| Shawan Big Groove debris flow is located in the middle reaches of the block river,belonging to the xiaojiang river basin of the jinsha river system of the Yangtze river basin.Due to its special geographical location and geological conditions,it is highly active and threatens the safety of life and property of more than 1,000 people downstream.The investigation and study of the debris flow can provide solid foundation and practical experience for the subsequent debris flow disaster management.Through the investigation of indoor and outdoor environment,the following conclusions are drawn:(1)Sha Wan Big Groove debris flow is gully rainstorm viscous high frequency debris flow,and the grade is extremely large.(2)debris flow gullies have topographic,geomorphological and stratigraphic conditions conducive to debris flow.The material sources in the gullies mainly include slope and rill erosion,gully deposit and gravity erosion,of which the proportion of gravity erosion is the highest,followed by slope and rill erosion.In addition,there is a lot of precipitation in the area,and the water source conditions are good,which provides the dynamic conditions for the formation of debris flow.(3)through indoor and outdoor investigation and analysis,parameters such as the solid loose matter type of debris flow channel,the maximum annual moving amount,the diameter of movable boulders,the overall impact force of debris flow and the impact force of boulders were obtained.The calculation results of flow rate and velocity of debris flow are obtained,which provides a basis for the prevention and control of debris flow.(4)through the analysis and research of the first-stage governance project,namely the combination of the open dam and the second stage superimposed dam,the problem of thick overburden layer at the dam foundation position in the debris flow gully is solved,which cannot meet the requirement of bearing capacity,and the problem of the impact of high potential erosion on the dam foundation after the dam is solved.(5)through the analysis and evaluation and research of the governance effect of the first stage project,the feasibility of the second stage project is analyzed,that is,the diversion channel is adopted to strengthen the dam structure,to ensure the safety of the first stage project built,to solve the problem of scouring by high potential debris flow on the dark dam built,and to lay a foundation for the construction of multi-stage overlays.(6)the theoretical and practical feasibility of multi-stage superimposed dam is found through the first and second stage engineering practice and theoretical research,which provides a possible design idea and solution for debris flow disaster management project. |
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