Abstract:

Based on the vector characteristics of forces, the vector expression of the safety factor in the vector sum analysis method (VSAM) is presented. In a slope with certain conditions, after determining the stress distribution with FEM, the critical slip surface can be searched with VSAM and the direct method in optimization algorithm. The calculated results show that the locations of the critical slip surfaces are in good agreement with the ones with Morgenstern—Price (M-P) limit equilibrium method, and the maximum relative error is only 2.09 percents between the safety factor obtained by VSAM and that by M-P method in calculated examples, which proves that VSAM is reasonable and reliable. At present, the methods with the safety factor of strength reserve are widely used in slope engineering; however, VSAM is different from the methods above。VSAM is clear in physics; the formula and its calculating process are very simple; and it will be easy to be applied in 3-D slope stability analysis. So VSAM can be widely used in practice.

Key words: vector sum analysis method, slip surface search, limit equilibrium method, slope stability analysis