Analysis Of Failure Modes And Mechanism Of Subgrade Under Earthquakes And Recommendations For Improving Seismic Design

To study the seismic failure effect of subgrade, the field investigation and analysis of seismic failure of the subgrade are conducted. six seismic failure modes of the subgrade are proposed, (1) shallow surface sliding of slope, (2) development of slip surface within the body of subgrade, (3) development of slip surface reaching the foundation, (4) overall sliding of sloping subgrade, (5) slumping, and (6) desification. Meanwhile, the investigation shows that seismic subsidence rate and wave-like deformation amplitude rise with the increase of seismic intensity, the degree of subgrade damage is closely related to the characteristics of route selection. The research has analyzed the seismic damage mechanism of the subgrade, explores a new concept of seismic design based on allowable deformation proposed by Ikuo Towhata.