汶川县映秀镇牛圈沟溃坝型泥石流起动临界条件初步分析

为预测牛圈沟潜在溃决点失稳后引发泥石流灾害规模,对牛圈沟3个堵溃点溃决流量进行了预测,计算了溃决洪水影响距离及到达时间,提出了针对牛圈沟堵溃型泥石流起动的判别公式,最后分析了泥石流可能造成的危害。其中得到溃决流量过程曲线,1#、2#堵溃点峰值流量值分别为1124.6m3/s、495.6m3/s,3#堵溃点主要发生沟道侵蚀,并不产生大规模溃决破坏。三个堵溃点溃决后洪水流量放大效应影响距离及到达时间进行了计算,1#堵溃点影响范围到达下游堆积区,2#堵溃点影响距离为547m。牛圈沟溃决型泥石流规模将远大于无溃决泥石流的规模。

In order to predict the scale of debris flow disaster caused by the instability of the potential outburst point in niuquan gully, the flow flow of the three outburst points in niuquan gully is predicted, the impact distance and arrival time of the outburst flood are calculated, and the discriminating formula for starting of the type of debris flow in niuquan gully is put forward, and the possible harm caused by the debris flow is analyzed. The process curve of outburst flow is obtained. The peak flow values of # 1 and # 2 are 1124.6m3/s and 495.6m3/s, respectively. The influencing distance and arrival time of flood flow amplification effect were calculated after three outburst points. The influencing range of 1# breach point reached the downstream accumulation area, and the influencing distance of 2# breach point was 547m. The scale of niuquan gully outburst debris flow will be much larger than that of non-outburst debris flow.