Experimental Investigation on the Breaching Process of Landslide Dams with Differing Materials under Different Inflow Conditions

Abstract

Landslide dams are dangerous because the outburst floods produced by dam failures seriously threaten life and property downstream. In this study, a series of physical flume tests were conducted to investigate the breaching process of landslide dams with fine-grained, well graded, and coarse-grained material under different inflow conditions. The effects of dam material and inflow discharge on the breach development, outflow discharge and erosion characteristics were studied. The erosion resistance of materials and lateral collapses were also discussed. Experimental results reveal that the whole breaching process is determined by the water-sediment interaction. For the fine-grained dams, a general constant downstream slope angle is maintained during the breaching process. For the well-graded dams, a step-pool structure is generated due to the scarp erosion. For the coarse-grained dams, they can remain stable under normal circumstances but fail by overtopping in a short duration under the extreme inflow condition. The final breach of the dam with higher fine content or larger inflow discharge is deeper and narrower. In addition, many fluctuations are observed in the changing curve of the erosion rates along the flow direction for the well-graded and coarse-grained dams. The erosion resistance of materials increases along the flow direction, which needs to be further considered in physically based breach models. Furthermore, the lateral collapse is affected by the dam material instead of inflow discharge. The lower fine content causes more lateral collapses with smaller volumes.

Breach Progression Observation in Rockfill Dam Models Using Photogrammetry

“…This is also touched upon in several other publications such as [10,11]. There is also available research on landslide dams [12][13][14] as well as glacial moraine dams [15] that have looked at more well-graded materials. One research project of particular interest is the IMPACT project, where a series of large-scale tests were conducted on various rockfill, moraine and clay dams [11,16].…”

Special Issue: Advancement of Functionalized Mineral Materials and Rock

“…The physical and mechanical behaviour, fracture, damage, and evolution processes of geomaterials under various environmental and mechanical conditions, such as thermal, mechanical, chemical, and electrical environments [6][7][8][9][10][11][12][13][14][15][16][17]20,21].…”

“…This Special Issue covers numerous aspects of functional mineral research. These topics focus on various themes, including the analysis of mineralogical composition and its effects on the physico-mechanical properties of geomaterials, the investigation of the impact of triaxial stress on the damage creep behaviour of geomaterials, and the evaluation of the thermophysical and mechanical characteristics of rocks under high-temperature circumstances [6][7][8][9][10][11][12][13][14]. The research conducted on these topics also involves various experimental and numerical techniques, such as digital image processing, Discrete Element Method (DEM), and analytical solution and simulation [13,[15][16][17][18].…”

“…Shi et al [10] conducted an investigation on the breaching process of landslip dams using physical flume tests. The study took into account the impact of different grain compositions and inflow conditions.…”