Spatial distribution of vibration accelerations in coupled rail-embankment-foundation system on high-speed railway under moving loads

To obtain the spatial distribution of accelerations induced by moving loads, a coupled nonlinearly true three-dimensional numerical model for high-speed railways with a design speed of 350 km/h is established based on the multi-scale and precisely modeling technology. The model is composed of rails, fasteners, cement-asphalt (CA) mortar, reinforced concrete roadbed, upper layer of roadbed, lower layer of roadbed, embankment and foundation. The dynamic interaction between bottom of the reinforced concrete base and surface of the upper layer of roadbed is simulated using the dynamic contact algorithm. The radiation damping and elastic recovery of infinite foundation are simulated using the three-dimensional viscoelastic static-dynamic unified artificial boundary. Considering the objective influence of static stress state in the embankment before action of the moving loads on the subsequent dynamic computation and the nonlinearities of foundation soils and backfilling materials of the embankment, generation of the initial stress state of the foundation, construction of the embankment and rail system and subsequent operation of electric multiple unit (EMU) train with 8 cars are simulated using the large-scale parallel computation. The distribution of accelerations in time and space-domain for different components of rail-embankment-foundation system is summarized based on the analysis results. The advantages using solid elements to simulate spatial dynamic behaviors of rails are validated.