Measuring internal velocity of debris flows by temporally correlated shear forces

Debris flow is a kind of geological hazard occurring in mountain areas. Its velocity is very important for debris flow dynamics research and designing debris flow control works. However, most of past researches focused on surface velocity and mean velocity of debris flow, while few researches involve its internal velocity because there is no available method for measuring the internal velocity for its destructive power. In this paper, a method of temporally correlated shear forces (TCSF) for measuring the internal velocity of debris flows is proposed. The principle of this method is to calculate the internal velocity of a debris flow using the distance between two detecting sections and the time difference between the two waveforms of shear forces measured at both sections. This measuring method has been tested in 14 lab-based flume experiments.