The presence of capillary pressure in unsaturated soils may, under certain circumstances, significantly affect the stability of a slope and the safety of a structure standing in the vicinity of its crest. More specifically, the change in saturation induced by a rainfall event may directly influence the value of apparent soil cohesion potentially resulting in excessive permanent slope displacements and subsequent structural damages for the structure standing on it. Under these considerations, this study aims at the vulnerability assessment of typical reinforced concrete (RC) buildings on precarious slopes subjected to rainfall induced landslide hazard. The proposed methodology is based on a two-step numerical analysis procedure. First, the permanent absolute and differential ground displacement time histories at the assumed building location within the landslide zone are evaluated performing coupled mechanical-flow analysis of a generic initially unsaturated natural slope configuration considering the employment of different rainfall events of increased intensity at the surface of the slope model. Different soil properties of the surface layer are considered to represent silty and soft clayey soil material. Appropriate analytical relationships between the rainfall intensity and its duration and the computed permanent displacements are extracted. Then, a series of nonlinear static time history analyses are performed for reference low and mid-rise, low-code RC bare and infilled frame buildings located next to the slope's crest to assess their fragility. The buildings’ response assessed using appropriate engineering demand parameters (EDPs) to account for both the global flexural and local shear demand are statistically correlated with predefined damage limit states to construct the fragility functions. To facilitate the applicability of the proposed methodology within a quantitative landslide risk assessment framework, vulnerability curves are finally developed to quantify the expected direct losses in normalised cost terms.

在某些情况下，非饱和土壤中毛细管压力的存在可能会显着影响斜坡的稳定性和位于斜坡顶部附近的结构的安全性。更具体地说，降雨事件引起的饱和度变化可能直接影响表观土壤凝聚力的值，可能导致过度的永久斜坡位移和随后的结构损坏。在这些考虑下，本研究旨在对受降雨诱发的滑坡灾害的不稳定斜坡上的典型钢筋混凝土 (RC) 建筑物进行脆弱性评估。所提出的方法基于两步数值分析程序。第一的，评估滑坡区内假定建筑物位置的永久绝对和差分地面位移时间历程 考虑在斜坡表面使用不同的强度增加的降雨事件，对通用初始非饱和天然斜坡配置执行耦合机械流分析模型。表层的不同土壤性质被认为代表粉质和软粘土材料。提取降雨强度及其持续时间和计算的永久位移之间的适当分析关系。然后，对位于坡顶附近的参考中低层、低代码 RC 裸露和填充框架建筑物进行了一系列非线性静态时程分析，以评估其脆弱性。使用适当的工程需求参数 (EDP) 评估建筑物的响应以考虑全局弯曲和局部剪切需求，在统计上与预定义的损坏极限状态相关，以构建脆弱性函数。为了促进所提议方法在定量滑坡风险评估框架内的适用性，最终开发了脆弱性曲线以量化标准化成本项下的预期直接损失。