A very large percentage of the Italian municipalities is exposed to landslides, floods, and/or coastal erosion, according to the 2021 edition of the Report on hydrogeological instability in Italy. Even the south-eastern area of the country, the Apulia Region, is affected by different geo-hydrological hazards, with a concentration of landslides in the north-western portion, named the Daunia Apennine sector. Such a significant exposure to landslide hazard imposes the need of defining reliable quantitative methodologies to assess landslide susceptibility at both the slope scale and urban scale, so that appropriate land planning policies, as well as effective prevention and mitigation measures, can be implemented according to a more rational approach. The main purpose of this study is to propose a physically-based methodology, at the urban area scale, aimed at assessing landslide susceptibility, for both shallow and deep instability processes affecting almost all the urban areas in the Daunia Apennines. The proposed methodology has been applied to the municipality of Carlantino (FG) as a test case study, using the available geological and geomorphological maps as well as the soil physical and mechanical data. A three-dimensional geotechnical model, 2.5 km2 wide, including the Carlantino urban area and the slopes surrounding the town, was created. Later on, a three-dimensional limit equilibrium analysis, taking into account the equilibrium conditions both in the slip and the transverse directions, was performed to obtain a mechanically-based map of safety factors at the urban area scale. The results of this study, obtained for three different scenarios related to the assumed depth of the groundwater table, allowed the identification of the areas more susceptible to landsliding, i.e. characterised by lower safety factor values. The proposed 3D approach represents a significant advancement with respect to the traditional 2D stability calculation methods in terms of accuracy of the representative geometrical and geological model, which is assumed to fit more effectively the complexity of the actual slope conditions. Moreover, the methodology can have significant practical applications, since the corresponding results provide a prompt overview of the slope stability conditions of an overall urban area and can be directly used for urban planning as well as risk management activities. Based on a comparison against geomorphological evidence and remote sensing data, this approach has proven to be a valuable tool to support landslide susceptibility assessments, to be promptly used for land planning policies, and is supposed to be exportable to other geological environments.

中文翻译：

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超越单一边坡定量分析：城市尺度的三维边坡稳定性评估


根据 2021 年版意大利水文地质不稳定报告，意大利很大一部分城市面临山体滑坡、洪水和/或海岸侵蚀。即使是该国的东南部地区，普利亚地区，也受到各种地质水文灾害的影响，山体滑坡集中在西北部，称为 Daunia Apennine 地区。如此重大的山体滑坡危险暴露使得需要定义可靠的定量方法来评估斜坡规模和城市规模的山体滑坡易感性，以便根据更合理的方法实施适当的土地规划政策以及有效的预防和缓解措施。本研究的主要目的是在城市地区提出一种基于物理的方法，旨在评估影响亚平宁山脉几乎所有城市地区的浅层和深层不稳定过程的滑坡易感性。所提出的方法已作为测试案例研究应用于卡兰蒂诺市 （FG），使用可用的地质和地貌图以及土壤物理和力学数据。创建了一个 2.5 km2 宽的三维岩土工程模型，包括 Carlantino 市区和城镇周围的斜坡。随后，考虑到滑移和横向的平衡条件，进行了三维极限平衡分析，以获得城市区域尺度上基于机械的安全系数图。 这项研究的结果是在与地下水位假设深度相关的三种不同情景下获得的，可以识别出更容易发生山体滑坡的区域，即以较低的安全系数值为特征的区域。与传统的 2D 稳定性计算方法相比，所提出的 3D 方法在代表性几何和地质模型的准确性方面取得了重大进步，假设该方法可以更有效地适应实际边坡条件的复杂性。此外，该方法具有重要的实际应用，因为相应的结果提供了整个城市区域的边坡稳定性条件的快速概述，可以直接用于城市规划和风险管理活动。通过与地貌证据和遥感数据的比较，这种方法已被证明是支持滑坡易发性评估的宝贵工具，可以立即用于土地规划政策，并且应该可以导出到其他地质环境。