Stability Analysis Of Slope Under Complex Stress Conditions Based On MPGA

Slope stability analysis runs through the geotechnical engineering and the whole process of construction, for a long time, which is always hotspot and difficulty in research of slope engineering, meanwhile it has made the rich achievement, however, some serious slope accident warned us that slope stability studies must be further deepened.This paper combines the finite element method with Multi-population genetic algorithm (MPGA) by using vector sum factor of safety, which builds a general model of slope stability analysis under complex stress conditions. And writing programs, as follows:Firstly, application the MIDAS-GTS to get the real stress field of slope. Secondly, by using vector sum factor of safety as the target function of the genetic algorithm, to construct the fitness function of genetic algorithm, and introduce the penalty mechanism to improve search efficiency. Finally, create the initial population dynamically, which gradually become dense, and increase sliding surface constraint conditions, which can be a range of mutation and criterion of penalty strategy. Through a series of artificial operator such as:selection, crossover, mutation and migration, realize the evolution. At last, obtain the minimum safety coefficient and the most dangerous sliding surface.Through a typical example verify the reliability of this method, and through analysis reached the following conclusions:(1) This method is suitable for slope stability analysis under complex stress conditions, and can be used to analysis the process of slope reinforcement.(2) The evolution curve of MPGA is smoothly, and the minimum safety factor of the first generation of the initial population are very close to the global optimal solution, it shows that this method is very efficient, and reduce the effect of the control parameters on the optimization results.(3) Minimum safety factor of slope reinforcement process does not necessarily appear in the overall supporting, it most likely to appear in the process of reinforcement. Therefore, Slope stability analysis must be attention in the process of support, Step-construction on the stability is helpful to ensure slope stability analysis of supporting process.