Wall and ground movements in a braced excavation in clays and serviceability reliability of adjacent buildings.

摘要

The goal of this dissertation research is to establish an improved procedure for evaluating the excavation-induced ground settlement and building serviceability. This research covers several closely related topics. Firstly, a simplified small strain soil model developed by Hsieh et al. (2003), called the Modified Pseudo Plasticity (MPP) model, is evaluated for its capability and performance in the prediction of the excavation-induced ground deformation behavior using Finite Element Method (FEM). Secondly, for the development of the envisioned empirical models for estimating the excavation-induced wall and ground responses, a database of excavation case histories are compiled. To complement the database of excavation case histories, artificial data is also generated using FEM solutions, in which the well-calibrated MPP soil model was implemented. Thirdly, based on the established database a simplified semi-empirical model is developed for predicting the maximum wall deflection, the maximum surface settlement and the surface settlement profile caused by excavations in soft to medium clays. Further, a reliability-based approach is presented to assess the serviceability reliability of adjacent buildings based on the developed semi-empirical model. Finally, a procedure is proposed to make use of the filed observation data to update the settlement prediction at subsequent stages of excavation, and the serviceability reliability of the adjacent building is then updated accordingly.