Accumulative Deformation Characteristics of Saturated Soft Clay Under Subway Loading in Shanghai

Abstract:

Through the dynamic triaxial tests for the saturated silt soil around the tunnel of the Jing’an Temple Station,the deformation analysis is made on the saturated soft clay under the subway train loading.The results show accumulative plastic strain increases with larger amplitude of dynamic stress and less loading frequency with the same vibration times.Orthogonal design is used to arrange the experiment by taking a full consideration of the factors which have effect on the accumulative deformation,such as vibration times,the loading frequency,the amplitude of dynamic stress,and the interaction between one factor and the other.The mathematical statistics approach is established and is used to analyze the influence rate of the deformation.It also shows that main factor which affects axial deformation of subway tunnel is the dynamic stress amplitude and the interaction function on vibration frequency and vibration times can be ignored.The study offers a valuable reference to the design of subway tunnel.

Key words:subway loading; deformation characteristics; soil dynamic test; saturated soft clay