2012年8月18日,四川彭州龙门山镇白水河上游暴发大型泥石流灾害,境内发生泥石流60余处,20条沟谷型泥石流沿白水河两岸成不对称分布,右岸泥石流破坏尤为严重。泥石流细颗粒含量低于2%,容重1.74~1.91g/cm3,流速6.9~12.6m/s,流量360~1274m3/s,具有群发性、高容重、过渡性、高速、大流量和暴雨—滑坡—泥石流—堰塞湖—溃决洪水灾链过程等特点。泥石流通过冲刷破坏、淤埋破坏、淤埋与损毁路基等方式直接造成损失,溃决洪水、河床上升增大受灾范围,加重了灾害损失。对震后泥石流危险性认识不足、灾后重建工程选址不当,防治工程标准偏低、损毁严重为造成重大损失的主要原因。研究区泥石流长期处于活跃期,建议通过强化泥石流活动趋势分析与预测、加强重点沟谷泥石流风险评价、注重灾链与河床升高效应进行科学选址、依据震后特点进行泥石流防治、尽快重建滑坡断道路段、提高防灾减灾意识与技能等措施减轻泥石流灾害。 更多还原

 

The catastrophic debris flows on Aug.18, 2012 resulted in huge property loss in Longmenshan Town, Pengzhou, China. Debris flows occurred in 60 sites and 20 gully debris flows distributed along Baishui River, intensively destroyed the buildings at the right bank. Debris flows were featured with less than 2% of fine soil content, the density of 1.74~1.91g/m3, the peak discharge of 360~1 274m3/s as well as the process of rainstorm-landslide-debris flow-dammed lake-outburst flood. The discharge of debris flow remarkably amplified in small gullies,equaling to 5.0~29 times that before Wenchuan Earthquake. High-velocity and large discharge debris flows made direct hazards by intensively impacting, scouring and burying constructions as well as burying and destructing highway base. Outburst flood and river channel rise induced by debris flows enlarged the stricken areas and losses. The irrational location of constructions and the destruction of debris flow control constructions leaded to huge property losses. Encountering the active debris flow hazards in the future, it was strongly suggested for mitigation that strengthened the prediction of debris flows change trend, assessed risk of the dangerous debris flow gullies, relocated reconstruction based on debris flow risk assessment, improved the standards of control construction, reconstructed destructed highway at Xiaojiaping and improved the capabilities of prevention and mitigation.