Abstract: Connected with the engineering concrete example, through the collection, arrangement and analysis of related data, the site investigation and exploration of engineering geology, indoor and outdoor physico-mechanical tests, adopting the analytic means of mathematic statistics, unbalanced-thrust method and non-separation contact elastoplastic FEM together, the influencing factor sensitivity of debris landslide has been analyzed and researched. The results show as follows. First, through the sensitivity analysis of main factors to influence on the stability of debris landslide, its main influenced factors are internal friction angle of sliding surface, topographic grade, saturation-area ratio of slope-mass and cohesion of sliding surface by descending order of their sensitivity coefficients. Second, the integral stability coefficient of debris landslide with large topographic grade and the slip surface of small internal friction angle is more inferior. But steady rain and intensive rainfall can raise groundwater level, augment saturation-area ratio of slope-mass, lower the rock and soil shear strength of slip-surface, and increase downward sliding force, which will bring about the most disadvantage influence on the stability of a concrete debris landslide. Meanwhile, on reinforcing and treating the debris landslide, the measure raising equivalent angle of slip-surface internal friction and lowering topographic grade connected with lowering groundwater level must be taken the prior step, and may be thought over taking the next measure to increase the soil and rock cohesion of slip surface.

Key words: debris landslide, elastoplastic FEM, contact algorithm, unbalanced-thrust method, sensitivity of influencing factors