Stability Analysis By Genetic Algorithm And Reliability Study Of Earth Slopes Under Earthquake

The criterion on how to evaluate the stability of an earth slope and the way to find the critical slip surface are the main purpose in aseismic analysis of earth slopes.Genetic-Algorithm was used to determine the minimum safety factor and the critical slip surface of earth slope in this paper. By recalculating the Pai-Ho main dam, the algorithm proved to be powerful in solving such problem.Because the intensity of clay is not a constant during earthquake, the intensity attenuation of clay must be considered in aseismic analysis of earth slope. Considering both the acceleration time history of earthquake and the intensity attenuation time history of clay, the Pai-Ho dam was calculated with Newmark's method in this paper.Having not consider the variety and randomness of design parameters, there were much limitation in the traditional safety-factor method in evaluating the long-time stability of earth slopes. To solve the problem, reliability was used to evaluate the life-long stability of earth slopes. Considering the local seismic risk, the variety of earth parameter and the variety of seismic grade, reliability was used to evaluate the 50-year long stability of an earth slope in QuanZhou.After the study, some conclusions can be draw below:(1) Genetic-Algorithm is powerful in finding the minimum safety factor and the critical slip surface. The result is quite tally with the surveyed one.(2) The minimum safety factor and the critical slip surface are determined by both the acceleration time history of earthquake and the attenuation time history of clay. The maximum acceleration and minimum shear intensity should be carefully used in aseismic stability design of earth slopes.(3) Reliability is more effective in evaluate the long-time safety of earth slope than safety factor.