Abstract: For most of the existing algorithms for calculating ultimate bearing capacity of jointed rock masses based on Hoek-Brown strength theory, they have not considered the effect of intermediate principal stress; so these algorithms cannot make full use of rock strength. Combining the advantage of nonlinear unified strength criterion and Hoek-Brown nonlinear failure criterion, and taking the impacts of earthquake loads into account, a new algorithm for computing the bearing capacity of foundation based on critical sliding field theory is proposed. The experiment results demonstrate that the bearing capacity of the foundation is enhanced based on nonlinear unified strength theory; the existing methods of bearing capacity of foundation are relatively conservative, so the bearing capacity of foundation will reduce under the effects of earthquake loads.

Key words: rock mass mechanics, foundation bearing capacity, nonlinear unified strength criterion, Hoek-Brown nonlinear failure criterion, critical slip fields, earthquake loads