Evaluation method for ruts on asphalt pavement of creeping heavy traffic road section

Abstract

The invention discloses an asphalt pavement rut evaluation method for a creeping heavy-load traffic road section, which comprises the following steps of: firstly, investigating the traffic volume of the creeping heavy-load traffic road section, and converting into standard axle load action times; then, according to a real asphalt pavement structure, determining a structure size required by simulation and the thickness of each layer, establishing a three-dimensional model after checking standard literatures to obtain material parameters, and endowing attributes with the three-dimensional model; defining a material behavior as creep deformation, inputting parameters, calculating a temperature field, and importing the temperature field into the model; determining the contact area of the tire and the road surface, and determining the creep analysis step duration according to the standard axle load; then applying a vertical vehicle load and boundary conditions, and performing grid division, calculation and analysis on the model to obtain vertical and transverse displacement values; and providing a rut evaluation method for the crawling heavy traffic road section according to a calculation result. The evaluation method provided by the invention has a certain guiding effect on the proportion optimization design and economic rationality design of the asphalt mixture of the asphalt pavement.

Description

Technical Field

[0001] The present invention relates to the field of road engineering, and in particular to a method for evaluating rutting on asphalt pavement in creeping heavy-load traffic sections. Background Art

[0002] As the highway network expands, road maintenance becomes increasingly demanding. Urban sections with heavy traffic experience frequent braking and starting, severe traffic channeling, and prolonged vehicle stoppages, significantly different from other sections. Numerous studies have shown that asphalt pavement is particularly susceptible to rutting when heavy vehicles travel slowly and repeatedly accelerate and decelerate, due to surges in horizontal forces and increased static pressure time, combined with persistent high temperatures.

[0003] The current high-temperature rutting resistance design system for asphalt mixtures primarily relies on a single metric, dynamic stability, as an evaluation criterion. However, extensive engineering practice demonstrates that even when the mixture meets regulatory requirements, pavement rutting frequently occurs on roads subject to creeping, heavy traffic. Conventional rutting tests for asphalt mixtures are conducted at 60°C and 0.7 MPa, which are inconsistent with the actual operating conditions on high-temperature, heavy-load roads. Furthermore, the modified asphalt concrete used in these tests often exhibits only a primary deformation of 1-2 mm, failing to achieve true rutting damage and failing to reflect long-term rutting resistance.

[0004] Most of the existing rutting evaluation methods are suitable for ordinary road sections with uniform speed driving, and do not take into account problems such as frequent braking and starting of vehicles on creeping and heavy-loaded traffic sections. Therefore, there is an urgent need for a rutting evaluation method for asphalt pavement on creeping and heavy-loaded traffic sections to solve the problem of rutting being easily generated on creeping and heavy-loaded traffic sections. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for evaluating rutting of asphalt pavement in creeping heavy-load traffic sections, so as to solve the problem that rutting is easily generated in creeping heavy-load traffic sections.

[0006] To achieve the above object, the present invention provides a method for evaluating rutting on asphalt pavement in a creeping heavy-load traffic section, comprising the following steps:

[0007] S10. Conduct a traffic volume survey based on the creeping heavy-load traffic section to obtain the total traffic volume for the entire day and the traffic volume ratio per hour, and convert the actual traffic load into the number of standard axle load actions;

[0008] S20. Determine the structural dimensions and layer thickness of the asphalt pavement required for simulation based on the asphalt pavement structure; obtain asphalt pavement material parameters by consulting specifications and literature; establish a three-dimensional asphalt pavement model based on the structural dimensions of the asphalt pavement and assign material properties; define the material behavior of the asphalt pavement material as creep;

[0009] S30, inputting asphalt road material parameters into the asphalt road three-dimensional model; calculating the temperature field of the asphalt pavement structure at high temperature, and importing the calculated temperature field into the asphalt road three-dimensional model;

[0010] S40, determining the contact area between the tire and the asphalt pavement during road braking, and determining the creep analysis step length based on the number of standard axle load applications; applying a vertical vehicle load to the asphalt road three-dimensional model, and applying boundary conditions to the asphalt road three-dimensional model;

[0011] S50, meshing the asphalt road three-dimensional model and performing calculation and analysis to ultimately obtain the vertical rutting displacement value of the asphalt road in the creeping heavy-load traffic section;

[0012] S60. By analyzing the effects of high temperature, heavy load and low speed on asphalt roads, a method for evaluating asphalt pavement rutting in creeping heavy load traffic sections is proposed.

[0013] Preferably, the expression for converting the actual traffic load into the number of standard axle load actions in S10 is as follows:

[0014]

[0015] Where N 等效 Indicates the number of times the standard axle load acts, P i represents the actual axle weight of the i-th type axle, P 标准 Indicates the standard axle load specified in the specification, such as 100kN for a single-axle double-wheel set and 0.7Mpa ground pressure, N i It represents the number of times the i-th type of axis acts, and n represents the damage index (usually 4 to 5 for asphalt pavement).

[0016] Preferably, the asphalt road material parameters in S20 include heat flux density q, thermal conductivity k, rebound modulus E, temperature T, Poisson's ratio μ and creep material parameters, and the creep material parameters include power multiplication law A, equivalent stress order n, and time order m; the established three-dimensional asphalt road model includes: creating components, selecting the model space as three-dimensional, selecting the model type as deformable, selecting the shape as solid, and finally assigning the model material parameters.

[0017] Preferably, in S30, the material behavior of the asphalt road material is defined as creep, wherein the creep deformation ε of the asphalt road is cr It is a function of temperature T, stress q and time t, and the expression is as follows:

[0018] ε cr =f(T,q,t);

[0019] If the stress q is kept constant during analysis, the expression of the time hardening creep model is:

[0020]

[0021] in, is the uniaxial equivalent creep strain rate, the power multiplication law A, the equivalent stress order n, and the time order m are model parameters;

[0022] When calculating the temperature field of asphalt pavement structure, for multi-layer materials, the temperature field distribution of each layer is obtained according to Fourier's heat conduction law:

[0023]

[0024] T surfrace is the road surface temperature; h i is the thickness of the i-th layer; k i is the thermal conductivity of the i-th layer; q is the heat flux density.

[0025] Preferably, the process of determining the contact area between the tire and the asphalt road surface during road braking in S40 and determining the creep analysis step length according to the number of standard axle load actions is as follows:

[0026] Calculate the contact area A between the tire and the asphalt road surface during road braking using the following expression:

[0027] A=LB;

[0028]

[0029] Where B is the tire contact width in cm, L is the tire contact length in cm, δ is the axle load distribution coefficient (light braking increases the front axle load by 10%-15%; moderate braking increases the front axle load by 17%-25%; extreme braking increases the front axle load by 28%-37%), P is the vehicle axle weight in kN, n w is the number of wheels on the axle, in pieces, and p is the tire ground pressure, in MPa;

[0030] The creep analysis step length is determined based on the number of standard axle load actions. The creep analysis step length is set to the cumulative load action time. The calculation expression for the cumulative load action time is as follows: For normal driving sections, the calculation expression for the cumulative load action time is as follows:

[0031]

[0032] Where, t is the cumulative action time of wheel load, in seconds; v is the initial speed at braking, in km / h; B is the tire contact width, in cm; P is the vehicle axle weight, in kN; n w is the number of wheels on the axle, in units of pieces; N is the number of times the wheel load acts, in units of times; p is the tire ground pressure, in units of MPa;

[0033] Considering the braking situation, the calculation expression of the cumulative load action time is as follows:

[0034]

[0035] Where a is the absolute value of acceleration during braking; t is the cumulative action time of wheel load, in seconds; B is the tire contact width, in cm; P is the vehicle axle weight, in kN; n w is the number of wheels on the axle, in units of pieces; N is the number of times the wheel load acts, in units of times; p is the tire ground pressure, in units of MPa; δ is the axle load distribution coefficient.

[0036] Preferably, the boundary conditions imposed on the asphalt road three-dimensional model in S40 are specifically: normal constraints are applied to the four sides of the asphalt road three-dimensional model, and X, Y, and Z constraints are applied to the bottom.

[0037] Preferably, according to the results calculated in S40, the effects of high temperature, heavy load and low speed on asphalt roads are analyzed, and according to the analysis and calculation results, new dynamic stability experimental conditions are proposed, including experimental temperature, wheel load size, and number of round-trip rolling times. Finally, a method for evaluating rutting of asphalt pavement in creeping heavy-load traffic sections under the new experimental conditions is proposed.

[0038] Therefore, the present invention proposes a method for evaluating creeping heavy-load traffic sections, which has the following beneficial effects:

[0039] (1) Considering the special working conditions of creeping heavy-load traffic sections, a rutting evaluation method for asphalt pavement in creeping heavy-load traffic sections is proposed.

[0040] (2) Use numerical models for verification and analysis: Considering the relationship between actual traffic volume and numerical calculation, a three-dimensional asphalt pavement structure is established, and the development law of asphalt pavement rutting under high temperature, heavy load, low speed and braking conditions is calculated and analyzed to verify the rationality of the evaluation method.

[0041] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 This is a flow chart of a method for evaluating vertical rutting on asphalt pavement in creeping heavy-load traffic sections according to the present invention;

[0043] Figure 2 A schematic diagram of a three-dimensional model of an asphalt road according to an embodiment of the present invention;

[0044] Figure 3 Schematic diagram of temperature field calculation results of a three-dimensional model of an asphalt road in a city crawling heavy-load traffic section at a high temperature moment according to an embodiment of the present invention;

[0045] Figure 4This is a schematic diagram of the calculation results of the vertical displacement of the rutting of a three-dimensional model of an asphalt road in a creeping heavy-load traffic section under high temperature conditions on a certain day according to an embodiment of the present invention;

[0046] Figure 5 This is a cross-sectional view of the pavement structure according to an embodiment of the present invention. DETAILED DESCRIPTION

[0047] The following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort shall fall within the scope of protection of the present invention.

[0048] See also Figure 1-Figure 5 The method for evaluating rutting of asphalt pavement in creeping heavy-load traffic sections includes the following steps:

[0049] S10. Conduct a traffic volume survey based on a real creeping heavy-load traffic section to obtain the total traffic volume for the entire day and the traffic volume ratio per hour. Convert the actual traffic load into the number of standard axle loads. The specific expression is as follows:

[0050]

[0051] Where N 等效 Indicates the number of times the standard axle load acts, P i represents the actual axle weight of the i-th type axle, P 标准 Indicates the standard axle load specified in the specification, such as 100kN for a single-axle double-wheel set and 0.7Mpa ground pressure, N i It represents the number of times the i-th type of axis acts, and n represents the damage index (usually 4 to 5 for asphalt pavement).

[0052] S20. Determine the structural dimensions and layer thickness of the asphalt road required for simulation based on the actual asphalt road structure; obtain asphalt road material parameters by consulting specifications and literature; establish a three-dimensional model of the asphalt road based on the structural dimensions of the asphalt road and assign material properties; at the same time, define the material behavior of the asphalt road material as creep; among them, the asphalt road material parameters include heat flux density q, thermal conductivity k, rebound modulus E, temperature T, Poisson's ratio μ and creep material parameters, and the creep material parameters include power multiplication law A, equivalent stress order n, and time order m; the established three-dimensional asphalt road model includes: creating components, selecting the model space as three-dimensional, selecting the model type as deformable, selecting the shape as solid, and finally assigning the model material parameters.

[0053] S30, inputting asphalt road material parameters into the asphalt road three-dimensional model; wherein the creep deformation ε of the asphalt road crIt is a function of temperature T, stress q and time t, and the expression is as follows:

[0054] ε cr =f(T,q,t);

[0055] If the stress q is kept constant during analysis, the expression of the time hardening creep model is:

[0056]

[0057] in, is the uniaxial equivalent creep strain rate, the power multiplication law A, the equivalent stress order n, and the time order m are model parameters.

[0058] Calculate the temperature field of the asphalt road structure and import the calculated temperature field into the asphalt road 3D model; for multi-layer materials, according to Fourier's heat conduction law, obtain the temperature field distribution of each layer:

[0059]

[0060] T surfrace is the road surface temperature; h i is the thickness of the i-th layer; k i is the thermal conductivity of the i-th layer; q is the heat flux density.

[0061] S40, determining the contact area between the tire and the asphalt road surface during road braking, and determining the creep analysis step length based on the number of standard axle load actions; the specific process is as follows:

[0062] Calculate the contact area A between the tire and the asphalt road surface during road braking using the following expression:

[0063] A=LB;

[0064]

[0065] Where B is the tire contact width in cm, L is the tire contact length in cm, δ is the axle load distribution coefficient (light braking increases the front axle load by 10%-15%; moderate braking increases the front axle load by 17%-25%; extreme braking increases the front axle load by 28%-37%), P is the vehicle axle weight in kN, n w is the number of wheels on the axle, in pieces, and p is the tire ground pressure, in MPa;

[0066] The creep analysis step length is determined based on the number of standard axle load actions. The creep analysis step length is set to the cumulative load action time. For normal driving sections, the calculation expression for the cumulative load action time is as follows:

[0067]

[0068] Where, t is the cumulative action time of wheel load, in seconds; v is the initial speed at braking, in km / h; B is the tire contact width, in cm; P is the vehicle axle weight, in kN; n w is the number of wheels on the axle, in units of pieces; N is the number of times the wheel load acts, in units of times; p is the tire ground pressure, in units of MPa;

[0069] Considering the braking situation, the calculation expression of the cumulative load action time is as follows:

[0070]

[0071] Where a is the absolute value of acceleration during braking; t is the cumulative action time of wheel load, in seconds; B is the tire contact width, in cm; P is the vehicle axle weight, in kN; n w is the number of wheels on the axle, in units of pieces; N is the number of times the wheel load acts, in units of times; p is the tire ground pressure, in units of MPa; δ is the axle load distribution coefficient.

[0072] Apply vertical vehicle loads to the asphalt road 3D model, and apply boundary conditions to the asphalt road 3D model. Specifically, the boundary conditions applied to the asphalt road 3D model include: applying normal constraints on all sides of the asphalt road 3D model, and applying X, Y, and Z constraints on the bottom.

[0073] S50. Meshing the asphalt road three-dimensional model and performing calculation and analysis to finally obtain the vertical rutting displacement value of the asphalt road in the creeping heavy-load traffic section.

[0074] S60. Based on the calculation results, the effects of high temperature, heavy load and low speed on asphalt roads are analyzed, and a method for evaluating asphalt pavement rutting in creeping heavy load traffic sections is proposed.

[0075] Implementation Cases:

[0076] Single-layer slab model verification: Taking an indoor rutting experiment as an example, the structural dimensions are: 300mm*300mm*50mm, and the material is SBS modified asphalt concrete AC-13.

[0077]

[0078] The error between the experimental mean and the simulation value is basically small, and the model is reasonable.

[0079] S10. First, conduct a traffic volume survey based on a real-world, heavy-load, and creeping traffic section. Based on axle weight, the traffic volume can be categorized as follows: small passenger cars with a 2-ton axle weight account for 70%; medium trucks (6-ton axle weight) account for 15%; heavy trucks with a 10-ton axle weight account for 10%; and buses with a 14-ton axle weight account for 5%. For a city with a creeping, heavy-load traffic section, the daily traffic volume is 10,000. The calculated traffic volume for each axle weight is: small passenger cars: 7,000; medium trucks: 1,500; heavy trucks: 1,000; and buses: 500.

[0080] The actual traffic volume is converted into the number of standard axle load actions according to the axle load. The calculation formula is as follows:

[0081]

[0082] The number of standard axle load effects converted from passenger car traffic volume is 11.2; the number of standard axle load effects converted from medium-sized truck traffic volume is 194.4; the number of standard axle load effects converted from heavy truck traffic volume is 1000; the number of standard axle load effects converted from bus traffic volume is 1920.8; the total equivalent standard axle load effects are 3126.4.

[0083] The traffic volume ratio per hour is obtained through investigation, and the traffic ratio of each time period is obtained based on the ratio. The cumulative action time is calculated based on S50 to obtain the values ​​in Table 1:

[0084] Table 1

[0085]

[0086]

[0087] S20. Determine the required asphalt pavement structural dimensions and layer thicknesses based on the actual asphalt pavement structure. Obtain asphalt pavement material parameters by consulting specifications and literature. Based on the structural dimensions, create a 3D asphalt pavement model with a width of 1.5 meters, a height of 3 meters, and a longitudinal length of 2.13 meters. First, create the component, select 3D as the model space, select Deformable as the model type, select Solid as the shape, and finally assign material properties. Also, define the material behavior of the asphalt pavement as creep.

[0088] The material parameters of asphalt pavement are shown in Tables 2 and 3.

[0089] Table 2

[0090]

[0091]

[0092] Table 3

[0093] Material Rebound modulus E / Mpa Poisson's ratio Cement-stabilized gravel 1200 0.2 lime soil 300 0.3 soil base 45 0.4

[0094] S30. Input the asphalt road material parameters into the asphalt road three-dimensional model; calculate the temperature field of the asphalt pavement structure and import it into the finite element model. The calculation results are shown in Table 4 and Table 5.

[0095] Table 4

[0096] Asphalt layer Cement-stabilized gravel lime soil soil base Thermal conductivity 1.2-1.7 0.8-1.5 0.5-1.2 0.4-1.0

[0097] Table 5

[0098] Road surface temperature 50℃ Road surface temperature 60℃ Road surface temperature 70℃ Asphalt layer bottom temperature 46.70℃ 55.6℃ 64.5℃ Cement stabilized gravel bottom temperature 38.47℃ 44.63℃ 50.79℃ Lime soil bottom temperature 20℃ 20℃ 20℃

[0099] S40. Determine the contact area between the tire and the asphalt pavement during road braking, and determine the creep analysis step length based on the number of standard axle load applications. When performing a three-dimensional analysis of asphalt pavement rutting, since the actual contact shapes between the wheel and the pavement are rectangular and two semicircular, to simplify the calculation, it can be further simplified to a rectangular load. The calculation formula is:

[0100]

[0101] Where, the vehicle axle load is 100KN, 140KN, and 200KN, the number of wheels on the axle is 4, the tire contact pressure is 0.7Mpa and 1.0Mpa, and the tire contact width is 18.6cm. The tire contact length L can be calculated as 21.1cm using the formula, and δ = 1.1;

[0102] When defining the creep analysis step, set the creep analysis step duration to the load cumulative action time. The calculation formula for the load cumulative action time is as follows:

[0103] For normal driving sections, the calculation expression for the cumulative load action time is as follows:

[0104]

[0105] For road intersections, the calculation expression for the cumulative load action time is as follows:

[0106]

[0107] Where a is the absolute value of acceleration during braking.

[0108] Where, the tire contact width is 18.6 cm, the vehicle axle weight is 100 kN, the number of wheels on the axle is 4, the tire contact pressure is 0.7 MPa, δ = 1.1, and the acceleration during braking is 3 m / s 2The total duration of action was 971 seconds. According to past traffic statistics, road surface temperatures typically exceed 50°C between 12:00 and 18:00, with an average traffic volume percentage of 7.5%. During high-temperature periods, the number of traffic volumes affected per hour was approximately 234, with a cumulative action time of 74 seconds.

[0109] Applying a vehicle vertical load to the asphalt road 3D model; specifically, in this embodiment, the vertical load values ​​are 0.7 MPa, 1.0 MPa, and 1.4 MPa; Applying boundary conditions to the asphalt road 3D model; specifically, in this embodiment, the asphalt road 3D model is constrained in the normal direction on all sides, and in the X, Y, and Z directions on the bottom;

[0110] S50. Grid the asphalt road three-dimensional model and perform calculation and analysis to finally obtain the vertical and lateral displacement values ​​of the asphalt road in the creeping heavy-load traffic section:

[0111] Effect of temperature on asphalt pavement structure (0.7Mpa, 3m / s 2 ):

[0112] Road surface temperature 50℃ 55℃ 60℃ 65℃ 70℃ Maximum vertical displacement (mm) 3.65 6.27 8.13 9.24 11.87

[0113] Effect of heavy load on asphalt pavement structure at high temperature (70℃, 3m / s 2 ):

[0114] load 0.7Mpa 0.9Mpa 1.0Mpa 1.2Mpa 1.4Mpa Maximum displacement (mm) 11.87 13.45 14.17 15.49 16.68

[0115] Impact of low speed on asphalt pavement structure at high temperature (70℃, 0.7Mpa):

[0116] speed 1km / h 3km / h 5km / h 7km / h 9km / h Maximum displacement (mm) 15.26 9.75 7.86 6.81 5.82

[0117] The Chinese standard (JTG H10-2009) stipulates that minor repairs are required when the rutting depth is ≥10mm. In sections with creeping heavy traffic, high temperatures are more likely to cause rutting. The rutting displacement generated in one hour at a high temperature of 70°C is 1.46 times that generated at 60°C. In the context of global warming, the rutting generated in extreme high temperature weather is greater than the sum of the rutting displacement at other times of the year, so the experimental temperature was selected as 70°C. Under heavy loads and forward axle load displacement during braking, the vertical displacement generated by a ground pressure of 1.4 MPa at a high temperature of 70°C is 1.4 times that of a ground pressure of 0.7 MPa. Compared with 1.4 MPa and 0.7 MPa, a ground pressure of 1.0 MPa is more common, so the experimental bar is set to 1.0 MPa. At low speeds, the vertical displacement generated at a speed of 1 km / h is 2.6 times that generated at a speed of 9 km / h. Near road intersections, creeping low-speed driving is more common, so the round-trip rolling speed is set to 30 times / min±1 time / m (15 round-trip times / min).

[0118] S60. By analyzing the effects of high temperature, heavy load and low speed on asphalt roads, a method for evaluating asphalt pavement rutting in creeping heavy load traffic sections is proposed.

[0119] On creeping, heavily loaded traffic sections, due to high temperatures, low speeds, and overloads, existing evaluation methods are no longer able to meet the rutting resistance requirements of asphalt mixtures under these special conditions. Based on the analysis of numerical simulation results, a new asphalt mixture evaluation method, the dynamic stability test, is proposed. The specific content is as follows:

[0120] Experimental Preparation and Conditions: The specimen table can securely mount a test mold for a specimen of the specified size, 300mm wide. The test wheel is a steel wheel with an outer diameter of 200mm and a wheel width of 50mm. The test wheel travel distance is 230mm±10mm, and the reciprocating rolling speed is 30 times / min±1 time / m (15 times back and forth / min). The loading device can ensure that the contact pressure between the test wheel and the specimen is 1.0MPa±0.05MPa at 70°C. The rutting tester must be installed in a constant temperature chamber equipped with a heater, air circulation device, and automatic temperature control equipment to maintain a room temperature of 70°C±1°C, a specimen internal temperature of 70°C±0.5°C, or other required temperatures.

[0121] Dynamic stability requirements:

[0122]

[0123] Therefore, the purpose of the present invention is to provide a method for evaluating the vertical rutting of asphalt pavement in creeping heavy-load traffic sections, so as to solve the problem that rutting is easily generated in creeping heavy-load traffic sections, and to provide certain guidance for the optimization design of asphalt mixture ratio and economic rationality design of asphalt pavement.

[0124] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the same. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solutions of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for evaluating rutting on asphalt pavement in creeping heavy-load traffic sections, characterized in that: The following steps are involved: S10. Conduct a traffic volume survey on the creeping heavy-load traffic section to obtain the total traffic volume for the entire day and the traffic volume ratio per hour, and convert the actual traffic load into the number of standard axle load actions; S20. Determine the structural dimensions and layer thickness of the asphalt pavement required for simulation based on the asphalt pavement structure; obtain asphalt pavement material parameters by consulting specifications and literature; establish a three-dimensional asphalt pavement model based on the structural dimensions of the asphalt pavement and assign material properties; define the material behavior of the asphalt pavement material as creep; S30, inputting asphalt road material parameters into the asphalt road three-dimensional model; Calculate the temperature field of the asphalt pavement structure at high temperature and import the calculated temperature field into the asphalt road 3D model; S40, determining the contact area between the tire and the asphalt pavement during road braking, and determining the creep analysis step length based on the number of standard axle load applications; applying a vertical vehicle load to the asphalt road three-dimensional model, and applying boundary conditions to the asphalt road three-dimensional model; S50, meshing the asphalt road three-dimensional model and performing calculation and analysis to ultimately obtain the vertical rutting displacement value of the asphalt road in the creeping heavy-load traffic section; S60. By analyzing the effects of high temperature, heavy load and low speed on asphalt roads, a method for evaluating asphalt pavement rutting in creeping heavy load traffic sections is proposed.

2. The method for evaluating rutting on asphalt pavement in creeping heavy-load traffic sections according to claim 1, characterized in that: The expression for converting actual traffic load into the number of standard axle load actions in S10 is as follows: Where N 等效 Indicates the number of times the standard axle load acts, P i represents the actual axle weight of the i-th type axle, P 标准 Indicates the standard axle load specified in the specification, N i It represents the number of times the i-th type axis is acted upon, and n represents the damage index.

3. The method for evaluating rutting on asphalt pavement in a creeping heavy-load traffic section according to claim 2, characterized in that: Asphalt road material parameters include heat flux density q, thermal conductivity k, rebound modulus E, temperature T, Poisson's ratio μ, and creep material parameters. Creep material parameters include power multiplication law A, equivalent stress order n, and time order m. The established three-dimensional asphalt road model includes: creating components, selecting the model space as three-dimensional, selecting the model type as deformable, selecting the shape as solid, and finally assigning the model material parameters.

4. The method for evaluating rutting on asphalt pavement in creeping heavy-load traffic sections according to claim 3 is characterized by: In S30, the material behavior of the asphalt road material is defined as creep, wherein the creep deformation ε of the asphalt road is cr It is a function of temperature T, stress q and time t, and the expression is as follows: ε cr =f(T,q,t); If the stress q is kept constant during analysis, the expression of the time hardening creep model is: in, is the uniaxial equivalent creep strain rate, the power multiplication law A, the equivalent stress order n, and the time order m are model parameters; Calculate the temperature field of the asphalt pavement structure at high temperature and import the calculated temperature field into the asphalt road 3D model; For multilayer materials, the temperature field distribution of each layer can be quickly obtained according to Fourier's law of heat conduction: T surfrace is the road surface temperature; h i is the thickness of the i-th layer; k i is the thermal conductivity of the i-th layer; q is the heat flux density.

5. The method for evaluating rutting on asphalt pavement in creeping heavy-load traffic sections according to claim 4 is characterized by: The process of determining the contact area between the tire and the asphalt road surface during road braking in S40 and determining the creep analysis step length according to the number of standard axle load applications is as follows: Calculate the contact area A between the tire and the asphalt road surface during road braking using the following expression: A=LB; Where B is the tire contact width in cm, L is the tire contact length in cm, δ is the axle load distribution coefficient, P is the vehicle axle weight in kN, n w is the number of wheels on the axle, in pieces, and p is the tire ground pressure, in MPa; The creep analysis step length is determined based on the number of standard axle load actions. The creep analysis step length is set to the cumulative load action time. For normal driving sections, the calculation expression for the cumulative load action time is as follows: Where, t is the cumulative action time of wheel load, in seconds; v is the initial speed at braking, in km / h; B is the tire contact width, in cm; P is the vehicle axle weight, in kN; n w is the number of wheels on the axle, in units of pieces; N is the number of times the wheel load acts, in units of times; p is the tire ground pressure, in units of MPa; Considering the braking situation, the calculation expression of the cumulative load action time is as follows: Where a is the absolute value of acceleration during braking; t is the cumulative action time of wheel load, in seconds; B is the tire contact width, in cm; P is the vehicle axle weight, in kN; n w is the number of wheels on the axle, in units of pieces; N is the number of times the wheel load acts, in units of times; p is the tire ground pressure, in units of MPa; δ is the axle load distribution coefficient.

6. The method for evaluating rutting on asphalt pavement in creeping heavy-load traffic sections according to claim 5, characterized in that: In S40 , the boundary conditions imposed on the asphalt road three-dimensional model are specifically: normal constraints are applied to the four sides of the asphalt road three-dimensional model, and X, Y, and Z constraints are applied to the bottom.

7. The method for evaluating rutting on asphalt pavement in creeping heavy-load traffic sections according to claim 6, characterized in that: According to the results calculated in claim 5, the effects of high temperature, heavy load and low speed on asphalt roads are analyzed. Based on the analysis and calculation results, new dynamic stability experimental conditions are proposed, including experimental temperature, wheel load size, and number of round-trip rolling times. Finally, a rutting evaluation method for asphalt pavement in creeping heavy-load traffic sections based on the new experimental conditions is proposed.

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