Effects of jet grouting slabs on responses for deep braced excavations

Abstract

Jet grouting slabs are widely used in deep excavations owing to their effectiveness for reducing the deflection of the diaphragm wall and the prop forces acting on the struts and improving the basal-heave stability. In this paper, according to case histories in Singapore, a series of finite-element numerical simulations are performed to evaluate the effects of jet grouting slabs on responses to deep braced excavations. On the basis of a parametric sensitivity study, a reasonable thickness of jet grouting slabs is proposed. The effects of the wall depth, wall stiffness, soft-clay thickness, and stiffness on the performance of the jet grouting slabs are assessed by comparing and analyzing a series of simulation results. It is found that the soft-clay thickness significantly affects the wall deflection and basal heave in deep excavation. During the design of support structures, soil profiles should be considered first. The findings of this study provide a reference and guidance for the support system design of similar projects.