Optimising an output of a slip line field using a Chaotic Swamp Optimisation algorithm

In solving earth pressure problems, many input parameters are needed to account for more realistic soil properties and complex boundary conditions. Finding an optimal output while considering many inputs can be costly and time consuming. The input parameters themselves may be significantly uncertain due to lack of laboratory test data and variations in design and construction stages. Adopting an optimisation technique can be useful in such a problem. In this study, a chaotic particle swamp optimisation (CPSO) algorithm is applied to three different earth pressure problems, i. e. an excavation problem, a plane strain tunnel problem and a suffusion sinkhole problem, to determine their global optimal outputs and corresponding input parameters. The problems are solved using a slip line theory satisfying static equilibrium and the Mohr-Coulomb failure criterion. This improved PSO algorithm is found to show better performances, in accuracy and computational effort, compared to conventional Monte Carlo simulations (MCS).