Investigation And Modeling Of Pore Pressure For The Saturated Asphalt Mixture Under Dynamic Load

Asphalt concrete pavement is widely used for its superior comfort performance.A large-scale construction of the pavement will bring about a large area of subsequent repair of the asphalt pavement The water damage of the asphalt pavement is one of the main diseases of the pavement.In the rainy season,when the asphalt pavement has experienced dozens of days of vehicle load,the pavement will appear loose,cracked,etc.,and gradually form cracks.Due to the presence of water,the excess pore water pressure generated by the coupling of the waterway of the vehicle has a certain influence on the asphalt pavement.At present,there is controversy about the definition of excess pore water pressure.(The excess pore water pressure studied in this paper is the pore water pressure beyond the steady flow,that is,the hydrodynamic pressure in the existing research.)Among them,the damage of excess pore water pressure is the largest and the most obvious.Studying the water damage problem of asphalt pavement has always been a hot issue in the field of road engineering and it is very important to improve the road performance of asphalt pavement.The problem of excess pore water pressure is the core content of water damage.The research in the field of soil mechanics is relatively mature,and the study of excess pore water pressure in asphalt mixture is rare.Among the existing research results,a large number of numerical simulations and field measured data show that the excess pore water pressure in the saturated asphalt mixture is related to various factors such as the magnitude of the applied load,the ambient temperature and the loading frequency,and specifically reflects the excess pore water.The quantitative relationship between stress and its influencing factors and the associated experimental data have few results.In addition,the model for the development of excess pore water pressure has been developed very mature in soil mechanics,and the model of excess pore water pressure in asphalt mixture is rare,its parameter calibration and parameter value law.The problem is not well solved.Therefore,it is very important to study the development law and model of excess pore water pressure in saturated asphalt mixture under dynamic load.These work have been paid much attention by road workers at home and abroad.In this paper,the classical effective stress principle and triaxial test principle of soil mechanics are combined with laboratory tests to systematically study the internal excess pore water pressure of the saturated asphalt mixture under dynamic loading.Firstly,the calculation model of excess pore water pressure considering void fraction parameters is proposed,and its rationality,applicability and development law are analyzed.Secondly,the dynamic triaxial test of indoor saturated asphalt mixture was carried out,and the development law of excess pore water pressure under certain factors such as stress level,loading frequency,ambient temperature,void ratio and confining pressure was obtained,and the impact of different factors on excess pore water pressure were analyzed.The relationship between the excess pore water pressure and the deformation law during the asphalt mixture test and the failure state of the saturated asphalt mixture were obtained.Finally,using the data obtained from the indoor dynamic triaxial test,the parameters of the excess pore water pressure theoretical calculation model are calibrated under different void ratio conditions,and the calculation model of the excess pore water pressure with the most theoretical and practical value is finally determined.The research results obtained in this paper clarify the development law of excess pore water pressure,which helps people to further understand the mechanism of water damage,and provide ideas for effectively solving the problem of water damage on asphalt pavement in the actual construction of asphalt pavement in the future.It has important theoretical significance and practical value for improving the fatigue life of asphalt pavement and the durability and road performance of pavement and reducing economic loss.