尖山包沟泥石流成因及动力学特性研究

Study on causes and dynamic characteristics of debris flow in Jianshanbao Ravine area

尖山包沟区域极端气温差为40.6℃、极端地温差为77.7℃,沟域所在地区多年平均降雨量为1058 mm,24h降雨强度可达111.5 mm。流域沟内地层岩性以软质—极软质岩为主,流域内松散固体物质总量约2.0×10~7m^3;沟内相对高差达1328 m,沟床平均坡降为132.21‰;尖山包沟泥石流的爆发因素主要是丰富的固体物源、丰沛的降雨和暴雨降雨强度、陡峭的地形等。在高强度暴雨的作用下,聚集的洪水裹挟着松散固体物质沿陡峭的山沟快速向下流动而形成泥石流;泥石流流速为4.77 m/s,整体冲压力为3.71 k Pa,泥石流最大冲起高度为1.16 m,受阻爬高可达1.85 m。

In Jianshabao ravine area, the extreme temperature difference ranges 40. 6℃ and the extreme ground temperature difference ranges 77.7℃.The average annual precipitation is 1058 mm and the twenty-four hours rainfall intensity can be up to 111.5mm.The stratum lithology mainly are soft rocks and very soft rocks, and the total amount of loose solid matter is about 2.0× 10^7m3. The relative height difference in the ravineis up to 1328 m and its average gradient of ditch bed is 132. 21‰. The main factors causing the Jianshanbao ravine debris flow are rich solids source, abundant rainfall, storm rainfall intensity and steep terrain. Under the action of high intensity rainstorm, the flood carries the loose solid material and rapidly flow down along the steep ravine and form debris flow. The velocity of debris flow is 4. 77 m/s, its overall pressforce is 3.71 kPa. The maximum height of debris flow is 1.16 m and it can climb up to 1.85 m when it is blocked.