Dynamic Response and Deformation Behavior of Soft Clay Under High-Speed Railway Loads

Railway construction is concentrated in the Chinese southeast coastal area, where thick soft clay is widely distributed. Under dynamic loading, the deformation and dynamic modulus of weak soft soil can change significantly. To discuss the effect of high-speed railway loads on soft clay, a series of dynamic tri-axial tests were designed and conducted to study the dynamic response and cumulative deformation of soft clay under different loading stress amplitudes and frequencies, based on the analytical solution of additional stress of railway subgrade. The results show that loading frequency has limited influence on dynamic elastic modulus under low cyclic stress. The degradation of dynamic modulus increases when the cyclic stress ratio is larger than 0.125. Meanwhile, the softening index has good linear relationship with dynamic strain. By combining the softening index with cumulative plastic deformation, the dynamic and static characteristics of soft clay can be consistently discussed. It is found that they have good correlation.