PSI - Issue 64

Lorenzo Brezzi et al. / Procedia Structural Integrity 64 (2024) 1589–1596 Author name / Structural Integrity Procedia 00 (2019) 000–000

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monitoring. In this case study, unlike past experiences, the instrumented anchors are part of a reinforcement system designed to stabilize the landslide. Therefore, unlike the previous cited experience where the anchors were studied under conditions close to the Ultimate Limit State (ULS), in this case, monitoring becomes crucial to detect the behavior under operational conditions of a stabilization system correctly sized and distributed on the landslide body. DFOSs can offer insights into the adequacy of anchor design, its effectiveness in remediation, and its health over time. Secondly, they enable anchors to function as sensors themselves, facilitating the monitoring and characterization of landslide movements and geometry. The article delineates the system and provide detailed installation procedures. Additionally, preliminary results obtained during the few months of measurement campaign are presented.

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Fig. 1. Passive anchors installation method.

2. The case study of Paradisi landslide (BL, Italy) 2.1. Paradisi landslide (BL, Italy)

Paradisi landslide is located in the municipality of Ponte nelle Alpi, in the province of Belluno, North Italy (Fig. 2). The landslide is characterized by a complex movement: at the head of the landslide, the movement is considered rotational between the moraine debris cover and the Belluno flysch, while, at the toe, the phenomenon is characterized by lobes of detachment spreading halfway down the slope. The rainfall events, combined with water input from a stream located at the center of the affected area, the Rio San Pietro, which in turn feeds the landslide and generates high-speed mudflows, decreased the stability of the slope, so from 2014 the first movements started to manifest themselves. Being composed of very poor resistance material, this led to the displacement of a large volume of soil estimated at around 150’000 – 200’000 cubic meters, an average width of 115 meters, a length along the maximum slope line of 200 meters, and an estimated thickness of 6-8 meters. Prior to the intervention (Fig 2b) the velocity of movement was estimated to be a few centimeters per day, leading to the formation of a distinct and visible fracture line upstream. The movement persisted steadily from the onset of the phenomenon until the initial intervention phase, which involved geometric profiling (2022) and the installation of drainage trenches (Fig. 2c), resulting in a deceleration of the body's movements. Refining the geological-technical model and enabling the application of the Observational Method through newly installed traditional instruments (inclinometers and piezometers), a second phase of interventions has been designed. This phase involves the application of structural forces using innovative technologies that can be gradually implemented and continuously monitored. The structural objective is to absorb horizontal stresses and reduce the solicitations inducing landslide movements, while also requiring an assessment of