Effect of hysteresis on the stability of an embankment under transient seepage

International Symposium on Geohazards and Geomechanics 2015

地球科学;生态环境科学

Liu, Kang^1 ; Vardon, Philip J.^1 ; Arnold, Patrick^1 ; Hicks, Michael A.^1

Section of Geo-Engineering, Department of Geoscience and Engineering, Delft University of Technology, Delft, Netherlands^1

关键词: Dangerous situations;    Slope stability analysis;    Soil water retention;    Transient seepage;    Unsaturated soil;    Unsaturated zone;    Volumetric water content;    Water-level fluctuation;   

Others  :  https://iopscience.iop.org/article/10.1088/1755-1315/26/1/012013/pdf
DOI  :  10.1088/1755-1315/26/1/012013

学科分类：环境科学（综合）

来源: IOP

【 摘 要 】

Hysteresis is a well-known phenomenon that exists in the soil water retention behaviour of unsaturated soils. However, there is little research on the effects of hysteresis on slope stability. If included in slope stability analyses, commonly the suction in the unsaturated zone is taken as non-hysteretic. In this paper, the authors investigate the effect of hysteresis on the stability of an embankment under transient seepage. A scenario of water level fluctuation has been assessed, in which a cyclic external water level fluctuates between a low and high level. It was found that the factor of safety (FOS), the volumetric water content and the suction in the unsaturated zone are significantly affected by hysteresis. It was also found that, when the period of water level fluctuation in one cycle is relatively small, there is little difference in the FOS between the hysteretic case and non-hysteretic case. However, when the period exceeds a certain threshold value, significant differences between these two cases can be observed. Compared to the case in which hysteresis is considered, the FOS is higher in the case which does not consider hysteresis. This suggests that the non-hysteretic case may overestimate slope stability, leading to a potentially dangerous situation. Moreover, the period under which there emerge large differences between the hysteretic and non-hysteretic case is strongly related to the magnitude of hydraulic conductivity and the period of the cyclic water level fluctuation.