Research on dynamic strain distribution patterns of asphalt pavement under the influence of hydro-thermo-mechanical interactions

Strain is a crucial indicator of the design of the asphalt pavement. To qualitatively and quantitatively study the distribution laws of dynamic strains under the coupling of multiple factors, this paper constructs single stress, hydro-mechanical, thermo-mechanical and hydro-thermo-mechanical models, which study the state and numerical value differences of dynamic strains in various physical fields, and explores the distribution characteristics of dynamic strain components within the pavement zone under coupling of hydro, thermal, and mechanical processes. The results show that under different physical fields, the absolute values of the peak dynamic strains (lateral, longitudinal and vertical) at the wheel load center decrease as pavement depth increases, but the numerical values and waveform change laws of dynamic strains in different directions are different. The peak absolute value of the ayy is the highest, followed by the axx, and the azz is the smallest. Among the three shear strain components, ayz has the largest peak absolute value, followed by axy, and axz has the smallest peak absolute value. The numerical differences of the a1 peak in various physical fields are large, and the dominant factors of negative and positive peak are different. At Y= 0 m, the negative peak of the a1 under hydro-thermo-mechanical coupling is 2.4 times that under the action of hydro-mechanical field. The negative peak of the a1 under the action of thermo-mechanical field is 2.5 times that under single stress field. Along the road horizontally and longitudinally, the axx and ayy both show alternating positive and negative changes, suggesting that the road material alternates between compression and tension, which is easy to cause cracks. With the increase in pavement depth, the superposition phenomenon of the dynamic strain peak values is more obvious, and the extent of dynamic strain action in the lateral and longitudinal directions of the pavement is widening. The research results have certain reference value for the design of long-life asphalt pavement.