Research On Development Characteristics And Control Measures Of Wuhuhai Debris Flow In Jiuzhaigou Scenic Spot Grade

This thesis takes the Wuhuahai debris flow in Jiuzhaigou scenic area of Jiuzhaigou County as the research object.Firstly,the debris flow data and related literature at home and abroad are collected and read,then the debris flow is divided into formation area,material source area and accumulation area by investigating the geological environment conditions of the debris flow,finally the formation mechanism and development trend of the debris flow are analyzed.Then,according to the relevant specifications,the movement characteristic parameters of Wuhuahai debris flow,such as gravity,velocity,discharge and impact force,are calculated and analyzed,and an economic and reasonable engineering prevention and control measures is proposed.The main conclusions are as follows:(1)The Wuhuahai debris flow has fewer branches and the ditch are shaped like oak leaves.The area of the debris flow is 2.65km~2,the length of the main ditch is about 3.5km,the average width is about 0.9km,the longitudinal ratio of the main ditch is reduced to435‰,the slope is relatively steep,and the hydrodynamic conditions are good.According to the preliminary statistics of the survey,the total amount of collapsed solid sources is12.9×10~4m~3;the total amount of solid sources deposited in trenches is 1.1×10~4m~3;the total amount of solid sources of slope erosion is 1.1×10~4m~3,the total amount of loose solid sources is 15.1×10~4m~3,the amount of sources that can participate in the movement of debris flow is 1.88×10~4m~3.(2)The Wuhuahai debris flow gully is rich in material sources.If a large-scale debris flow disaster occurs again,it will seriously threaten the safety of roads,pedestrians and vehicles in the scenic area.The potential risk grade of debris flow is small,and the threat object is grade three.(3)Wuhuahai debris flow belongs to rainstorm,gully type,low frequency,rarefied debris flow,and its development stage belongs to development period.According to field surveys and calculations,the volume density of debris flow in Wuhuahai is 1.49t/m~3,the peak flow rate is 14.99m~3/s,the flow rate is 5.68m/s,the total amount of debris flow is0.92×10~4m~3,and the outflow of solid matter is 0.35×10~4m~3.(4)The protection objects of the Wuhuahai debris flow are the tourists and the landscap in the accumulation area.In consideration of the siltation of Wuhuahai caused by the washed out debris flow and the damage to the water quality landscape and vegetation in the gully area,it is necessary to minimize the start of debris flow and intercept the debris flow in the gully area.Therefore,the treatment project adopts the general idea of"blocking solid and stopping,supplemented by water filtering and greening engineering".