Advance Modeling of Soil Cement Mixing for Deep Excavation Using Plaxis 2D Concrete Model

Wet speed mixing (WSM) and deep cement mixing (DCM) are adopted as ground improvements on soft soil to support temporary earth retaining walls below excavation level for deep excavation. WSM and DCM are commonly modeled using Plaxis Mohr–coulomb model (method B) with undrained shear strength. Concrete model is adopted to model ground improvement with more realistic stress distribution to account for non-linearity of material behavior, and model tension in elastic until the tensile strength is reached. Case study of model WSM and DCM by using both Mohr–coulomb model and Concrete model for two projects successfully completed at reclamation land overlaying on soft Kallang Formation are presented, one is about 16 m deep excavation with temporary steel soldier pile wall lagged with sheet piles supported by 4-layer temporary strutting system and 4 m thick DCM at base of excavation. The other is for 19 m deep excavation with temporary steel pipe piles wall support by two-layer temporary steel struts and 4–11 m thick WSM at base of excavation.