Author(s): Huawen Xiao; Yaodong Zhang
Linked Author(s): Yaodong Zhang
Keywords: Rainfall transient seepage groundwater level ponding dredge material capping sand revetment
Abstract: Climate change, including sea level rise and extreme weather, is becoming increasingly common. Consequently, the issues like rainfall-induced slope failure, piping and ponding are becoming more significant. The planning and design of land reclamation works shall take this into account and include necessary measures to mitigate the impact. However, the rainfall induced seepage and ground water level (GWL) change is a complex problem and could be more complicated for reclamation project as it usually involves lower permeability dredge material at the bottom and higher permeability sandfill at the top as sand cap. Many factors could contribute to the above-mentioned problem, which may include initial GWL, permeability of sandfill material, rainfall intensity and duration and capping sand thickness. In this study, parametric study was carried out through transient seepage analysis to investigate the impact of those factors on the seepage and ground water level change due to rainfall. Based on the transient analysis, stability analysis was conducted to assess the impact of seepage and GWL change on the stability of revetment. Results showed that, for 5 days rainfall, lower initial GWL more easily induces earlier longer perched ponding than higher initial GWL while higher initial GWL more easily initiates full ponding in reclamation area or higher GWL rise in sand bund area at late stage of rainfall. Under higher initial GWL, sandfill permeability has more significant effect on GWL and ponding. Results also indicated that the impact of seepage and GWL change on the stability of revetment seems insignificant.
Year: 2025