Evaluation of Pile Driving Effects on Slope Stability in Clay

Abstract

Pile driving can trigger slope failure, specifically in sensitive soil deposits or marginally stable slopes. Cases of slope failure during pile installation have been reported in countries such as Norway, Sweden and Canada where soft sensitive clay deposits are prevalent. Although a few approaches have been suggested to assess the factor of safety of a slope during pile driving, there is currently no standard method recognized by the geotechnical society to account for the reduction of safety factor of a slope as an effect of pile installation. Some approaches suggest using the excess pore pressure generated during pile driving to account for the reduction in soil strength (by reducing effective stresses), neglecting the change in total stresses. This paper discusses the accuracy of stability analysis methods currently in use for this problem by looking at stress changes in the soil during pile driving as well as using numerical analysis results. Importantly, the paper identifies the shortcomings regarding these approaches, thus allowing geo-engineers to understand the limitations of their analysis and the uncertainties in the models.