The failures of the reinforced geosynthetic sand can be divided into three types, i.e. the fracture inducedfailure, the friction inducedfailure, and the over deformation inducedfailure. It is considered that different strength theories should be adopted for simulation of different types of failures. Based on the concept of frictioninduced equivalent additional stress and the MohrCoulomb Theory, an analysis is made of triaxial reinforced samples, and their failure types and corresponding formulas for st...