Research On Slope Reliability Based On The Strength Reduction Method

There are many dangerous dams widely spread in China, which usually collapse suddenly and severely threaten the people’s safety. The landslide-caused dam-break events account for a greater percentage of the total dam failure events. Thus, it is necessary to evaluate the landslide risk using the scientific method. It is widely accepted that the mechanical simulation of landslide is a good method to evaluate the landslide risk. For this purpose, the assumption of the strength reduction method is adopted to cacluate the slope safety factor, which is also combined with the response surface method and monte-carlo method to perform the slope reliability in the present study. The major contributions in the present study are summarized as follows:(1) An artificial bee colony algorithm is used to optimize the Kriging model. The optimized Kriging model exhibits better curve-fitting performance than any other surrogate models. Then a hybrid structural reliability optimization algorithm is proposed. The algorithm is applied to calculate the gravity dam element reliability and the slope reliability. The result shows that the algorithm is very suitable for the structural reliability analysis.(2) The strength reduction method for the multiple sample points is also investigated in the present study. A linked list-based sifting method is proposed to calculate the slope safety factors of multiple sample points, which requires less time to calculate the failure probability of a slope. The proposed method combines the advantages of the sequential search and bisection search of the strength reduction method.(3) The steady saturated seepage-based slope reliability is investigated. The effect of the free surface on the slope reliability is studied.The steady saturated seepage model is alsto combined with the probabilistic flood theory to to study the downstream slope reliability of the Cheng-bi River earth dam.This methodology can reflect the real situation of dam safety.(4) The transient unsaturated seepage-based slope reliability is investigated. The transient unsaturated seepage model is adopted to calculate the slope reliability considering the rapid rise or drawdown of the upsteam water level. The effect of the matric suction on the slope reliability is also investigated in detail, which can be used for the relative engineer safety evaluation.