Experimental Study on Cumulative Deformation of Silty Sand Roadbed under Repeated Loading

In order to effectively forecast the non-uniform cumulative settlement of silty sand roadbed under long term repeated traffic loading,it is important to reflect deformation patterns of silt sand reasonably under different stress levels and initial status.By adopting GDS triaxial apparatus,a series of cyclic loading tests were performed with consideration of different initial densities,different initial confining pressures and different cyclic stress levels.Test result shows that(1)the increment rate of plastic strain is lager with the higher dynamic stress level,the smaller density and the lower confining pressure;(2) the increment ratio of plastic strain reduces gradually with the increment of load cycles;(3)the relationship between cumulative deformation and load cycles accords with power law.Thereby,a new forecasting cumulative equation and calculating approach were proposed to reflect the effects of different influencing factors.