Uniqueness of Solution in the Excavation Analysis with Elasto-Plastic Soil Spring model

An analysis method of the behavior of earth retaining structures during excavation is developed based on finite element modeling of the retaining structure and the ground medium which is represented as elasto-plastic Winkler model. It is found that the unique solution independent of the excavation steps cannot be guaranteed in the excavation problem of monotonically shrinking elasto-plastic domain if a conventional excavation simulation procedure is employed. In this paper, the cause of the non-unique-ness of the solution is clarified and a new excavation simulation procedure is proposed. It renders unique solution in the case of monotonically shrinking elasto-plastic domain which is modeled as elasto-plastic soil spring.