摘要
以全新世戈龙布古滑坡堵江溃决洪水地质灾害链为例,采用野外调查、PFC3D滑坡动力学数值模拟和HEC-RAS溃决洪水模拟,再现了该滑坡滑‒堵‒溃灾害链全过程.首先通过野外调查查明了该滑坡的特征,戈龙布滑坡总体积约7.92×10^(7)m^(3),主滑方向为NW335°,最大滑动距离为2.3 km,最大堆积厚度约150 m.利用离散元软件对该滑坡启动和堆积过程模拟,戈龙布滑坡滑动过程持续了103 s,最大速度可达57 m/s,且在滑动过程中呈现出破碎程度区域差异性的运动学特性;大部分颗粒在运动过程中保持了其原始的位置顺序,堆积体物质特点为单个颗粒与块体团簇共存,破碎作用较弱.滑坡堆积体面积约为1.8×10^(6)m^(2),鞍部高143 m,左岸、右岸高程分别为2030 m和2063 m.滑坡堵塞黄河形成的堰塞坝厚度达143 m,上游形成面积为128 km^(2)、库容为4.87×10^(9)m^(3)的堰塞湖.通过模拟不同溃坝程度(15%、25%、50%和75%)下洪水演进过程,溃口下泄流量在30 mins内迅速增大达到一个顶峰,然后呈缓速减小;溃口最大峰值流量分别为15137.9 m^(3)/s、52192.9 m^(3)/s、157375.5 m^(3)/s和326703.6 m^(3)/s,并分析了下游各断面的洪峰流量和水位特征.讨论了洪水演进与喇家遗址的关系,发现在25%溃坝时,溃口洪峰流量为52192.9 m^(3)/s,喇家遗址处水深为27.1 m;75%溃决时,到达二里头遗址的最大流量相当于黄河百年一遇洪水流量.研究结果对开展黄河上游古滑坡动力学过程和溃决洪水研究具有一定的参考.
This paper takes the Holocene Gelongbu ancient landslide blocking the river outburst flood geological disaster chain as an example,using field surveys,PFC3D landslide dynamics numerical simulation and HEC-RAS outburst flood simulation to reproduce the whole process of the landslide slip-blocking-break disaster chain.It is found in field investigations that the total volume of Gelongbu landslide is about 7.92×10^(7)m^(3),the main sliding direction is NW335°,the maximum sliding distance is 2.3 km,and the maximum accumulation thickness is about 150 m.The materials at the front edge of the landslide are looser than those at the back edge,and the degree of fragmentation is higher.The numerical simulation shows that the sliding process of Gelongbu landslide lasts for 103 s,and the maximum velocity can reach 57 m/s.In the sliding process,the kinematic characteristics of the sliding process showed regional differences in the degree of fragmentation.Most of the particles maintained their original positions during the motion,and the accumulation material consisted of individual particles and block clusters with relatively weak fragmentation.The landslide blocked the Yellow River and formed a barrier dam as high as 143 m at the saddle point and elevations of 2030 m on the left bank and 2063 m on the right bank.The area of the landslide accumulation body is approximately 1.8×10^(6)m^(2),forming an upstream reservoir with an area of 128 km^(2)and a storage capacity of 4.87×10^(9)m^(3).By simulating the flood evolution process under different degrees of dam break(15%,25%,50%,and 75%),it was observed that the outflow from the breach rapidly increased to a peak within 30 minutes,followed by a gradual decrease in velocity.The peak outflow from the breach at different levels of dam break were 15137.9 m^(3)/s,52192.9 m^(3)/s,157375.5 m^(3)/s,and 326703.6 m^(3)/s,respectively.The peak flood discharge and water level characteristics at various downstream sections were analyzed.The relationship between flood evolution and the Lajia Site is discussed.It is found that the peak discharge of the burst flood is 57782.3 m^(3)/s when the dam breaks at 25%,and the water depth at the Lajia Site is 27.1 m,which is 6.1 m above the ancient surface of the site.When 75%of the dam breaks,the maximum flow to Erlitou Site was equivalent to the once-in-100-year flood flow of the Yellow River.
作者
贾珂程
庄建琦
占洁伟
王世宝
牛鹏尧
牟家琦
王杰
郑佳
付玉婷
Jia Kecheng;Zhuang Jianqi;Zhan Jiewei;Wang Shibao;Niu Pengyao;Mu Jiaqi;Wang Jie;Zheng Jia;Fu Yuting(College of Geological Engineering and Geomatics,Chang’an University/Key Laboratory of Western China’s Mineral Resources and Geological Engineering,Ministry of Education,Xi’an 710054,China;Zhejiang Communications Construction Group Co.,Ltd.,Hangzhou 310051,China)
出处
《地球科学》
EI
CAS
CSCD
北大核心
2023年第9期3402-3419,共18页
Earth Science
基金
国家自然科学基金项目(Nos.41941019,41922054)
国家重点研发计划项目(No.2020YFC1512000).
关键词
黄河
积石峡
堰塞湖
溃坝
喇家遗址
工程地质
灾害防治
Yellow River
Jishi gorge
dammed lake
dam⁃failure
Lajia Site
engineering geology
disaster prevention
