Research On Cracking Mechanism Of Semi-Rigid Asphalt Pavement Based On XFEM

As a typical pavement structure,semi-rigid base asphalt pavement is widely used in the construction of high-grade highways in our country.Due to the emphasis on the strength of the water-stabilized base in the early construction process,and the improper maintenance and management measures during the construction process,lateral cracking is common in the early semi-rigid base.Under the action of vehicle load and temperature and humidity changes,the gradual expansion of pavement cracks accelerates the damage process of the pavement structure,which eventually leads to the decline of the pavement structure’s service performance and shortened service life.Aiming at the actual situation of cracking and failure of semi-rigid asphalt pavement structure,based on the extended finite element theory,using the ABAQUS finite element calculation and analysis platform,the crack propagation characteristics of semi-rigid asphalt pavement under the coupling action of dynamic and static vehicles and temperature loads are systematically analyzed,and the effect of some engineering measures to suppress reflection cracks is discussed.The main research contents of the paper are as follows:(1)In order to study the crack propagation of reflection cracks in semi-rigid asphalt pavement structures under vehicle loads,a finite element calculation model of semi-rigid asphalt pavement structures with cracks is established based on the extended finite element method.The effects of crack angle,crack length,load parameters and structural parameters on the propagation behavior of reflective cracks are mainly analyzed.At the same time,the fatigue life of reflective cracks under eccentric loading cycles is calculated using the damage evolution equation based on fracture energy.(2)Aiming at the temperature changes in winter and summer in Henan,a structural analysis model of asphalt pavement with lateral reflection cracks is established considering the external airflow,solar radiation and atmospheric temperature changes,and the distribution law of the temperature field of typical asphalt pavements in summer and winter is obtained respectively.On this basis,the effect of temperature change on the propagation of reflective cracking in semi-rigid asphalt pavement is studied,and the cracking failure law of reflective cracking in semi-rigid asphalt pavement under the coupling action of vehicle load and temperature in typical winter time is analyzed.The propagation mechanism and main influencing factors of reflective cracks in semi-rigid asphalt pavement under the combined action of vehicle load and temperature change are revealed.(3)Referring to the typical cracking mode of semi-rigid asphalt pavement structure,a finite element calculation model of semi-rigid base asphalt pavement containing both Top-Down cracks and base reflection cracks is established.The interaction between crack spacing and Top-Down crack depth on crack propagation under moving loads is analyzed.The corresponding calculation and analysis of typical reflective crack prevention measures are carried out,which provides a certain technical basis for rationally evaluating the engineering design for restraining reflective crack cracking.