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地质力学学报:2020,26(4):471-480
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地震作用下西藏易贡滑坡动力响应特征分析
(1.中国地质科学院地质力学研究所, 北京 100081;2.新构造运动与地质灾害重点实验室, 北京 100081;3.中国地质环境监测院, 北京 100081)
An analysis of dynamic response characteristics of the Yigong Landslide in Tibet under strong earthquake
(1.Institute of Geomechanics, Chinese Academy of Geological Sciences, Beijing 100081, China;2.Key Laboratory of Neotectonic Movement and Geohazard, Beijing 100081, China;3.China Institute of Geological Environment Monitoring, Beijing 100081, China)
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投稿时间:2020-05-20    修订日期:2020-06-29
中文摘要: 西藏雅鲁藏布江大峡谷地区是地震滑坡的高易发区,发生过多期地震滑坡。以西藏易贡滑坡为例,运用FLAC3D有限差分方法,对滑坡所在山体进行频响特征分析,并以此为基础对其地震波作用下的放大效应开展研究,最后对近场强震条件下山顶潜在崩滑体稳定性进行预测。研究结果发现:易贡山体整体卓越频率处于较低值,山顶卓越频率主要集中在1 Hz以下、山顶两侧卓越频率在2~6 Hz之间;在地震波作用下,易贡山体顶部及两侧出现不同程度放大,山体内部沿高度向上呈先增后减、进而再次增大的变化趋势,其计算结果与频响特征分析结果基本一致;静力条件下,潜在崩滑体基本保持稳定,其安全系数为1.27,但地震作用下的计算结果却表明其发生了失稳破坏;在考虑水平向和竖向加速度同时输入的近场强震条件下,崩滑体稳定程度将进一步下降,因此需加强近场强震条件下山体的风险分析及预测。
Abstract:The Yarlung Zangbo River Grand Canyon area in Tibet is a highly prone area for earthquake-triggered landslides, where several landslides have occurred before. Taking the Yigong Landslide as an example, this article analyzes the frequency response characteristics of the Yigong Mountain by using the FLAC3D finite difference method. Based on the results, the amplification effect of the Yigong Mountain under seismic waves is discussed and the stability of the Yigong Landslide remnant under the condition of near-field strong earthquakes is predicted. Results show that the overall predominant frequency of the Yigong Mountain is at a low value. The predominant frequencies of the mountain top mainly concentrate below 1 Hz, while that of both sides of the mountain top vary from 2~6 Hz. Under the action of seismic waves, the predominant frequencies of the top and both sides of the mountain appear different degrees of amplification, and that in the mountain interior along the height upward shows the change of first increasing then decreasing, and then increasing again. The calculated results are basically identical with the frequency analysis. Stability analysis shows that the Yigong Landslide remnant keeps stable with a safety factor of 1.27 in static condition; however, the results under the earthquake show the occurrence of instability and failure. Finally, it is predicted that the damage of the Yigong Landslide remnant will obviously increase when considering both horizontal and vertical seismic waves. Therefore, it is necessary to strengthen the risk analysis and prediction of mountains under the condition of near-field strong earthquakes.
文章编号:     中图分类号:P642.22    文献标志码:
基金项目:国家重点研发计划项目(2018YFC1504806);国家自然科学基金项目(41702342)
引用文本:
刘铮,李滨,贺凯,等,2020.地震作用下西藏易贡滑坡动力响应特征分析[J].地质力学学报,26(4):471-480.DOI:10.12090/j.issn.1006-6616.2020.26.04.040
LIU Zheng,LI Bin,HE Kai,et al,2020.An analysis of dynamic response characteristics of the Yigong Landslide in Tibet under strong earthquake[J].Journal of Geomechanics,26(4):471-480.DOI:10.12090/j.issn.1006-6616.2020.26.04.040

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