基于FLO-2D模型的泥石流治理工程效益评价

Benefit Evaluation of Debris Flow Control Engineering Based on the FLO-2D Model

泥湾沟为白龙江一级支沟,沟内地质构造发育,固体松散物质丰富,历史上曾爆发多次大规模泥石流灾害,属典型暴雨型黏性泥石流。为更好的对该工程效益进行评价,本次采用FLO-2D模型对其治理前后不同频率的泥石流运动、堆积情况及危险性进行模拟对比。研究结果表明,防治工程的布设能有效拦截流域内松散物质,拦截方量约为3.97×10^4m^3,回淤反压稳固坡体效果更加明显;泥石流流速控制作用明显,1%降雨频率下到达沟口处流速为2.7m/s,且呈沿拦挡工程逐级减小的趋势。在松散物质及流速得到有效控制的情况下,泥石流冲出方量减少,堆积范围缩小,缩小比例最大达84%。该方法不仅有利于评价泥石流治理效益,也对泥石流治理方案的提出提供有效的数据支持,是值得借鉴与参考的一种评价方法。

The Niwangou ditch is the first tributary of Bailong River, where the geological structures are very developed and the loose materials are abundant. In history, there happened several large-scale debris flow disasters, which belong to typical rainstorm viscous debris flow. For the better benefit evaluation of debris flow control engineering, the FLO-2D model has been applied to simulate and compare the debris flow movement, accumulation, and risk under different frequency before and after the treatment. The results show that the loose material originally accumulated at the exit of gully will be intercepted in the dam body with the volume of 3.97×10^4 m^3 by the control engineering. Moreover, the flow velocity of debris flow can be effectively controlled, and the maximum flow velocity at the exit of gully is 2.7m/s when the rainfall frequency is 1%. And this engineering will limit the accumulation range of debris flow, the reduction ratio can be greater than 84%. The method is not only to the benefit of evaluation of debris flow control engineering, it also provides the effective data support to the treatment scheme. Overall, the evaluation method is a worth reference by researchers.