2D & 3D numerical analyses of a deep excavation supported by LC columns

Paper in proceeding, 2023

This paper presents finite element simulations of an instrumented deep excavation in soft clay. The excavation is supported with sheet pile walls utilising lime-cement (LC) columns in the passive side. The measured deformations were backcalculated using a two-dimensional (2D) plane strain model, as well as a full three-dimensional (3D) model, in conjunction with fully coupled consolidation analysis. Prescribed volumetric strain was used to capture the installation effects of the LC columns. Advanced constitutive models were utilised for both the natural and stabilised clay. The model parameters used to simulate LC columns were derived and calibrated using triaxial extension tests. The 2D analysis was performed using a simple stiffness averaging technique, whereas in the 3D analysis the columns and the soil were modelled separately. The displacement profile captured by the inclinometer located at the intersection with the nearby excavation site could be captured only with the 3D analysis. The numerical results of both the 2D and the 3D analyses indicate that the inclusion of installation effects was crucial to replicate the field response.