摘要
元谋干热河谷区沟蚀崩塌发育充分,沟蚀的发育与崩塌的发生相互依存,相互促进。通过对元谋干热河谷沟蚀发育阶段和崩塌类型的全面调查和采样分析,研究沟蚀发育与崩塌类型的关系。结果表明:研究区沟蚀发育一般分为浅沟、切沟、冲沟和残丘夷平谷4个阶段;一般情况下,浅沟阶段不发生崩塌,切沟阶段沟头的坠落式崩塌促进沟头的前进,冲沟阶段沟壁的滑移式崩塌促进沟岸的扩张,残丘夷平谷阶段土柱下部土体剥落,为倾倒式崩塌创造条件,土柱的倒塌使冲沟逐渐被填平,形成夷平谷。通过对影响沟蚀发育和崩塌发生的因素进行分析,表明在元谋组地层上,砂土和黏土由粗向上变细的渐变式正向沉积旋回,特殊的土体构型以及干热干湿分明的气候特征,是沟蚀发育和不同类型崩塌发生的根本原因。
Gully erosion and collapse fully developed in Yuanmou Dry-Hot Valley area.The development of gullying and the occurrence of collapse are interdependent and mutually promotive.Their relationships are studied based on a general survey of the gullying development stage and collapse type.Results show that gullying development process has the four stages： shallow gully stage,gully stage,gulch stage and valley stage in Yuanmou Dry-Hot Valley area.Generally,there is no collapse occurrence in shallow gully stage.The falling collapse of gully head promotes the gully head advance in gully stage.The sliding collapse of gully sidewall accelerates the gully bank extension in gulch stage.The exfoliation in the lower soil column forms the condition for the toppling collapse of soil column in valley stage when the gully is gradually razed by the collapse of soil column.By analyzing the affecting factors of gullying development and collapse occurrence,it can be concluded that the three aspects,including graded positive sedimentary cycle of lower sand and upper clay from coarse to fine in the Yuanmou Formation,the special soil body structure,and the dry-hot climate and distinct wet-dry seasons,are the basic causes of the gullying development and the occurrence of different collapse types.
出处
《中国水土保持科学》
CSCD
2011年第4期1-6,22,共7页
Science of Soil and Water Conservation
基金
国家自然科学基金项目"金沙江干热河谷冲沟溯源侵蚀机理研究"(41071013)
国家支撑计划课题"长江中上游西南山区退化生态系统综合整治技术与模式"(2006BAC01A11)
关键词
沟蚀发育
崩塌类型
地质构造
干热河谷
gullying development
collapse type
geological structure
Dry-Hot valley
