Based on the whole slope stress field obtained from block element and the joint stress field calculated by distinct element method

combining with the definition of vector sum method (VSM)

a new slope stability analysis method is proposed

namely VSM-universal distinct element code (VSM-UDEC) method. Firstly

the accuracy of contact stress and element stress calculated by UDEC under various conditions is verified by the slider test. It is shown that the contact stress and element stress fields have high precision (i.e.

the relative error of contact stress is less than 0.2%)

which satisfies the condition of safety factor calculation. Numerical simulations of a linear sliding surface and a circular sliding surface are analyzed by the VSM-UDEC method. Numerical results are compared with the solutions by the corresponding theory and the rigorous limit equilibrium method (Morgenstern-Price method). It is indicated that the safety factor obtained by the VSM-UDEC method is almost identical with that by the theoretical solution in the case of linear sliding surface

and is consistent with that by the limit equilibrium method in the case of circular sliding surface. Finally

the VSM-UDEC method is applied to analyze the stability of the left bank slope of the Jinping-I Hydropower Station. The results demonstrate that the safety factor by the VSM-UDEC method is good agreement with that by the limit equilibrium methods (Sarma method

Morgenstern-Price method) when blocks are regarded as rigid. Moreover

the VSM-UDEC method can be considered as the effect of the structural surface in the slope body on the slope stability

and thus it has more advantages than the limit equilibrium method to reflect the actual stability and deformation distribution situation of the slope. UDEC software has good applications of simulating slope failure process and VSM has the clear physical significance of safety factor

and therefore

the VSM-UDEC method may have good prospects of applications in the slope stability analysis.