Numerical Modelling of Gravel Compaction Piles in Soft Peaty Clay

Soft soil has become a major challenge in expressway construction and Gravel Compaction Piles (GCP) have been used as one of the most common ground improvement techniques to overcome this problem. However, the knowledge on the behaviour of GCP improved ground under drain condition remains limited. Hence, the most effective way to study the behaviour of GCP improved ground is through numerical modelling. Accurate modelling of the existing ground conditions is critical for precise analysis, even though replicating the exact ground conditions is not entirely feasible. Based on the simplification and time consumption, PLAXIS-2D software has been used in this study for numerical modelling. In order to convert the 3D actual scenario into 2D condition, two types of conversion methods, namely Geometry conversion and Parameter conversion methods, have been used. The accuracy of above conversion methods was verified by comparing the numerical model results with field data collected from expressway projects in Sri Lanka. A detailed analysis of settlement and pore water pressure behaviour was used to identify the most suitable conversion method for local context. Based on the results it can be concluded that the parameter conversion method is the most effective approach for accurately representing the behaviour of GCP improved ground in numerical modelling.