Abstract:

The ultimate bearing capacity of foundation based on Mohr-Coulomb strength criterion does not consider the influence of intermediate principal stress on yield and failure of soil. In this paper, the influence of mean principal stress on the ultimate bearing capacity of foundation was taken into account based on twin shear strength theory. Formulae were derived with the influence of soils cohesive strength, over-burden loads on both sides of foundation and the self weight of soils. Taking strip foundation as an example, the influence of intermediate principal stress on the ultimate bearing capacity of foundation was calculated. The ultimate bearing capacity of foundation will be improved, when the influence of intermediate principal stress on the bearing capacity of foundation is considered.

Key words: ultimate bearing capacity of foundation, intermediate principal stress, twin shear strength theory