Robust design of siphon drainage method for stabilizing rainfall-induced landslides

Drainage is a critical and cost-effective method to stabilize rainfall-induced landslide. In order to improve the efficiency and sustainability of drainage system, a new siphon drainage method is presented in this paper. Factor of safety (FOS) under the action of a given siphon drainage design, computed using Morgenstern-Price method, was used to evaluate the design effectiveness. A guidance for the design of this new siphon drainage method was established based on the robust design concept. Signal-to-noise ratio, which is a function of mean and standard deviation of FOS and related to the uncertainty of shear strength parameters of slip surface, is used as a measure of the design robustness. A framework based on the concept of robust design is proposed for determining the most optimal siphon drainage design considering multiple objectives including safety, cost, design robustness, and drain effectiveness. This framework is illustrated with a case study, the Hongpucun landslide in Zhejiang Province, China. Based on the outcome of this study, the optimal siphon drainage design is obtained.