官坝河泥石流动力学特征参数

Dynamics Parameters of Debris Flows in Guanba River

青藏高原东南缘构造断陷湖都不同程度地受到山洪和泥石流侵蚀带来的泥沙淤积的影响。其中邛海的泥沙淤积问题最具代表性。邛海日益严峻的泥沙淤积问题的解决取决于流域内山洪和泥石流的治理。在此背景下,分析了邛海流域官坝河地形地貌特点和邛海泥沙淤积特征,并计算了官坝河泥石流动力学特征参数。研究发现,官坝河流域泥石流属于过渡性—黏性泥石流,1998年官坝河泥石流最大洪峰流量为813.7m3/s,泥石流最大动压力和大石块冲击力分别为147kPa和1.63×105 kN。据此提出了邛海流域官坝河泥石流防治建议:在官坝河上游支沟采用稳拦防治措施以稳固沟床和拦挡大颗粒物质;在官坝河下游采用拦排清防治措施以减少细颗粒物质进入邛海并定时清理河床泥沙。邛海流域官坝河泥石流的治理可为青藏高原东南缘构造断陷湖区域内的山洪和泥石流治理提供一定的参考价值。

The fault lakes around belt of southeast Tibet were influenced by the sediment deposition coming from the erosion of flash flood and debris flows, in which the example was Qionghai. But the problem that sediment severely deposited in Qionghai relied on the prevention and control of flashflood and debris flows. Under this background, the topography of Qionghai drainage and the character of sediment deposition were analyzed, and the dynamics parameters of debris flows were calculated. The debris flows of Guanba river was trasitional viscous. The peak discharge of debris flows was 813.7 m^3/s, and the highest dynamic pressure and impact force of massive stone was 147 kPa, 1. 63× 10^5 kN, respectively. Above of all, the prevention and control for debris flows was made. Stabilizing slopes of gully and blocking large particles in higher reaches area of Guanba river, reducing fine particles and desihing sediment in lower reaches area of Guanba river should be practiced. This work was useful for prevention and control of debris flows in other fault lakes around belt of southeast Tibet.