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| Relationship between gullying development stage and collapse type in Yuanmou Dry-Hot Valley area |
| Chen Anqiang1, 2, 3, Zhang Dan1, 2, 3, Fan Jianrong1, Liu Gangcai1, 3 |
| (1. Institute of Mountain Hazards and Environment, Chinese Academy of Science & Water Resources Ministry, 610041, Chengdu; 2. Graduate University of Chinese Academy of Sciences, 100049, Beijing;
3. Key Laboratory of Mountain Hazards and Earth Surface Processes, Chinese Academy of Sciences, 610041, Chengdu: China) |
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Abstract 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.
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Received: 28 February 2011
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| Fund: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） |
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