Analytical Solutions of Critical Load and Terzaghi’s Ultimate Bearing Capacity for Unsaturated Soil

Abstract:

Based on the unified solution of shear strength for unsaturated soil in terms of two state stress variables,analytical solutions of the critical load and Terzaghi’s ultimate bearing capacity for unsaturated soil strip foundation are obtained by taking into consideration the influences of intermediate principal stress,matric suction and overconsolidation ratio.The influence laws of the unified strength theory parameter,matric suction and overconsolidation ratio on the analytical solutions are discussed.The results show that the analytical solutions obtained in this paper have a good comparability to many existing results; the formula of critical load can be suitable for any lateral pressure coefficient; the critical load and Terzaghi’s ultimate bearing capacity increase significantly with the increasing of the unified strength theory parameter and matric suction; there is a linear increase relationship between the critical load and overconsolidation ratio,and the critical loads corresponding to different matric suction are parallel to each other.

Key words:unsaturated soil; unified strength theory; critical load; ultimate bearing capacity