| At present the current road design theories and performance evaluation methods in our country mostly take the pavement structure under static load as the research object.However,the effect of the driving vehicle on the pavement is usually a dynamic load whose size and position are constantly changing over time,which causes the current highway design theory and performance evaluation method to not be fully applicable to the performance evaluation of asphalt pavement in my country.With the widespread use of Falling Weight Deflectometer(FWD),how to establish the dynamic response model of asphalt pavement under FWD impact load,and the inversion of pavement structure layer modulus based on FWD deflection basin data has become a reality at home and abroad.Research hotspots of asphalt pavement performance evaluation.At the same time,as the seasonal climate changes,the internal temperature of the pavement structure will change significantly.For the temperature-sensitive asphalt mixture,the temperature change will affect its mechanical properties,and then affect the bearing capacity and stability of the pavement structure.In view of the above situation,this paper has carried out the research on the dynamic response and back analysis of the semi-rigid base asphalt pavement considering the influence of temperature.The research results have theoretical guiding significance for the dynamic design and performance evaluation of pavement structure.The main work of this paper is as follows:(1)Based on the basic theory of spectrum element method,the dynamic response of semi-rigid base asphalt pavement structure is analyzed,and the dynamic response calculation program of semi-rigid base pavement is compiled.The calculation results are compared with the ABAQUS numerical analysis and the measured deflection results.The results show that the calculation results in this paper have higher accuracy,and compared with the finite element method,the calculation efficiency of the spectral element method has been effectively improved.On this basis,the influence law of semi-rigid base pavement structure modulus and thickness on pavement deflection was systematically studied.(2)Considering that under the influence of temperature,the material modulus of the asphalt surface course has a heterogeneous gradient characteristic,the spectral element method is used to establish the mechanical model of the change of the lower layer modulus with the temperature gradient under the FWD load,and the seasonal variation of the road surface deflection is analyzed.And the diurnal variation rules,and compared with the deflection calculation results of the traditional isothermal model.On this basis,a temperature correction formula suitable for semi-rigid base pavement deflection is established.(3)Based on the improved sparrow search algorithm(ISSA),the least squares support vector machine model(LSSVM)parameters and the selection of pavement modulus are optimized,and the dynamic inversion method of pavement structure layer modulus based on ISSA-LSSVM is proposed,and the pavement model is compiled.Quantitative dynamic inversion procedure.The calculation results of calculation examples and engineering examples prove that the inversion method in this paper has higher accuracy,and compared with the original sparrow search algorithm,the inversion accuracy of the improved sparrow search algorithm has been improved.On this basis,the sensitivity analysis of the inversion modulus of the pavement structure layer was carried out,and the influence of temperature on the inversion modulus of the surface layer was considered,and a temperature correction method for the inversion modulus of the surface layer based on the temperature correction coefficient of the surface layer modulus was proposed method. |
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