Abstract: The waste soil disposal area in a mountainous highway construction has the characteristics of complex disposal material sources and large compactive effort differences, and its geotechnical mechanical parameters are random, which leads to a greater uncertainty in the slope stability in the waste soil disposal area. The study on the reliability of the slope stability of the waste soil disposal area has a strong engineering practical significance for the reasonable evaluation of the stability of the waste soil disposal area. The Monte-Carlo method is used to establish the reliability analysis model of the slope stability of the waste soil disposal area, and the stability and reliability at the 140m soil disposal area on the right side of K89+250 of Liupanshui-Weining Expressway in Guizhou Province are studied. The results show that the geotechnical mechanical parameters of the soil disposal area have obvious distribution characteristics, the slope stability coefficient of the residues disposal area is greater than he allowable safety coefficient, and the failure probability of the slope in an unstable state is 15.8%, which is a low-risk state. Therefore, the slope of the waste soil disposal area meets the requirements of stability and safety. The calculated safety factor and instability probability analysis of the slope stability of the soil disposal area can reflect the stability of the waste soil disposal area, which can provide a guarantee for the long-term safe operation of the soil disposal site.

Key words: Waste Soil Disposal Area, Slope Stability, Monte Carlo Method, Reliability Analysis