Abstract

Sea level drawdown may lead to the stability decrease and even the failure of coastal clay slopes. Since few attempts have been made to illustrate the impact of sea level drawdown on coastal slope stability considering three-dimensional (3 D) geometry and nonlinear strength, this paper extended 3 D limit analysis approach with nonlinear criterion for slope stability under different sea level drawdown conditions. The least upper bound on stability number was derived by using an optimization procedure. Stability charts were presented and the influences of sea level drawdown on slope stability were illustrated. The drops of sea levels in three cases were found to have different effects on the decreases in slope stability caused by nonlinear parameters. 3 D slope tends to be unstable in the case of rapid drawdown, but it will become stable when the inside water drops after sea level has rapidly decreased. In the case of sea level slow drawdown, slope stability will reduce to minimum and then increase. Effects of sea level drawdowns on slope stability become less significant for slope soils with obvious nonlinear strengths. Certain reinforcement measures can be taken to improve the stability of coastal slopes undergoing sea level rapid drawdown or slow drawdown.

摘要

海平面下降可能导致沿海粘土边坡稳定性下降甚至破坏。由于很少有人尝试在考虑三维 (3 D) 几何和非线性强度的情况下说明海平面下降对海岸边坡稳定性的影响，本文扩展了具有非线性准则的 3 D 极限分析方法，用于不同海平面下降下的边坡稳定性状况。稳定性数的最小上限是通过使用优化程序得出的。提出了稳定性图表，并说明了海平面下降对边坡稳定性的影响。发现三种情况下的海平面下降对非线性参数引起的边坡稳定性下降有不同的影响。快速回撤的情况下，3D斜率趋于不稳定，但当海平面迅速下降后内部水量下降时，它就会变得稳定。在海平面缓慢下降的情况下，边坡稳定性会先降到最低，然后再升高。对于具有明显非线性强度的边坡土，海平面下降对边坡稳定性的影响变得不那么显着。可以采取一定的加固措施来提高海平面快速下降或缓慢下降的海岸边坡的稳定性。