GNGTS 2019 - Atti del 38° Convegno Nazionale

GNGTS 2019 S essione 2.2 355 Advanced tools: a first step. More accurate and advanced approaches of seismic vulnerability assessment are currently being developed. The main objective of this work is to define pseudo-empirical rules for seismic vulnerability assessment applicable to all small earth dams of the French-Italian Alps. In this regards, statistical analyses of numerical model results are ongoing. Numerical analyses consist of dynamic simulations by using finite difference commercial software FLAC ® . A set of 10 real accelerograms recorded at rock outcropping sites for the return period of 475 years has been selected on the basis of French-Italy Alps seismic hazard. One of the main problems in the development of this approach has been the construction of numerical models of dams, due to the lack of knowledge on soil characteristics. Indeed, many of these dams generally have been built with limited technologies and economic means, compacting local natural materials. Therefore, the body of dam is often heterogeneous with a wide variety of soils (from clay to rock blocks). In this respect, a geophysical and geotechnical characterisation campaign was performed. Four small earth dams were selected on the basis of seismic vulnerability results obtained from the simplified approach described above. Geophysical tests were based on surface wave methods (MASW, H/V), down-hole tests and geoelectric tests. Geotechnical investigations included in situ tests (CTPu with seismic cone, and DMT), and static and dynamic laboratory tests conducted on undisturbed samples. Fig. 2a shows the V S profile of Arignano dam obtained by surface wave methods. Based on the site investigation, a numerical model of this dam (Fig. 2b) was built. The geotechnical parameters adopted for each layer of the model are reported in Tab. 2. Fig. 2 - (a) Shear wave velocity models: lower misfit solution (red line); (b) FLAC ® numerical model of Arignano dam.