Finite element simulation of deep excavation in soft cohesive soils using an enhanced anisotropic bounding surface model

Mechanical behavior of geomaterials directly affects all geotechnical construction activities, such as embankments and excavation. The nature of soils is complex, and its behavior is affected by many factors, including the fact that initial stresses existing in the natural ground are anisotropic. It is critical to develop a model that captures the salient features of soils. This study is concerned with implementing an enhanced nonassociative anisotropic bounding surface model, which has exhibited a great potential to realistically describe the behavior of different types of cohesive soils, into a general purpose finite element software PLAXIS, and using it to simulate deep excavation in soft cohesive soils. The formulations are based on nonassociative flow, but the model degenerates to that of associative flow in simpler form. The simulations using associative and nonassociative formulations are also presented. The selected deep excavation case included the Taipei National Enterprise Center site. The results demonstrate the potential of the enhanced anisotropic bounding surface model for realistically simulating engineering applications involving ground response induced by deep excavations.