parameter analysis of the microscopic model of viscoelastic pavement under the action of tire and road, studying the influence of aggregate movement, internal contact force changes and permanent deformation of the mixture when the temperature, vehicle speed and vehicle weight change, exploring the rutting process from microscopic material changes to macroscopic permanent deformation, and then revealing the rutting evolution mechanism from material damage to structural damage.

Claims

1. A microscopic dynamic analysis method for asphalt pavement damage under tire-road coupling, characterized by: The method comprises: Step 1: Use linear model, Burgers model and improved Burgers model to represent the connection between aggregate-aggregate, mortar-mortar and aggregate-mortar respectively, where each model contains unknown microscopic parameters; Step 2: After deriving the macro-micro parameter conversion relationship of the three models using Newton's second law and force balance theory, the unknown micro parameters of each model were determined through indoor asphalt creep tests to obtain a viscoelastic multi-layer pavement model; Step 3: constructing a flexible discrete element tire model, and constructing a microscopic dynamic model of a flexible tire-road coupling system based on the flexible discrete element tire model and the viscoelastic multi-layer pavement model; The method further comprises: Step 4: Based on the microscopic dynamic model of the tire-road coupling system, a parameter analysis is performed on the microscopic model of the viscoelastic pavement under the interaction of the tire and road to study the influence of temperature changes, vehicle speed, and vehicle weight on the movement of aggregates, changes in contact forces within the mixture, and permanent deformation; In step 3, a microscopic dynamic model of the tire-road coupling system is constructed based on the flexible discrete element tire model and the viscoelastic multi-layer pavement model, including: A microscopic dynamic model of a flexible tire-road coupling system is established based on the flexible discrete element tire model and the viscoelastic multi-layer pavement model. The properties and parameters of the microscopic dynamic model of the flexible tire-road coupling system are consistent with those of the flexible discrete element tire model and the viscoelastic multi-layer pavement model. During the construction process, corresponding code is written using the Fish language so that the contact formed by the tire with the mortar and coarse aggregate of the pavement layer during rolling is linear contact with the same parameters.

2. The micro-dynamic analysis method of asphalt pavement damage under tire-road coupling according to claim 1 is characterized in that: In step one: The constitutive equation of the linear model is: F n =K n u n ; F s =K s u s ; Among them, F s and F n are the forces acting on the contact point along the tangential and normal directions respectively; K s and K n are the stiffness in the tangential and normal directions respectively; u s and u n are the displacements of the contact point along the tangential and normal directions, respectively; The constitutive equation of the Burgers model is: in, and are the displacements of the spring and damper along the normal direction in the Maxwell model; and are the displacements of the spring and damper along the tangential direction in the Maxwell model; u kn and u ks are the displacements of the Kelvin model along the normal and tangential directions respectively; The constitutive equation of the improved Burgers model is: Among them, K mn and K ms are the normal and tangential stiffness of the Maxwell part of the model respectively; C mn and C ms are the normal and tangential damping of the Maxwell part of the model; K kn and K ks are the normal and tangential stiffness of the Kelvin part of the model respectively; C kn and C ks are the normal and tangential damping of the Kelvin part of the model respectively; and is the stiffness of aggregate A in the tangential and normal directions; and are the normal and tangential stiffnesses of the Maxwell part of mortar B, respectively; and are the normal and tangential damping of the Maxwell part of mortar B, respectively; and are the normal and tangential stiffness of the Kelvin part of mortar B, respectively; and are the normal and tangential damping of the Kelvin component of mortar B, respectively.

3. The microscopic dynamic analysis method of asphalt pavement damage under tire-road coupling according to claim 2 is characterized in that: The second step includes: S201. Use Newton's second law and force balance theory to deduce the unknown microscopic parameters K of the linear model s The transformation relationship between the aggregate macroscopic parameters E and ν' is as follows: Wherein, G is the shear modulus of the aggregate, E is the Young's modulus, v' is the Poisson's ratio of the aggregate; A is the area of ​​the elastic beam; L is the length of the elastic beam; t is the height of the elastic beam. The elastic beam is a beam with both ends located at the center of the discrete element in the elastic connection modeling process of the discrete element method. S202. Use Newton's second law and force balance theory to derive the unknown microscopic parameter K of the Burgers model mn , K ms 、C mn 、C ms , K kn , K ks 、C kn 、C ks The conversion relationship between the mortar macro parameters E1, E2, η1, η2, and v is as follows: K mn =E1t;C mn =η1t;K kn =E2t;C kn =η2t; Among them, E1 and E2 are Young's modulus of mortar, η1 and η2 are viscosity of mortar, and v is Poisson's ratio of mortar; S203. Use Newton's second law and force balance theory to derive the unknown microscopic parameter K of the improved Burgers model mn , K ms 、C mn 、C ms , K kn , K ks 、C kn 、C ks The conversion relationship between the mortar macro parameters E1, E2, η1, η2, and v is as follows: C mn =2η1t;K kn =2E2t;C kn =2η2t; Among them, E1 and E2 are Young's modulus of mortar, η1 and η2 are viscosity of mortar, and v is Poisson's ratio of mortar; Step S204: Obtain E and vˊ of the aggregate, obtain E1, E2, η1, η2, and v of the mortar through indoor asphalt creep tests, and substitute them into the transformation equations of steps S201 to S203 to determine the unknown microscopic parameters of each model, thereby obtaining a viscoelastic multi-layer pavement model.

4. The microscopic dynamic analysis method of asphalt pavement damage under tire-road coupling according to claim 1 is characterized in that: In step 3, the flexible discrete element tire model is constructed using the following method: The discrete element method is used to discretize the actual tire into several particles. The particles are connected by springs and dampers. Newton's second law is applied to calculate the motion state of the particles and the contact force between the particles, and a flexible discrete element tire model is constructed.

5. The microscopic dynamic analysis method of asphalt pavement damage under tire-road coupling according to claim 4 is characterized in that: After constructing the flexible discrete element tire model, step three also includes: performing a tire static stiffness test to determine the accuracy of the flexible discrete element tire model; The method specifically includes adjusting the stiffness and damping parameters of the discrete element tire particles, calculating multiple theoretical deformations of the tire under load, comparing the multiple theoretical deformations with the corresponding multiple actual deformations obtained in the tire static stiffness test, and determining the accuracy of the flexible discrete element tire model.

6. The micro-dynamic analysis method of asphalt pavement damage under tire-road coupling according to claim 1 is characterized in that: Step three also includes: Indoor rutting tests are conducted to modify and verify the microscopic dynamic model of the tire-road coupling system until the microscopic dynamic model of the tire-road coupling system meets the simulation accuracy.

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