旭龙水电站茂顶河泥石流活动特征分析与危险性评价

Activity characteristic analysis and risk assessment for Maoding river deberis flow of Xulong Hydropower Station

旭龙水电站施工场地非常有限,茂顶河出口段处于施工区,其活动特征、规模及影响程度等将直接影响施工区安全。对旭龙水电站茂顶河泥石流进行了活动特征与危害性评价研究。结果表明:①主沟与1号沟为低频稀性泥石流,1-1号沟与1-2号沟为高频黏性泥石流;②按洪痕调查计算的泥石流流量与按清水洪峰流量和配方法计算的泥石流流量结果基本一致;③按20 a一遇计算,茂顶河泥石流峰值流量377 m^(3)/s,最大流速6 m/s,泥石流总量约11.9万m^(3);20,50,100 a一遇的茂顶河泥石流的危险等级分别为无直接危害、轻度危险、中等危险。经综合分析,对茂顶河泥石流采用了“停淤坝+排导槽+拦挡坝”的防治方案。

The construction site of Xulong hydropower station is very limited,and the outlet section of the Maoding river is in the construction area.The activity characteristics,scale and impact degree of debris flow in the Maoding river basin will directly affect the safety of the construction area.The activity characteristics and hazard assessment of debris flow of the Maoding river are studied for Xulong Hydropower Station.The results show that:①there are low-frequency rarefied debris flows in the main gully and No.1 gully,and high-frequency viscous debris flows in No.1-1 gully and No.1-2 gully;②the debris flow discharge calculated by flood trace investigation is basically consistent with that calculated by clear water peak discharge and distribution method;③according to the calcula⁃tion of 20 years return period,the peak flow of debris flow in the Maoding river is 377 m^(3)/s,the maximum flow ve⁃locity is 6 m/s,and the total volume of debris flow is about 119000 m^(3);the hazard levels of debris flow in the Maod⁃ing river with return periods of 20,50 and 100 years are no direct hazard,mild hazard and medium hazard respec⁃tively.The prevention scheme of"desilting dam+drainage channel+retaining dam"is adopted for debris flow in the Maoding river basin.