The jointed rock mass possesses complex mechanical behaviors

the ultimate bearing capacity of foundations of jointed rock masses has not been studied in detail from a theoretical point of view. An analytic expression has been developed that enables the shear strength to be determined using the nonlinear strength criterion which takes influence of intermediate principal stress on the yield and failure of jointed rock masses into account. The important concept of instantaneous friction angle is defined. This paper defines a methodology for load bearing capacity quantification based on the nonlinear unified strength criterion and by applying the characteristics method for resolving the differential equation systems which govern the stress field. The boundary conditions are defined by the external load system and the geometrical configuration are incorporated. The closed form solution is obtained. To facilitate an overall understanding of the procedure

an example problem is solved showing how the initial data are used . Results show that the properties of jointed rock masses and intermediate principal stress importantly affect the ultimate load bearing capacity of foundation.