Researches Of The Chaotic Particle Swarm Optimization Design Method For Group Piles Under Vertical Loadings

The pile-raft foundation is used more and more widely with development of the high-rise buildings. Because of its high cost, immature design theory and dominant distinction between different design schemes of the same building, the optimization design method for pile foundation to reduce the cost takes more and more attention.The optimization design of pile foundation includes the computation theory of the pile foundation, optimized mathematical model, optimum algorithm and the realization of the programmed calculate. Any aspect plays an important role in the optimization method.According to the computation theory of the new Code for Pile Foundation (2006), the chaotic particle swarm optimization design method for group piles is discussed. The optimal mathematical model established in this paper, which takes the amount of concrete and steel into account, conforms to the reality better compared to the former mathematical model. Analysis of the calculation example behind shows that the foundation cost measured only by the amount of concrete is not correct, too. The optimization algorithm of the chaos theory and Particle Swarm, contrasts its prominent merit including simple parameters involved, fast and effective convergence and avoiding falling into partial optimal solution and so on. Also a computer Program of optimum design is established using FORTRAN90 software.The rule which the parameters of the group-piles foundation influence the cost , has be obtained by the optimization analysis of the calculation example, using the optimum method and program in this paper.Finally, the optimum method proposed in this paper has obvious efficiency in the design of the pile foundation through an optimum design of an project example. This paper shows the optimization method is feasible.