| 基于InSAR形变监测的四川甲居古滑坡变形特征 |
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| 引用本文： | 闫怡秋,郭长宝,钟宁,李雪,李彩虹.基于InSAR形变监测的四川甲居古滑坡变形特征[J].地球科学,2022,47(12):4681-4697. |
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| 作者姓名： | 闫怡秋 郭长宝 钟宁 李雪 李彩虹 |
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| 作者单位： | 1.中国地质科学院地质力学研究所, 北京 100081 |
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| 基金项目： | 国家自然科学基金项目41877279国家自然科学基金项目41731287国家自然科学基金项目42007280中国地质调查局项目DD20190319 |
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| 摘 要： | 位于四川省丹巴县聂呷乡甲居村的甲居古滑坡主要由甲居滑坡(H01)、聂呷坪滑坡(H02)、小巴旺村滑坡(H03)、聂拉村滑坡(H04)和山顶滑坡(H05)等5个次级滑体组成.受区域构造、强降雨、河流侵蚀、地层岩性等因素影响，甲居古滑坡次级滑体持续发生蠕滑变形，对位于滑体上的村庄、道路和前缘大金河等具有较大危害，2020年遭受50年一遇的强降雨后，古滑坡变形速率有进一步增大的趋势.采用SBAS-InSAR技术，结合遥感解译和现场调查，获取了甲居古滑坡2018年6月至2021年8月的地表变形特征，通过二维形变速率转换获取了甲居古滑坡沿斜坡向(slope)和垂直向(vertical)的形变速率.研究认为，甲居古滑坡沿雷达视线方向(VLOS)形变速率最大达-179 mm/a，沿斜坡方向的形变速率(Vs)最大为-211 mm/a，沿垂直方向的变形速率(Vv)最大为-67 mm/a.甲居滑坡的北侧区域、聂拉村滑坡的南侧区域和山顶滑坡后缘变形较大，总体上位于强变形-极强变形区.甲居古滑坡的变形机制具有一定差异，其中甲居滑坡以牵引式变形为主，聂拉村滑坡以推挤式变形为主.由于古滑坡地质构造复杂、新构造活动强烈，在强降雨和河流侵蚀作用下极易导致滑坡蠕滑速率加快并进一步失稳，形成堵江溃坝等灾害.建议加强次级滑体的地表变形监测，为流域性地质安全风险防灾减灾提供技术支撑和科学依据.
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| 关 键 词： | 丹巴甲居 古滑坡 SBAS-InSAR 形变监测 二维形变转换 工程地质 |
| 收稿时间： | 2022-09-05 |
Deformation Characteristics of Jiaju Ancient Landslide Based on InSAR Monitoring Method,Sichuan, China |
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| Abstract: | The Jiaju ancient landslide,located in Jiaju Village,Niexia Township,Danba County,Sichuan Province,is mainly composed of 5 secondary sliding bodies,such as Jiaju landslide (H01),Niexiaping landslide (H02),Xiaobawang Village landslide (H03),Niela Village landslide (H04),and the mountain top landslide (H05). Affected by factors such as regional structure,heavy rainfall,river erosion,stratigraphic lithology,etc.,the secondary sliding bodies of Jiaju ancient landslide continue to undergo creep deformation,which will cause certain harm to villages,roads and the front edge of Dajin River. The deformation rate tends to increase further after the occurrence of heavy rainfall that occurs once every 50 years in 2020. In this paper it uses SBAS-InSAR technology,combined with remote sensing interpretation and field investigation,obtained the surface deformation characteristics of the Jiaju ancient landslide from June 2018 to August 2021, and obtained the edge of the Jiaju ancient landslide through two-dimensional deformation rate conversion,the slope and vertical deformation rates. The research shows that the maximum deformation rate of the Jiaju ancient landslide along the radar line of sight (VLOS) is -179 mm/a,the maximum deformation rate along the slope direction (Vs) is -211 mm/a,and the maximum deformation rate along the vertical direction (Vv) is -67 mm/a. The northern area of the Jiaju landslide,the southern area of the Niela Village landslide,and the trailing edge of the mountain top landslide are largely deformed,and are generally located in the strong deformation-extremely strong deformation area. The deformation mechanisms of the Jiaju ancient landslide are different to some extent. The Jiaju landslide is dominated by traction deformation,while the Niela Village landslide is dominated by push deformation. Due to the complex geological structure of the ancient landslide and the strong neotectonic activity,under the action of heavy rainfall,it is easy to cause the landslide creep rate to accelerate and further destabilize,resulting in dammed lake and dam broken hazards. It is suggested to strengthen the surface deformation monitoring of secondary sliding bodies to provide technical support and scientific basis for geohazard prevention and mitigation of watershed geological safety risks. |
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