DEVELOPMENT AND APPLICATION OF TECHNIQUES FOR POPULATION-BASED BACK-ANALYSIS OF GEOTECHNICAL EXCAVATIONS

Abstract

Construction activities for underground structures are usually monitored. In addition to the information obtained from site investigations and laboratory tests, field-response measurements (such as wall deflections, ground settlements and strut forces) provide knowledge of material parameter values and the overall behaviour of underground structures. The procedure whereby material parameter values are estimated from the field-response measurements is often called back analysis. With an effective back analysis implementation, engineers are able to make informed decisions and subsequently achieve a potential reduction in construction risks and costs. This thesis focuses on the development and application of a range of strategies for back analysing excavation response. These methodologies consist of (i) a technique to quantify three-dimensional effects of excavation, (ii) a population-based optimisation algorithm and (iii) a hierarchical algorithm to select field-response measurements for back analysis. Three data-interpretation methods are implemented and compared in this thesis.