Abstract: In order to overcome the shortcomings by using the traditional finite element method, this paper presents a new method in the stability analysis of soil-rock slopes considering the random distribution and proportion of rock blocks. Based on the rock block proportion and gradation of soil-rock slope, the soil-rock mixture model is randomly generated for the rock block proportion in the range of 10% to 60%. Each rock block proportion model takes into account eight different block distribution locations. Finally, the generated model is imported into OPTUM G2 to establish the model of soil-rock slopes. The stability of soil-rock slopes is analyzed by finite element limit analysis method, and the calculated results are compared with those obtained by two kinds of equivalent strength parameter models. The results show that the maximum and minimum limits of safety factors of soil-rock slopes with the same rock block proportion vary greatly due to the difference in the spatial distribution of blocks. The plastic zone in the soil-rock slopes is no longer circular-shape, but shows three typical expansion modes of "around stones", "distributary" and "inclusion". The safety factors of soil-rock slopes obtained by using two kinds of equivalent strength parameter model and random rock block model are quite different. The research results can provide reference for the design and construction of soil-rock slopes.

Key words: random block stone model, soil-rock slope, stability, limit analysis, rock block proportion