Monitoring soil-water and displacement conditions leading to landslide occurrence in partially saturated clays
Monitoring soil-water and displacement conditions leading to landslide occurrence in partially saturated clays
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DOI：
10.1016/j.geomorph.2012.06.006
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发表时间：
2012-11
期刊：
影响因子：
3.9
通讯作者：
M. Bittelli;R. Valentino;F. Salvatorelli;P. Pisa
中科院分区：
文献类型：
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作者：
M. Bittelli;R. Valentino;F. Salvatorelli;P. Pisa
浅层滑坡经常发生在短暂降雨入渗和部分饱和条件下。然而，对触发它们的原因的详细分析，特别是在粘土中，往往因缺乏现场测量而受到阻碍。事实上，在装有仪器的自然斜坡上捕捉到它们的出现并不常见。本文介绍了一项综合现场实验的结果，该实验监测了导致部分饱和粘土中发生浅层滑坡的土壤-水和位移条件。各种实验技术的整合可以检查土壤水文和机械特性之间的相互作用。这项研究还评估了基于吸应力概念的边坡稳定性模型。由于该模型是在滑坡发生后应用的，因此结果被解释为模型评估的后铸技术。尽管如此，监测活动期间获得的详细现场测量结果以及实验期间滑坡的发生为模型参数和数据解释提供了重要信息。该站提供天气变量、土壤含水量和土壤吸力数据的远程卫星监测。垂直安装时域反射电缆以检测潜在的土壤破坏。试验区发生滑坡的概率较高。观测期间确实发生了斜坡崩塌，显示了该站对滑坡发生情况、时间和深度的探测效果。滑坡是由于吸力变化而引发的。破坏面发生在 1.4m 的深度，对应于 1 至 1.45m 厚的较高渗透性表面层与具有较低渗透性的压实基底之间的界面。该分析可以测试模型的有效性，并描述在非饱和条件下观察到的浅层滑坡的触发机制，表明土壤基质吸力的振荡是决定土壤破坏的主要变量。
Shallow landslides frequently occur during transient rainfall infiltration and under partially saturated conditions. However, a detailed analysis of what triggers them, particularly in clayey soils, is often hindered by the lack of field measurements. It is uncommon, in fact, to capture their occurrence in an instrumented natural slope. This paper presents results from an integrated field experiment monitoring the soil-water and displacement conditions that lead to the occurrence of a shallow landslide in partially saturated clays. The integration of a variety of experimental techniques allowed for the examination of interplay between soil hydrological and mechanical properties. This research also evaluates a slope stability model based on the suction stress concept. Since the model was applied after the occurrence of the landslide, the results are interpreted as a hind-casting technique for model evaluation. Nevertheless, the detailed field measurements acquired during the monitoring activity and the occurrence of a landslide during the experiment provided significant information on model parameters and data interpretation. The station provides remote satellite monitoring of data on weather variables, soil water content and soil suction. A time domain reflectometry cable was installed vertically to detect potential soil failure. The experimental area had a high probability of landslide occurrence. Indeed, slope failure occurred during the observation period, showing the effectiveness of the station in detecting the occurrence, time and depth of landslides. The landslide was triggered in consequence of changes in suction stress. The failure plane occurred at a depth of 1.4m, corresponding to the interface between a superficial layer of higher permeability of 1 to 1.45m thickness, slipping over a compacted substrate having lower permeability. The analysis allowed for testing of the validity of the model and the description of the triggering mechanisms of the observed shallow landslide in unsaturated conditions, indicating that oscillations in soil matric suction were the dominant variables determining soil failure.