Stability Analysis Of Three-dimensional Slope Under Complex Stress Conditions

The stability analysis of slope on 3D FEM considering spatial effect, which can be more truly reflect the actual form of slope. In most cases, the vast majority of the slip surface have a 3D effect in the nature. Therefore, it is not in accord with the practical engineering to study the slope stability by using the traditional analysis method of 2D. The slope accident always causing huge casualties and economic losses to humans. Natural disasters are one of the main reason to landslide, in addition,for the the slope engineering or foundation pit engineering, during the construction process of reinforcement, excavation, also tend to occur serious accident due to instability.As time goes by, reinforcement slope can not always guarantee its stability constant, we need to regularly monitor and make a reasonable evaluate the stability to ensure its security later.Therefore, the study of stability analysis of three-dimensional slope under complex stress conditions is imperative.In this paper, multi-population genetic algorithm(MPGA) is used in three-dimensional slope stability analysis, which combined with the finite element method to establish a new method, and also developed a corresponding procedure.The specific method in this paper is as follows:(1) To take ABAQUS finite element analysis software as an example, using it to establish a three-dimensional numerical model of slope to obtain three-dimensional stress field.(2) Constructing chromosome by the discrete points of potential slip surface, safety factor is then calculated by the three-dimensional stress field using vector sum analysis method, then combined with safety factor to build the fitness function, to provide a variety of group fitness for the evolution of the genetic algorithm.(3) Generating a set of sliding surface as the initial population according to the concept of dynamic domains, and to identify constraints sliding surface, set the basic operating parameters of genetic algorithm, such as various parameters and operator definition of genetic algorithms. Through a series of genetic manipulation, to achieve the evolutionary on the basis of fitness value,iterative methods include selection operator, crossover and mutation operators which can further control and limit the chromosome, so that It can generate the target sliding surface of three-dimensional slope comply with the optimization and generate the minimum safety factor ultimately.Finally, by the stability analysis of the classical examples and engineering example the method is verified to be rational. It’s also proved that the method can beapplied in reinforced slopes under complex stress conditions by analyzing the stability of soil-nailed 3D slope. The superiority of the method is devoid of all of the artificial assumptions of three-dimensional limit equilibrium method in theory, which don’t need to assume that the sliding surface shape To overcome the difficult problem of slip face search.It is not necessary to assume the shape of the slip surface, but the stress field of the slope or foundation pit is obtained by the finite element method, and then combined with the intelligent algorithm to search the sliding surface.