Assessing the stability of a complex landslide through geotechnical modelling

Two adjacent landslides affect the National Road 52 "Carnica" in the Tagliamento River valley, Carnian Alps (46°23'49" N, 12°42'51" E). The phenomena have been studied for more than a decade allowing a detailed geological and geomorphological reconstruction to be delineated. That was done on the ground of a large number of monitoring data collected during more than 10 years of investigations. Since the landslide are threatening an important road countermeasure works to ameliorate stability conditions of the slides need to be designed. The paper focuses on the creation of a numerical model capable to reconstruct the dynamic of both landslides and to be consistent with monitoring data. Two cross-sections, one for each landslide, have been selected for the analysis. The geometry of the slip surface was reconstructed on the basis of control points like the slip surface readings in inclinometers and on geomorphological evidence for the contour. The FLAC2D code is used to evaluate actual stability of these landslide. Results will be used to plan countermeasure works.