Cascade Effect Analysis in Torrential Context for Prioritizing Check Dams Maintenance Strategies

International audienceNatural hazards in mountains pose threat to people, properties, and infrastructures. Several mitigation strategies aim to reduce the induced risk and to protect vulnerable issues exposed to such dangerous phenomena. Check dams are one type of structural protection measures constructed in series along mountain streams. They constitute a critical interdependent multi-component system that deteriorates over time and requires regular inspection and maintenance. The propagation of damage is influenced by failure dependencies existing within a single dam and/or between multiple dams. Such cascading events reduce the efficacy of the overall system in providing protection. Due to limited budgetary resources, it is essential to identify the most critical structures involved within the system and to capture the state of degradation at which preventive maintenance should be carried out. Consequently, performing a dependability analysis of such systems is highly important. This requires analyzing the dynamic deterioration of each dam and the local or distant effects of its partial or total unavailability on other consecutive dams. The present study integrates physical numerical models analyzing the dynamic state evolution of check dams while being subjected to a series of torrential flood events over a specified period of time with stochastic Petri nets modeling the maintenance processes. The developed models are applied on a simple protection system composed of two check dams. The results achieved permit analyzing the behavior of one dam in the presence or the absence of the other dam and prioritizing several proposed maintenance strategies taking into consideration economic constraints