Modelling of Lateral Movement in Soft Soil Using Hardening Soil Model

Excavation in soft soil will lead to changes in stress state ground mass and subsequent ground losses inevitably occur. These changes affect the surrounding ground in the form of lateral movement which eventually impose direct strains onto nearby structures and can cause pile deviation and cracks. This study models the lateral movement in soft clay due to excavation using finite element simulation known asPLAXIS. Two types of isotropic models in PLAXIS are compared that are Hardening soil Model and Mohr Coulomb Model. The soft clay was collected from a site location in Selangor, Malaysia and the physical and engineering properties test were firstly determined. For simulation in PLAXIS, a geometry model which consists of sand and clay layer was used and a vertical sheet pile was driven downwards until bottom of the soil layer. Excavations were done in stages on one side of the soil retained induced horizontal displacement to the sheet pile until resulted failure to occur. From the results obtained, it can be concluded that Mohr-Coulomb model are almost equal to Hardening-Soil model in terms of horizontal displacements. However, for the soil stresses, the researcher found that the percentage differences between the both models are higher which is caused by characteristic of Hardening-Soil model that accounted fortress dependency of stiffness increase with pressure.