An investigation of discharge control in landslide dam failures utilizing flexible protecting nets

Abstract

The outburst flood resulting from a landslide dam failure, commonly known as landslide dam outburst flood (LDOF), can lead to severe downstream impacts. Effective methods to prevent such catastrophic outburst floods are crucial for disaster risk reduction. This study proposes an innovative approach of using flexible protecting net (FPN) to control the outburst discharge of the landslide dam based on failure machnism. Flume experiments were conducted to investigate the effects of inflow discharges, FPN length, and the grain-size distribution of the dam on discharge control. The findings elucidated the discharge control mechanisms of the FPN and showed that: 1) the application of the FPN to the landslide dam resulted in a considerable reduction in the outburst flood hydrograph, along with a substantial decrease in peak discharge, a notable extension in the dam-break duration, and a significant increase in the residual dam height; 2) Generally, the discharge control effectiveness of the FPN improved as the inflow discharge decreased, the FPN length increased, and the mass proportion of grains exceeding the FPN aperture increased; and 3) The FPN functions by covering and obstructing dam particles, thereby, dissipating the energy of the outburst flood, finally accounting for the decrease in outburst flow. This study provides an effective method to reduce the impact of LDOF and facilitates measures for emergency disposal.