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白鹤滩水电站坝址近场区受多条泥石流沟的威胁,为降低泥石流灾害造成的损失,建立基于临界雨量的预警系统是行之有效的途径。首先,收集该区泥石流活动历史资料及相应的降雨资料,通过灾害实例调查法及频率法分别推算该区24 h临界雨量、10 min及1 h临界雨量值范围。结合区域泥石流活动特点、该区降雨特征及泥石流启动原位试验,确定该区的24h临界雨量、10min及1h防范雨量及预警指标(临界雨量)。经综合分析后确定24 h临界雨量为10 mm(有前期降雨)及38.14 mm(无前期降雨);10 min降雨量介于6.41~8.84 mm或1 h雨量介于13.63~18.78 mm为该区防范雨量值;8.84 mm及18.78 mm为10 min及1h泥石流预警指标,即该区泥石流临界雨量。根据该区各沟泥石流活动情况、泥石流自身复杂性及该工程的重要性,提出该区泥石流防治建议,以期为该区泥石流预报及防灾减灾提供参考。
The near site of Baihetan Hydropower Station dam site is threatened by multiple debris flow ditches. To reduce the losses caused by debris flow disasters, it is an effective way to establish early warning system based on critical rainfall. First, historical data of debris flow activity and corresponding rainfall data are collected. Based on the disaster case investigation method and frequency method, the critical rainfall of 24 h, the critical rainfall value of 10 min and 1 h are calculated respectively. Combined with the characteristics of debris flow activities in the area, the rainfall characteristics of the area and the in-situ tests of debris flow start-up, the critical rainfall of 24 hours, the rainfall prevention and warning index (critical rainfall) of 10 min and 1 h were determined. The comprehensive analysis shows that the critical rainfall at 24 h is 10 mm (with pre-rainfall) and 38.14 mm (without previous rainfall), and the rainfall at 10 min is 6.41 8.84 mm or the rainfall is between 13.63 and 18.78 mm at 1 h The rainfall value; 8.84 mm and 18.78 mm are the early warning indicators of debris flow for 10 min and 1 h, that is, the critical rainfall for debris flow in this area. According to the activity of debris flow in each gully of the area, the complexity of debris flow itself and the importance of the project, the paper put forward the proposal of prevention and control of debris flow in this area, in order to provide reference for the debris flow forecasting and disaster prevention and mitigation in this area.