Thermal failure for saturated clay under undrained condition

A large deformation would be produced and failure occurs for saturated clay under undrained heating condition at a constant total nonisotropic stress state revealed by test data. Heating should be thought as another loading way. Firstly, an expression of undrained shear strength considering thermal effect is obtained based on the thermal unified hardening (UH) critical state model proposed by Yao et al. Comparison between simulation and test data about undrained shear strength under heating condition for overconsolidated clay with different over consolidation ratios(OCRs) has shown that the variation regularity of undrained shear strength considering thermal effect can be described using the proposed formula. The process at a constant total nonisotropic stress state with heating under undrained condition is simulated using thermal UH model. The prediction result has shown that the thermal UH model can be applied to describe stress-strain relationship and variation regularity of shear strength under undrained condition for saturated clay reasonably. Finally, the value of deviatoric stress ratio at initial time for heating, the magnitude of heating, OCR and preconsolidation pressure are all discussed and analyzed. The regularities of stress-strain relationship and property of strength for saturated clay under undrained condition affected by above factors are obtained.