A Check-Dam to Measure Debris Flow-Structure Interactions in the Gadria Torrent

Abstract

To design technical mitigation structure against debris flows in torrents it is important to define realistic design impact loads. Presented impact forces were mostly derived from back calculations of past events and yielded a rough estimation. The majority of scientific publications of impact force are based on small scale experiments in laboratories, but the transfer to real scale problems is limited due to scaling issues. Monitoring in real scale of debris flows is necessary to understand the process and the apparent phenomena. The Gadria valley in the Autonomous Province of Bozen-Bolzano is one of the rare areas were debris flows frequently occur. Therefore the Gadria torrent is already equipped with a monitoring station to provide data to analyze the occurring debris flows. To measure real scale impact forces of a debris flow and the variables that are necessary to calculate and understand the impact process and the debris flow/structure/ground interaction, a special monitoring check dam is designed and will be built in September 2016. An arrangement of 38 sensors will measure the impact forces on the check dam, the acceleration of the construction and the interaction with the ground. Also the pore water pressures, weights and heights of the debris flows will be recorded. This arrangement of sensors should help to understand the debris flow structure interaction to facilitate the calibration of numerical models and to improve guidelines for national standards.