Response Surface Based-Robust Design of Supported Excavation Considering Multiple Failure Modes

The robust geotechnical design (RGD) is widely used in retaining wall, foundation and deep excavation because it can balance construction cost and structural safety well. For deep braced excavation, it was well recognized as a complex system design in geotechnical community because its multiple failure modes and high uncertainty. In this study, responses surface based-robust design method (RSM-RGD) was applied in the design of supported excavation. Different from traditional robust design, the responses surfaces as an alternative model of finite element model was used to establish failure functions. Both one kind of ultimate limit failure mode and two kinds of serviceability limit failure modes of retaining system were taken into account. Via proposed method, a multi-objective optimization framework was modeled to find the optimal design with lower construction cost and higher robustness and safety. Finally, the whole steps of proposed method were illustrated by a case study. The result indicated that the multi-objective optimization model and genetic algorithm has an efficient effort on solving Pareto frontiers.

Keywords: responses surface method, system reliability, robust geotechnical design, multi-objective optimization.