Research On The Formation Mechanism And Prevention Measures Of Debris Flow In Weila Dam, Lushui County

Daxing town Vera dam debris flow located in the Wanglaluo basin which belongs to the Nu river tributary in Lushui country,Yunnan province.Because of the special geographical location and geological conditions,this debris have strong activity and have a great damage,threatening to thousands life live in downstream region.Based on the investigation and study of the debris flow,the formation mechanism of the debris flow is analyzed,and the corresponding prevention and control measures are put forward.The results provide a scientific basis for debris flow disaster control.The following research results and understandings are obtained:(1)Vera dam debris flow from rainstorm in cheuch,which belongs diluted,low frequency debris flow,the level is lager-scale,and the level of prevent projection is second.(2)Debris flow gully was beneficial to the occurance of debris flow as prosess the landforms and stratigraphic lithology conditions.The main ditch source were erosion of slope and rill,accumulation of gully bed,and gravity erosion,of which gravity erosion have the highest propotion,the second was erosion of slope and rill.In addition,the larger precipitation and good water resource provided the driver for the formation of debris flow.(3)By field investigation and inside analysis,we acquisited the type of solid loose materials,annual maximum miving dimension,the stone diameter of avalibale,the overall impact force,and roke impact force.Then calculated the flux and flow velocity of debris flow,and provide the basis design consideration of the prevention debris flow.(4)Results showed that the more suitable design scheme was valley prevention dam + Dongchuan slot + solid bed rib engineering.It is suggested that should bulid 3valley dam,beam barrier 30 m,Dongchuan slot 878.5m,44 solid bed rib,6 draw step,3 auxiliary bridge,approach channel 63 m.(5)Our research illustrated that adopt the thoughts of check dam,raise the erosion base,project in back pressure valley slope,in certain times,debris flow willcontrolled and improve the lithology conditions of debris flow gully.