摘要
1933年发生在青藏高原东缘岷江上游叠溪地区的7.5级地震,致岷江干流两岸岩体崩滑堵江,形成叠溪小海子堰塞湖。堰塞湖形成后,水流携带松坪沟流域内的泥砂进入堰塞湖不断沉积,形成具有顶积层、前积层和底积层3层结构的吉尔伯特型扇三角洲。基于野外调查,本文对叠溪堰塞湖三角洲沉积物的沉积特征进行研究,依据沉积物的地貌和沉积特征推断松坪沟流域至少发生过两次大型洪水事件。采用水力学中的水流能量法反演计算,结果表明这两次洪水的最大洪峰流量分别为405.4 m^(3)·s^(-1)和365.4 m^(3)·s^(-1)。叠溪堰塞湖沉积特征与历史洪峰流量的重建,对于了解震后堰塞湖地质环境及演化规律等方面具有重要意义,可为地质灾害等事件的发生频率、危害程度在工程建设方面提供参考。
The Diexi earthquake of 7.5 magnitudein 1933 is located at the upstream area of Minjiang River,the east of the Tibetan Plateau.It caused that the rocks at the two sides of the Minjiang River collapsed and blocked Minjiang River,and formed a barrier lake entitled“Diexi Xiaohaizi”.After the barrier lake formed,the soil and sand from Songping Valley entered and sunk into the barrier lake successively.It formed gilbert-type fan delta showing threefold subdivision into topset,foreset,and bottomset strata.Songping valley had at least two catastrophic flood events happened according to the landform of the sedimentary bodies and the sedimentary facies characteristics.The study on the deposit characters and causes of Songping ditch accumulation body is combined with flow energy method in dynamics to back calculation.It supplied a new method and thoughts for learning the mountainous geological environment and the occurrence frequency and damage degree of the geological hazard evolution and so on events.
作者
杨凌崴
余斌
何元勋
刘峰焰
马啸宇
李阳春
YANG Lingwei;YU Bin;HE Yuanxun;LIU Fengyan;MA Xiaoyu;LI Yangchun(State Key Laboratory of Geohazard Prevention and Geoenvironment Protection,Chengdu University of Technology,Chengdu 610059,China)
出处
《工程地质学报》
CSCD
北大核心
2022年第3期884-895,共12页
Journal of Engineering Geology
基金
国家自然科学基金(资助号:U21A2032)
地质灾害防治与地质环境保护国家重点实验室自主研究课题(资助号:SKLGP2017Z002)。
关键词
三角洲沉积
演化机制
历史洪水
堰塞湖
岷江叠溪
Barrier lake
Delta deposit
Evolution mechanism
Historic flood
Diexi
Minjiang
