CHAPTER 2

LITERATURE REVIEW

2.1 Introduction

The design considerations of an excavation system (Figures 2.1, 2.2, and 2.3) include avoiding failure of retaining structures due to overturning or toe kick out and limiting the base heave which may jeopardise the stability of the excavation support system. It is also necessary that the wall deformation is restricted to an acceptable limit, especially the long term behaviour as a result of the consolidation of the surrounding soil. Currently, the approaches in excavation support design are confined mainly to empirical and semi-empirical methods. Substantial research in Singapore on the development of empirical and numerical methods for determining the struts load, the stability of excavation and the ground movement had been carried out (Lee et al., 1984 and 1986; Chua, 1985). Previous studies on excavation are classified and summarised in Table 2.1. Field case studies on deep excavations with special emphasis on the behaviour of retained soil and the ground movement are surveyed in this chapter. Previous centrifuge studies of deep excavation are also reviewed in detail.