Bottom Reinforcement in Braced Excavations: Coupled Analysis and New Method for Basal-Heave Stability Study

Soil-cement bottom reinforcement is commonly used in braced excavations in soft soils, so that ground displacements can be reduced and excavation safety against bottom failure increase. However, there is a lack of studies in the literature regarding such reinforced excavations in which the stability against bottom heave is analysed through mechanical-hydraulic coupled modelling. In the paper, in order to contribute to overcome such deficiency, a braced excavation in soft soil, incorporating a jet-grout base slab, is analysed. A finite element code, which incorporates the above-mentioned features, is used and a new method for basal stability analysis - which utilizes the numerical results obtained by the finite element code - is proposed and applied. Two cases of the same problem, with and without soil-cement bottom slab, are compared.