不同条件下泥石流堰塞坝的溃决过程

目的]对不同因素作用下的泥石流堰塞坝溃决过程进行试验研究,为泥石流堰塞坝的灾害防治和灾后重建等提供科学支撑。方法]开展了不同来水流量、坝体形态、黏粒含量、坝高和初始含水量条件下的溃决试验。将漫顶溃决过程分为4个阶段:坡面侵蚀过程、陡坎侵蚀过程、下切和侧向侵蚀过程和衰退过程。此外,分析了泥石流堰塞坝坝体破坏机理,并给出下游坡面泥沙起动临界条件的计算式。结果]溃决流量与来水流量之间呈非线性正相关;溃决洪峰流量随着背水坡坡度增加而增加;溃决洪峰流量随着坝高的增加而迅速增加,泥石流堰塞坝坝体黏粒含量与溃决洪峰流量之间整体呈现负相关;溃决洪峰流量随着土体初始含水量的增加而缓慢降低,但变化的范围不大。结论]在泥石流堰塞坝溃决的不同因素中,坝高和黏粒含量影响最大,来水流量次之,背水坡度和初始含水量影响最小。

Process of Debris Flow Dam Break Under Different Conditons

Objective] To provide scientific support for the disaster prevention and reconstruction of debris flow dams, an experimental study on the process of debris flow dam break under different factors was conducted.Methods] Dam failure tests were carried out under different inflows, dam shapes, clay contents, dam heights, and initial water contents. The breaking process was divided into four stages:slope surface erosion process, scarp erosion process, lateral erosion process, and decline. The failure mechanism of the debris flow dam was analyzed, and the formula for calculating the critical opening condition for the downstream slope sediment was obtained.Results] There was a nonlinear positive correlation between the outburst discharge and the inflow water flow. The peak discharge of the outburst increased with the slope degree of the backwater slope. The outburst peak discharge increased rapidly with the increase in the height of the dam, and there was a negative correlation between the clay content and the outburst flow. The peak discharge of the outburst flow decreased slowly with the increase in the initial water content of the soil, but the range of variation was not large.Conclusion] Among the different factors of debris flow dam break, dam height and clay content have the greatest influence, followed by incoming water flow, backwater slope and initial water content have the least influence.