The Features And The Initiated Mechanism Of The Typical Mine Debris Flows In Guizhou Province

Mine debris flow belongs to the research field of debris flow, with the unceasingenhancement of economic activities, people request the over-consumption of naturalresources and sustained damage to the environment, these make the mine debris flowmore serious,. once the mine debris flow breakout, the damage will be enormous.Therefore, the study of features and the initiated mechanism of the typical mine debrisflows in Guizhou province is very necessary, it can provide some theoretical basis forearly warning and forecasting for the mine debris flow.By field investigation and data collection on5typical mine debris flow gully inthe study area, this article analysised the features and initiated mechanism of the minedebris flow, get the following conclusion:(1) The study area located in the Zhongshan district of Liupanshui in Guizhouprovince, there are five typical mine debris flow gullies in this area, these mine debrisflow gullies are all triggered by rainfall, as a lot of mining deposit piles up in valley,this may lead to produce mine debris flow. The distribution of mine debris flow isinfluenced by the distribution of mineral resources in the study area. With thesostenuto mining, the quantities of mine debris flow will be more and more, thesetypical gully basins are generally small in size, and concentrated, the main river haslittle influence on the characteristic of the distribution.(2)The landscape of the study area is mountain and mountain landforms, exposedbedrock is limestone, basalt, sand, shale and so on, the slope of the five mine debrisflow is usually an average of151-276‰. Bank slope is greater than30°. The basinsare all less than0.5km2.The gully is straight. The vegetation cover in general, and it isdominated by grasses and shrubs, these provide terrain conditions for the formation ofdebris flow.(3) the main material source of the mine debris flow is the mining deposit, it isconcentration, its surface is loose and bare, deposit provenance and the volumeaverage of150000-500000m3, and the mining deposit is glowing, it is easy to erosionby rainfall runoff scour. (4) Rainfall is the trigger of the outbreak of the mine debris flow, annual rainfallis concentrated, and there is most rainstorm. These conditions make the mine debrisflow gullies easy to outbreak of debris flow disaster.(5) By the calculation of the mine debris flow in the area, the density of the minedebris flow is1.56-1.72t/m3, under the condition of the worst storm in50years, thepeak flow of2.81to2.81m3/s, debris flow is6.71to6.71m3/s, debris flow volumeis4800-114000m3, runout of the total solid is0.17-0.39m3/s. Under the condition ofthe worst rain in100years, the peak flow is3.08to3.08m3/s, debris flow is7.33-7.33m3/s, debris flow volume is5300-12500m3, the total runout solid is0.190.52m3/s. All the typical mine debris flow is low risk.(6) According to the Moore-coulomb failure criteria and adopt the method oflimit equilibrium, analysised the mine debris flow in the critical starting condition, thecritical starting model is set up.The starting runoff depth of water and slag deposit thickness were positivelycorrelated, the starting runoff depth of water and the slope of the gully bed showed anegative correlation relationship, and this model is suitable for less than21°slope.