Abstract
In this paper, it aims to examine impacts from three-dimensional effect on the wall deflection induced by a deep excavation in Kaohsiung city, Taiwan. The commercial software PLAXIS 3D was used as a numerical tool for 3D finite element analyses in this study. First, a benchmark analysis was performed to simulate a case history of deep excavation in thick layers of sand (Case A) to verify the performance of 3D numerical analysis model in predicting the wall displacements. It is aware that there is a little limitation in prediction of the wall movements by using a constitutive soil model having single elastic modulus. Next, a series of parametric studies that uses the same input parameters as the benchmark analysis was conducted to model the excavation of Case A with various values of excavation length (L) and width (B). From these parametric studies, plane strain ratio (PSR), which is the ratio of the maximum wall deflection of a certain section to the maximum wall deflection of the section under the plane strain condition, was determined with various values of distance from evaluated section to the excavation corner (d), length (L) and width (B) of excavation. A relationship between PSR, d and ratio of B/L was thus interpreted. It is summarized that PSR is smaller than in sand rather than in clay for B/L more than 1.0, but it is larger than in sand rather than in clay for B/L less than 0.5. Further verification may have to be delivered later in order to explore the reason for the difference.
