Shallow landslides have posed significant threats to humans around the world. In order to reduce landslide disaster risk, the effectiveness of early warning systems and hazard zonation work needs to be improved. This research attempted to couple a landslide simulation model (LS-RAPID model) and a hydrological model (Rainfall-Runoff-Inundation (RRI) model) to exploit the advantages of each model for simulating and predicting landslide hazard (location and timing). The pilot area is a small catchment where a shallow landslide happened in July 2015 after 2 days of heavy rain. The landslide buried 3 houses and killed 8 people in Cao Thang Ward, Halong City, Vietnam. A soil sample was collected from the sliding surface and tested using an undrained ring-shear apparatus ICL-2 in the undrained condition. A thickness map of the potential sliding material was interpolated from the relationship between the depth of sandy soil layer and slope (based on 12 soil drill locations) and updated through field surveys in the study area. Different pore water pressure ratio scenarios were applied in the LS-RAPID model to simulate in 3D the initiation and motion of the rapid shallow landslide to create different hazard maps. The subsurface water level was monitored at two locations on the top of the shallow landslide. Based on the observed subsurface water and rainfall data, the RRI model was calibrated and then integrated with the LS-RAPID scenarios to generate Risk Index maps. The simulation results from the newly proposed coupled hydrological-geotechnical framework were compared with those from the observed landslide hazard and showed the reliability to predict the spatial and temporal occurrence of landslide hazard. This could be very useful for supporting decision-makers in rainfall-induced landslide hazard early warning and land use planning.

中文翻译：

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预测浅层滑坡灾害的水文岩土耦合框架——以越南下龙市为例

浅层滑坡对世界各地的人类构成了重大威胁。为了降低滑坡灾害风险，需要提高预警系统和灾害分区工作的有效性。本研究试图将滑坡模拟模型（LS-RAPID 模型）和水文模型（降雨-径流-淹没 (RRI) 模型）结合起来，以利用每种模型的优势来模拟和预测滑坡灾害（位置和时间）。试点地区是一个小流域，2015 年 7 月，在连续两天的大雨后，发生了浅层滑坡。越南下龙市Cao Thang Ward的山体滑坡掩埋了3座房屋，造成8人死亡。从滑动表面收集土壤样品，并在不排水条件下使用不排水环剪装置 ICL-2 进行测试。潜在滑动材料的厚度图是根据砂土层深度与坡度之间的关系（基于 12 个土壤钻孔位置）内插的，并通过研究区的现场调查进行更新。在 LS-RAPID 模型中应用了不同的孔隙水压力比方案，以 3D 方式模拟快速浅层滑坡的发生和运动，以创建不同的灾害图。在浅层滑坡顶部的两个位置监测了地下水位。根据观测到的地下水和降雨数据，对 RRI 模型进行校准，然后与 LS-RAPID 场景集成以生成风险指数图。新提出的耦合水文岩土框架的模拟结果与观测到的滑坡灾害的模拟结果进行了比较，显示了预测滑坡灾害空间和时间发生的可靠性。这对于支持降雨诱发的滑坡灾害预警和土地利用规划的决策者非常有用。