Abstract: The search for non-circular slip surface is a key to slope stability analysis, and its essence is to find a slide path with a minimum safety factor. Using radial movement optimization, a new global optimization algorithm, to search a path has advantages in calculation, storage and step, but the result is unstable. To overcome the instability of the algorithm in the searching process, its data structure is adjusted and an improved radial movement algorithm is developed, which make the route search stable. A safety factor corresponding to a searched path is calculated with unbalanced thrust method. Under the premise of feasibility analysis, the dichotomy is employed to solve the safety factor quickly and accurately. Based on a calculation example of a reservoir bank slope, the effectiveness of the improved radial movement algorithm is verified. Analyzing and comparing the search results obtained by improved radial movement optimization algorithm and particle swarm optimization, it is shown that the former is apparently superior to the latter in convergence and stability.

Key words: slope, non-circular critical slip surface, radial movement optimization(RMO), unbalanced thrust method, dichotomy