Slopes covered with unsaturated shallow pyroclastic deposits, lying upon fractured limestone bedrock, are widespread in the mountains around Naples (southern Italy). Rainfall infiltration, reducing soil suction, eventually triggers shallow landslides. While drastic reduction of suction is unanimously recognized as the triggering mechanism, there is still debate about the hydrological processes controlling slope drainage and causing the establishment of landslide predisposing conditions. Field observations at the slope of Cervinara suggested that temporary storage of water in a perched aquifer, in the upper part of the fractured bedrock, may affect the leakage through the soil-bedrock interface. Hence, a physically based model, coupling flows in the unsaturated soil cover and in the perched aquifer, has been applied to three large rainfall events which occurred in December 1999 (when a landslide was triggered), January 2009, and November 2012. The results highlight that the different responses of soil and aquifer to precipitations, related not only to rainfall event characteristics (i.e., duration and mean intensity) but also to the initial conditions of the slope, determined by antecedent precipitations, can play a prominent role in the triggering of landslides. In fact, further simulations with synthetic rainfall events and different initial conditions provide a possible interpretation of the triggering of the landslide of December 1999, indicating that a soil profile with dry conditions at the base and a low level in the perched aquifer, typical of late autumn, can impede the drainage of infiltrating water through the soil-bedrock interface, thus favoring the build-up of pore pressure within the soil cover.

中文翻译：

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非饱和和饱和地下水流耦合建模预测火山碎屑覆盖斜坡浅层滑坡

覆盖着不饱和浅层火山碎屑沉积物的斜坡位于破碎的石灰岩基岩上，广泛存在于那不勒斯（意大利南部）周围的山区。降雨入渗，减少土壤吸力，最终引发浅层滑坡。虽然吸力的急剧减少被一致认为是触发机制，但关于控制边坡排水和导致滑坡诱发条件的建立的水文过程仍然存在争议。在 Cervinara 斜坡的实地观察表明，在断裂基岩上部的栖息含水层中临时储存水可能会影响通过土壤-基岩界面的渗漏。因此，一个基于物理的模型，非饱和土壤覆盖层和栖息含水层中的耦合流动，已应用于 1999 年 12 月（触发滑坡时）、2009 年 1 月和 2012 年 11 月的 3 次大降雨事件。 结果突出表明，土壤和含水层对降水的不同响应，不仅与降雨事件特征有关（即持续时间和平均强度）以及由前期降水决定的斜坡的初始条件，可以在滑坡的触发中发挥重要作用。事实上，对合成降雨事件和不同初始条件的进一步模拟为 1999 年 12 月滑坡的触发提供了可能的解释，表明底部干燥的土壤剖面和栖息含水层中的低水位，典型的晚期秋天，