Abstract: The authors discuss roundly source of loose earth for impact deposit debris flow to develop taking pingchuan debris flow,one of the quite typical impact deposit debris flows in southwest sichuan province,as an example in this paper. on the basis of detailed investigations in situ,geotechnial testing in Lab and theory analysis,all results indicate obviously that moderate and bulky loose earth in giant debris flow situating in southwest sichuan mountainous area are main institute,whose tribulation are consistent with landforms.Loose earth locating in mid forepart catchment are quite unstable,so often becomes main source of loose earth of debris flow.Formation of loose earth is controlled principally by geologic and geotechnical environment while human actions is the secondary factor for loose earth to form.In many times,human actions provide loose earth through loose earth stability.

Key words: geotechnical stability, impact deposit debris flow, loose earth, source

摘要： 本文以极具典型的平川泥石流为例比较全面的分析了冲淤变动型泥石流的物源问题 .根据现场调研及室内岩土分析进行的研究成果显示,川西南高山深谷地区的大型泥石流沟中的松散土体以中、粗粒段为主,其分布与地形密切相关;位于泥石流沟中、前部位的松散土体的稳定性最差,是补给泥石流的重要物源;松散土体的发育主要受控于地质及岩土环境,人类活动只能影响松散土体的稳定性

关键词: 岩土稳定性, 冲淤变动型泥石流, 松散土体, 物源