Analytical solution for slope instability assessment considering impact of confined aquifer

Abstract

An analytical approach was presented for estimating the factor of safety (F_S) for slope failure, with consideration of the impact of a confined aquifer. An upward-moving wetting front from the confined water was assumed and the pore water pressure distribution was then estimated and used to obtain the analytical expression of F_S. Then, the validation of the theoretical analysis was applied based on an actual case in Hong Kong. It is shown that the presence of a confined aquifer leads to a lower F_S value, and the impact rate of hydrostatic pressure on F_S increases as the confined water pressure increases, approaching to a maximum value determined by the ratio of water density to saturated soil density. It is also presented that the contribution of hydrostatic pressure and hydrodynamic pressure to the slope stability vary with the confined aquifer pressure.

Keywords

confined/artesian groundwater / slope stability / factor of safety / analytical approach

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