Application of plaxis 3D with the hardening soil and mohr coulomb model in simulation of diaphragm wall deflection

Abstract

Diaphragm wall deflection is considered one of the reasons for soil instability around excavation, causing serious consequences for neighboring constructions. Therefore, in the design and calculation of deep excavation, analyzing and simulating the diaphragm wall deflection between phases of excavation construction becomes very important. However, selecting an appropriate mathematical model and determining its input parameters affect the accuracy of the calculation results and their deviation from reality. In this article, the Hardening Soil (HS) model and the Mohr Coulomb (MC) model were used to simulate deflection calculations of diaphragm wall using Plaxis 3D and compared with data obtained from a real project in Ho Chi Minh City. The results showed that the stiffness parameter Eref50 was taken according to the formula Eref50 = 1000N for sandy soil (N: number of SPT blows), Eref50 = 500Su for cohesive soil (Su: undrained soil resistance) in the HS model, resulting in analysis of deflection that was quite compatible with actual data. In addition, the deflection of diaphragm wall varied inversely with its thickness, but this change was relatively small.