Responses of excavation base under influences of confined aquifer: An analytical approach

Abstract

The hydraulic uplift is one of the disastrous failure patterns of the excavations in coastal area. However, current practice and previous research failed to properly consider the strength of the soils to resist the uplift force from the underlain confined aquifer, partly due to poor understanding of the stress and deformation of the soils in the excavation. This study derived an analytical solution for the excess pore water pressure response in the basal clay based on a large excavation model. The method considered both the unloading effects due to the excavation and the effects of confined water pressure in the underlain confined aquifer. In addition, the effective stress and the deformation of the basal soil can also be calculated. Parametric study based on the solution identified three types of factors individually affecting the pore water pressure response, effective stress development, and the deformation of the basal soil. The findings of this study can provide insight reference for understanding the response of the basal soils in the excavation.