岷江上游大白杨沟泥石流特征及成因.pdf

第26卷第1期
现代地质
Vol 26 Na I
2012年2月
GEOSCIENCE
Feb.2012
岷江上游大白杨沟泥石流特征及成因
吴雨夫,余斌,亓星,诸胜名,李丽
(成都理工大学地质灾害防治与地质环境保护国家重点实验室,四川成都610059)
摘要:大白杨沟流域位于岷江上游四川省茂县境内,处于叠溪镇较场山字型构造北端。该沟曾于1935年和1991年暴
发过两次较大规模泥石流灾害,其中1935年暴发的泥石流受1933年叠溪75级地震影响,规模很大,其泥石流峰值流
量达到557m3/a。通过对大白杨沟流域两条支沟(小沟、大沟)的地形条件、水源条件及物源条件的特征分析,得出两
条支沟具有形成泥石流的充分条件:(1)大沟沟道平均纵比降275%,小沟为398%,相对高差达2023m;(2)大沟拥
有的物源总量为29.21万m3,小沟达到42.01万m3,物源丰富。这些条件很好地解释了小沟泥石流的强活动性。对后
期泥石流的形成机制进行分析,大沟以“消防水管效应”形成泥石流为主,小沟则以“消防水管效应”和堰塞体溃决两种
方式形成泥石流。最后,通过泥痕法还原了历史泥石流流量,并对后期泥石流流量做了较合理的预,为大白杨沟泥
石流灾害防治提供可靠的数据
关键词:大白杨沟;泥石流;地震;特征;成因机制;岷江上游
中图分类号:P42.23
文献标志码:A
文章编号:1000-8527(2012)01-0107-07
Features and Formation Mechanism of Debris Flow in Dabaiyang Gully
in Upper Reaches of Minjiang River
WU Yu-fu, YU Bin, QI Xing, CHU Sheng-ming, LI Li
(SuekeylaboruorygfeohardsPeunionandeonironwnemPoaciwn,ChaengdhtUhniiygTethnodogy,Cngd血t,Sichon61009,China
Abstract The Dabaiyang gully is located at the Jiaochang epsilon-type structure in the north of Diexi town
Maoxian County, Sichuan Province, which is in upper reaches of Minjiang River. Two large-scale flow debris
events occurred in the gully in 1935 and 1991, and the flow debris in 1935 was caused by the 1933 Diexi Earth
quake (M =7.5) which is huge with peak flow of 557 m/s. After the analysis of the landform, available loose
materials and water conditions of two tributaries(Dagou and Xiaogou gullies )in Dabaiyang gully, it was ob-
tained that there are sufficient conditions for the formation of tributary debris flow, which explains the intense
activity of debris Mlow in the Xiaogou gully: (1 the average longitudinal gradient is 275%in the Dagou ull
and 398% in the iaogou gully, and the relative ali ude s 2, 23 m )he tal amount of loose materials is
292, 100 m in the Dagou gully and 420, 100 m in the Xiaogou gully, and the source of materials is abundant
The formation mechanism of debris flow was also analyzed. It reveals that the formation of debris flow caused by
the fire hose effect in the Dagou gully, and by the fire hose effect and the burst of barrage body in the Xiaogou
gully. The flux of historical debris flow was calculated by mud trace investigation method, and the flux of future
debris flow was appropriately forecasted, which provides valuable data for preventing debris flow disaster in
Dabaiyang gully
Key words: Dabaiyang gully; debris flow; earthquake; feature; formation mechanism; upper reaches of Min
iang River
收稿日期:2011-07-29;改回日期:2011-11-22;资任编:潘令枝。
基金项目:国家自然科学基金项目(40871054)。
作者简介:吴雨夫,男,硕土研究生,助理工程师,1985年出生,地质工程专业,主要从事地质灾害防治工程和工程物探的研
究工作。 Email. thud@ cp com。
万方数据