Development and preliminary tests of a low-power automatic monitoring system for flexible debris flow barriers.

Debris flows are a type of mass movement characterized by high velocities and rapid evolution over time. These features, together with their capability to transport huge amounts of material, make them one of the most hazardous natural processes for both human lives and man-made structures. Therefore, a timely and effective monitoring activity plays a major role in any mitigation and early warning action connected with debris flow, such as alert messages dissemination and road closures. This paper deals with the development of a new automatic system named Gflow Safety Network (GSN), designed to be installed on flexible debris flow barriers with the objective to monitor the structure behavior with a real time approach. The main component of the system (called Gflow module) integrates an accelerometer and an electronic board, and it is able to identify an impact that generates an acceleration value higher than a predefined threshold. In this scenario, the system activates the accelerometer sensor integrated in the module and triggers every other monitoring device installed on-site to acquire information on the ongoing phenomenon. A series of impact tests were performed on a prototype installed on a flexible structure, in order to verify the initialization time of the accelerometer sensor after the first threshold overcoming. The outcomes evidenced the good performances of the Gflow module, which was able to record the event following the first impact on the test structure.