Effect of sea level drawdown on coastal clay slope stability considering two strength criteria

Abstract

For coastal slopes, the effects of sea level drawdown on slope stabilities with linear and nonlinear criteria are lack of research. This paper employed tangential method to carry out limit analysis for coastal slope stability with Power-law criterion. The upper bound solutions were derived on base of work-energy equations for two cases of sea level rapid drawdown and sea level slow drawdown. For two slope examples, presented comparative charts illustrated that slope critical height associated with nonlinear or linear criterion decreases in case of sea level rapid drawdown. As sea level rapidly drops near slope toe, using linear criterion will significantly overestimate the stability of steep slopes. The slip surface with nonlinear criterion becomes shallower, and the slip surface with linear criterion becomes deeper first and then remains unchanged. Under the condition of sea level slow drawdown, nonlinear and linear solutions decrease first and then increase, and their maximum declines reach about 34% and 42%, respectively. The slip surfaces associated with nonlinear and linear criteria both become slightly shallower. 3D geometry has a more obvious impact on the stability of gentle slopes with B/H ≤ 15. The presented results can provide guidance on disaster prevention and control for coastal slopes.