Experimental investigation of blocking and discharge regulation function of window-frame dam in viscous debris flow control

The blocking of a window-frame dam and the discharge regulation are both important basic control features for characterizing the regulatory effect of a window-frame dam on debris flow. To better understand the regulatory effect of a window-frame dam on debris flow, physical model tests were carried out to investigate the flow pattern, trapping, and regulating characteristics when debris flow passed through a window-frame dam. The results revealed that the opening size of the dam and bulk density of the debris flow were the main factors affecting the blocking degree of the dam, followed by flume gradient. And a new comprehensive criterion for the blocking degree is proposed considering the multiple factors. Window-frame dams can regulate the discharge of debris flow to a certain extent under different conditions, and the control effect of discharge of viscous debris flow is not only reflected on the reduction of peak discharge, but also on the delayed effect of viscous debris flow. Moreover, the reduction rate of the peak discharge of debris flow is related to the blocking degree of the dam, which implies that designers should consider more factors in the determining the opening parameters of window-frame dams.