Modified PSO-FLAC Coupling Optimum Method and Application in Underground Engineering Design

To improve the performance of PSO (Particle Swarm Optimization), a modified algorithm named CDPSO (Colony Density Particle Swarm Optimization) is presented based on the comprehension that the space density character of particles embodies the convergence speed and global optimization ability of particle swarm. By the way of adopting dynamic nonconforming inertia coefficient and acceleration coefficient according to density factor, a high efficient global search PSO algorithm is achieved. For the purpose of application in underground engineering design conveniently, a new method of coupling CDPSO and FLAC, an excellent aided design software in underground engineering, is put forward. The CDPSO-FLAC coupling method implements the cooperation between optimization searching and safety calculation of engineering by embedding the CDPSO algorithm into computational kernel of FLAC. The method is used successfully in the support design of a northwest tunnel in China.