Dynamic Response of a Low Embankment Subjected to Traffic Loads on the Yangtze River Floodplain, China

Roadways with low embankments may undergo considerable postconstruction settlement under traffic loads, which can significantly threaten roadway safety. This study aimed to investigate the dynamic response of a low embankment subjected to moving traffic loads on Yangtze River floodplain soils. Dynamic earth stress sensors were installed to monitor the dynamic responses at different depths. Heavy and light vehicles were allowed to drive over these at speeds ranging from 20 to 80 km/h. To verify the effect of pavement thickness, field tests were conducted at two different stages in roadway construction. The spatial distributions and transfer mechanisms of dynamic stress under moving traffic loads were examined through measured data. In addition, a three-dimensional finite-element model was established to further analyze the vertical acceleration and displacement caused by dynamic traffic loading. The results indicated that, with the completion of a semirigid subbase, the significant-influence depth was about 1.6 m under the heavy-vehicle load. In contrast, the dynamic stress became negligible in the upper subgrade layers after completion of the pavement structure, indicating the dominant role of the pavement structure in dispersing dynamic stress. The dynamic responses intensified with increasing magnitude of vehicle load and vehicle speed, but the effect reduced with decreasing pavement roughness. Furthermore, the significant-influence depth of vertical displacement was markedly greater than that determined by dynamic stress.