Analysis Of Dynamic Response And Plastic Deformation Of Urban Asphalt Road Subgrade Under Vehicle Load

The subgrade is the support of the pavement structure. Speaking of the urban road, the height of the earth fill is limited and many of them have no embankments .The pavements damage such as settlement, rutting and crack which appear in the using process, partly because of the pavements structure deformation by themselves, but quite majority are induced by excessive plastic deformation of the subgrade soils. The subgrade deformation mainly come from soil self-weight compaction, soil consolidation and accumulative plastic deformation under vehicle load. This thesis presents a research on dynamic response and plastic deformation of the subgrade soils under vehicle load.Four parts are included in this thesis as follows:At present , "Specifications of asphalt concrete pavement" JTJ014-97 has stipulated that each contact surface condition of the pavement structure are completely continuous .In fact ,some contact surface conditions among the pavement structure are partial continuous or even glide. In the first part, static analysis of the pavement structure is discussed by elastic layered system theory with the forepart damage phenomena of the pavement explained above.In the second part ,the numerical model of urban road in our country is built and dynamic response of the subgrade soils influenced by moving dynamic vehicle load is studied by three-dimensional, dynamical finite element program. It has been studied in three different views such as the vehicle overload rate, vehicle speed and the number of axle which influence the result of subgrade soils dynamic response separately.Using an empirical cumulative plastic strain formula ,in the third part ,a method for calculating cumulative plastic deformation of the subgrade soils induced by vehicle load was proposed combined by the stress result gained in the second part. At the end of this part, taking the 501RF part of caltrans accelerated pavement test (cal/apt) program in California for example ,the validity of the method is confirmed. Finally, the residual deformation of soft clay subgrade in Shang Hai under...