Monte-Carlo simulation of dike stability based on a coupled hydro-stability model

With a large network of dikes that in the future will protect up to 15% of the worlds population from flooding, more extreme river discharges that result from climate change will dramatically increase the flood risk of these protected societies. Precise calculations of dike stability under adverse loading conditions will become increasingly important, though the hydrological impacts on dike stability, particularly the effects of groundwater flow, are often oversimplified in stability calculations. In order to better take account of groundwater flow processes, we use a coupled hydro-stability model to indicate relations between the geometry, subsurface materials, groundwater hydrology and stability of a dike. To calculate the stability, the most adverse drained loading conditions are applied to soil slip and basal sliding mechanisms. A database created by an extensive Monte Carlo analysis provides evidence for relations between geometry, material characteristics, hydrology and stability for three different failure processes. The database contains parameter combinations and the corresponding safety factor F. The database can be used to estimate failure probabilities for dike stretches that have not been assessed in detail, while including the uncertainties caused by a lack of in-situ data.凭借庞大的堤防（dike）网络，未来可保护全球15%的人口免受洪涝灾害。然而气候变化引发的愈发极端的河流径流量，将大幅抬升这些受保护区域的洪涝风险。极端荷载工况下堤防稳定性的精准计算愈发关键，但当前稳定性分析中，水文过程对堤防稳定性的影响——尤其是地下水流的作用——常被过度简化。为更好地纳入地下水流过程的影响，我们采用耦合水文稳定性模型（coupled hydro-stability model），以揭示堤防几何形态、地下岩土材料、地下水文特征与稳定性之间的关联。在稳定性计算中，针对土体滑移（soil slip）与基底滑动（basal sliding）两种破坏机制，采用最不利的排水荷载工况。通过大规模蒙特卡洛分析构建的数据库，佐证了三类不同破坏过程下，几何参数、材料特性、水文条件与堤防稳定性之间的相关关系。该数据库包含各类参数组合及对应的安全系数（safety factor）F。此数据库可用于估算未开展详细评估的堤段的失效概率，同时可纳入因缺乏原位（in-situ）数据所带来的不确定性。