Experimental Study On The Collapse Mode Of The Dam And Its Dam Failure Evolution Characteristics

China's mineral resources are rich,and its geological structure is complex.Especially in the areas where mineral resources have been exploited for many years,the natural environment is fragile.Under the action of human activities and natural transformation,a large number of loose accumulations are formed in the natural channel,causing the channel.Partially blocked or completely blocked.Under the action of long-term upstream runoff,a small number of blocked bodies are taken away,and most of them accumulate in the channel to form natural dams.The upstream flow continuously gathers upstream of the dam to form a dammed lake similar to a small reservoir.As the reservoir water level rises and the dam body oscillates,the dam body is prone to dam break,which in turn forms a destructive debris flow.The time period of the debris-type debris flow disaster,the large scale of disasters,and the strong destruction ability pose great threat to the safety of human life and property.In order to further understand the failure mode and characteristics of the dam,this paper carries out model tests,which is of great significance for the prevention of dam breach.There are many factors affecting the collapse of the dam.This paper is based on the research that has been carried out by the predecessors.Based on the dams in the two main channels of the Xiaoqinling gold deposit,the field investigation and feature analysis and sampling are based on the indoor model test.Based on the theoretical analysis,the influence of the particle ratio of the dam material on the collapse mode of the dam is extremely studied.The evolution of the debris flow is obtained.The following results have been achieved:(1)The mining activities in the Xiaoqinling gold mining area are strong,which has caused great changes to the surface structure.The mining area has high altitude,steep terrain and low vegetation coverage.There are abundant rainfall in summer and autumn,and there are a lot of mining wastes in the channel and bank slope.History There have been many major debris flow disasters,and there are many blocked and semi-blocked natural dams in the channel,which provide conditions for the dam-breaking debris flow.(2)Through the dam failure test under six working conditions,it is found that there are two modes of dam failure:the flooding dam and the“like landslide”type dam break.There are two manifestations of the flood dam break,one is overflow.Erosion type,the other is"overflow erosion + piping" type.(3)Overflow erosion dam break is the most common form of dam breakout.The development mechanism is the process of formation,deepening and expansion of the crater:the traction force of the dam water flow forms a breach;the dam water flow washes the longitudinal depth of the rupture;the collapse of the collapsed port slope Scale the breach horizontally.(4)There are three stages in the severity and velocity of the dam-breaking debris flow.The failure mode of the dam-dam is very significant for the dam-breaking debris flow,and the dam-breaking mode is closely related to the fine-grain content in the dam.(5)During the collapse of the dam,the internal moisture content,pore water pressure and earth pressure of the dam are constantly changing.Under different dam failure modes,there are obvious differences.The "overflow erosion + piping" type dam has the largest scale and the most destructive.