Complex method (CM) of traditional optimization methods combined with simulated annealing (SA) of intelligent optimization methods; and a new type of intelligent computation method

complex simulated annealing (CSA)

was developed. Simulating analysis results show that the CSA has outstanding advantages in searching performance compared with the complex method or the simulated annealing. In addition

an optimization design model for cement-soil retaining wall (CSRW) was set up according to Chinese design codes; and the CSA was successfully applied to the optimization design of CSRW. Two case studies were given to verify the proposed method. The comparing computation results show that the proposed optimization method is feasible and reliable. Finally

the influence of reinforcement of passive earth pressure area located inside foundation pit on the embedded depth and effective breadth of CSRW was discussed.