A thermal-effect-based monitoring method for debris flow warning

Abstract

Conventional devices for monitoring debris flow have the drawbacks of short service life, unreliable data transfer, and vulnerability to severe weather in the field. Currently, passive devices using fibre optical sensing techniques have been designed for monitoring debris flow; however, they only focus on debris flow events, ignoring the detection of kinetic parameters, such as the debris flow depth. Based on the heat exchange effects between debris flows and obstacles, we developed a new method using temperature sensing to detect debris flows and their flow depth. To validate this method, we performed flume tests of a debris flow to simulate a scenario of debris flow scouring obstacles. Our results showed a debris flow can significantly reduce the temperature of measuring points within its scouring range, but it barely influences the measuring points beyond the scouring range. Therefore, the mud depth can be estimated according to the distribution of the temperature drops and cooling rates at each measuring point. The cooling rate induced by air currents is much lower than that induced by debris flow, which can be used to distinguish them in practical engineering applications.