Dynamic response of dilute to viscous channelized debris flow on pipeline crossing

This study experimentally investigates the dynamic response of dilute to viscous channelized debris flows on pipeline crossing. The debris flow impact mechanism, front flow depths, and front velocities were measured and analyzed using pressure transducers, ultrasonic sensor, and high-speed cameras in a 9-degree inclined flume at different solid volume fractions (αs). The debris flow samples were characterized as dilute to viscous mixtures based on calculated Froude and Reynolds numbers. The experimental findings revealed that dilute debris flows impacted the pipe model in turbulent manner with splashing phenomena. In contrast, viscous debris flows exhibited relatively less flow velocities, leading to the layered impact phenomena. Significant variations in flow depths, frontal velocity, and impact pressures were observed due to composition and flow mechanism of debris flow mixtures. Front flow depths were substantially increased, while front velocities and impact pressures were decreased with an increment of solid volume fractions. The calculated dimensionless number confirmed the similarity of experimental results with those observed in natural phenomena and other experimental studies. Further, for dilute debris flows, dimensionless impact pressure was a power function of Froude number (Fr), while for viscous debris flows, it was a power function of both Froude number (Fr) and Reynolds number (Re).