Experimental study on the breaching process of landslide dams with different particle contents
[Objective]Landslide dams are usually with loose structure and wide range of particle gradation and prone to overtop-ping failure,which seriously threatens the life and property safety of up and downstream people.In order to further understand the breaching process of landslide dams under the condition of different particle contents within the same particle size range,[Methods]several breaching tests models by flume were carried out by using the"11.3"Baige landslide at Jinshajiang River as a reference prototype.[Results]The result show that the failure process of landslide dams can be divided into four stages,inclu-ding seepage and overflow,backwater erosion,breach development and attenuation equilibrium.Both the rate and discharge of the breach flow first increase and then decrease with time,but the peak flow rate lags behind the peak flow rate.In addition,the impact force of the flow increases continually in the stage of breach development and begins to decrease in the stage of attenuation equilibrium,while the flow severity shows a certain range of fluctuation in the stage of breach development.With the increase of the median particle size,the rate of breaching peak flow decreases,the appearance time of peak flow delays,the peak of the impact force of the breaching flow decreases,and the length of the sediment deposition downstream becomes shorter and the area larger.[Conclusion]This paper further reveals the influence of different particle contents within the same particle size range on landslide dam stability,breaching process and parameters,which would likely contribute to risk assessment and emergency response.
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