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冰川冻土 ›› 2016, Vol. 38 ›› Issue (3): 662-670.doi: 10.7522/j.issn.1000-0240.2016.0073

• 寒区科学与技术 • 上一篇    下一篇

甘肃永靖黑方台4·29罗家坡黄土滑坡的特征

吴玮江1, 叶伟林2 1, 姚正学1, 杨涛1, 魏万鸿1, 刘伟3   

  1. 1. 甘肃省科学院 地质自然灾害防治研究所, 甘肃 兰州 730000;
    2. 兰州大学 资源环境学院, 甘肃 兰州 730000;
    3. 兰州大学 土木工程与力学学院, 甘肃 兰州 730000
  • 收稿日期:2016-03-15 修回日期:2016-05-08 出版日期:2016-06-25 发布日期:2016-09-21
  • 作者简介:吴玮江(1963-),男,甘肃天水人,研究员,1983年毕业于西安地质学院,现主要从事工程地质与地质灾害防治研究.E-mail:wwj0408@163.com
  • 基金资助:
    国家自然科学基金项目(41362014);甘肃省科学院项目(2012jk-07;2015jk-01;2013QN-13)资助

Characteristics of the Luojiapo loess landslides at Heifangtai,burst on April 29,2015,in Yongjing County,Gansu Province

WU Weijiang1, YE Weilin2 1, YAO Zhengxue1, YANG Tao1, WEI Wanhong1, LIU Wei3   

  1. 1. Geological Hazards Prevention Institute, Gansu Academy of Sciences, Lanzhou 730000, China;
    2. College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, China;
    3. School of Civil Engineering and Mechanics, Lanzhou University, Lanzhou 730000, China
  • Received:2016-03-15 Revised:2016-05-08 Online:2016-06-25 Published:2016-09-21

摘要: 2015年4月29日上午,甘肃省永靖县盐锅峡镇黑方台滑坡高频发区的党川村罗家坡同一斜坡处连续发生了2次大规模黄土滑坡,总体积约65×104m3,最大滑距630m,摧毁14户居民房屋和3家工厂。通过现场详细调查、取样试验、1∶500地形测量、滑坡影像、视频等资料分析,对灌溉引发的罗家坡黄土滑坡的特征、滑动过程、形成机理进行了探讨。结果表明:第1次滑坡经过近2a变形过程,整体突然失稳,高速远程滑动;第2次滑坡变形时间仅3h,分块逐步滑动,滑动历时长而过程复杂,总体为低速远程滑动。高陡的地形和强度低、水敏感性强的土体是滑坡发生的基础,黄土台塬区长期农业灌溉是引发因素,大量水体入渗形成了20余米厚的饱和软弱基座,使抗剪强度降低,导致斜坡失稳滑动。黄土滑坡高速远程滑动的主要原因是滑坡剪出口位置高,滑动势能大,释放条件好,剪出口下部陡坡段为主要加速段;前方有开阔的滑动空间且有一定坡度、平缓的滑道;滑体底部饱和软弱黏性土在滑道上持续产生超孔隙水压力、液化等低摩阻效应,是远程滑动的润滑剂。同时,两次滑体间还存在冲击加速和能量传递作用。

关键词: 黄土滑坡, 特征, 高速远程, 农业灌溉, 地下水, 黑方台

Abstract: In the morning of April 29,2015,two large-scale loess landslides occurred continuously at Luojiapo of Dangchuan Village of Yongjing County,Gansu province. The total volume is about 65×104m3,with the maximum sliding distance of 630 m,and 14 households and 3 factories destroyed. Based on the analyses of detailed investigation in situ,sampling test,1:500 topographic survey and video data of the landslides,the landslide features, formation mechanisms and sliding processes are discussed about. It is believed that the Luojiapo Landslides are loess landslide induced by irrigation. The result show that the first landslide had experienced deformation accumulation for two years,and then collapsed with high speed and long distance. The second landslide had experienced deformation accumulation only 3 hours,sliding block by block,lasting a long time and a complicated process,which was low speed and long distant slide. The basal condition of landslide is high and steep terrain and soil of low strength and water sensitivity;artificial factor is long-term agricultural irrigation in the loess platform tableland. When the thickness of saturated soft foundation reaches about 20 m,in case of a large number of water infiltrating in,it will lower the shear strength,and then lead to instability of the loess. The main conditions of loess having high-speed sliding for a long distance are a high position of landslide burst export,a large sliding potential with good release condition and a steep slope at the bottom. It is very important to have an excess pore water pressure caused by saturated soft clay at the bottom of the sliding body,resulting in low friction effect due to liquefaction.

Key words: loess landslide, characteristics, high-speed & long distance, agricultural irrigation, groundwater, Heifangtai

中图分类号: 

  • P642.22