Modeling small-strain behavior of Taipei clays for finite element analysis of braced excavations

We examine the small-strain behavior of Taipei clays in braced excavation through a detailed analysis of a well-documented case history. Specifically, we analyze the case of the Taipei National Enterprise Center (TNEC) excavation using two soil models, the Modified Cam-clay model (MCC) and the three-Surface Kinematic Hardening model (3-SKH). Our finite element analysis includes a consideration of the over-consolidated stress state and the high initial shear modulus of the clay. Results show that the observed wall deflection and surface settlement can be satisfactorily predicted simultaneously using the 3-SKH model. This is an improvement on the MCC model, for which only wall deflection, not ground settlement, can be accurately predicted. This study re-confirms the importance of considering small-strain non-linear behavior for the over-consolidated stress state in finite element analyses of braced excavation responses.