基于SBAS-InSAR的黄河干流军功古滑坡形变分析

Deformation Analysis of Jungong Ancient Landslide Based on SBAS-InSAR Technology in the Yellow River Mainstream

2019-09-20,中国青海省玛沁县拉加镇军功古滑坡发生局部失稳,导致公路交通中断,严重威胁当地居民生命财产安全,亟需查明古滑坡的形变区和形变规律,为防治工程设计和监测预警提供参考。首先利用高分辨率卫星影像和数字高程模型数据并结合现场调查,基于滑坡形态特征和形变迹象对古滑坡进行分区;然后利用2017-01-2020-12的Sentinel-1雷达卫星降轨数据,基于小基线集合成孔径雷达干涉测量技术(small baseline subset interferometric synthetic aperture radar,SBAS-InSAR)对古滑坡的地表形变特征和形变规律进行分析。基于滑坡形态特征和变形迹象,将古滑坡分为4个次级滑坡区,SBAS-InSAR形变结果显示古滑坡整体处于持续的缓慢蠕滑状态。滑坡强变形区主要位于公路开挖段,人类活动对古滑坡稳定性扰动较大,滑坡强变形区形变速率与降雨具有较好的响应关系。虽然古滑坡局部已进行了抗滑桩等工程治理,但由于古滑坡存在多级滑面,已有抗滑桩深度不够,虽发挥了一定的抗滑作用,但未起到完全阻止滑坡整体蠕滑变形的作用,建议后续治理工程应利用钻探等勘察技术手段查明多级滑面深度后进行设计施工,并在强形变区安装裂缝计等现场实时监测预警设备,结合雷达卫星InSAR中长期监测,实现对该滑坡点、面结合的监测预警。

Objectives:On September 20,2019,the Jungong ancient landslide in Lajia Town,Maqin County,Qinghai Province,China suffered a local failure,which led to the interruption of traffic and seriously threatened the safety of local residentslives and properties.It is urgent to find out the deformation area and deformation law of the ancient landslide,and to provide the support for prevention and control engineering design,monitoring and early warning.Methods:First,using high-resolution satellite images,digital elevation model data and combined with field investigations,the ancient landslide were zoned based on landslide morphological characteristics and signs of deformations;further,Sentinel-1 radar satellite descending data from January 2017 to December 2020 were used to analyze the surface deformation characteristics and deformation patterns of the ancient landslide based on small baseline subset interferometric synthetic aperture radar technology(SBAS-InSAR).Results:Based on the morphological characteristics and deformation signs of the landslide,the ancient landslide was divided into four sub-areas.The SBAS-InSAR results show that the ancient landslide is in a continuous slow creeping state.The strong deformation area of the landslide is mainly located in the road excavation section.Human activities greatly disturb the stability of the ancient landslide.The deformation rate of the strong deformation area of the landslide has a good relationship with rainfall.Conclusions:Although the ancient landslide has been partially treated with anti-slide piles and other projects,the ancient landslide has multi-level sliding surfaces,and the depth of the existing anti-slide piles is not enough.Although the ancient landslide has played a certain role in anti-slide,it has not completely prevented the creep deformation of the landslide.It is suggested that the subsequent treatment projects should use drilling and other exploration techniques to find out the depth of the multi-level sliding surfaces before designing,and installing onsite real-time monitoring and early warning equipment such as crack meters in the strongly deformed areas.Combined with the medium and long-term monitoring of radar satellite InSAR,a point-surface monitoring and early warning system could be realized.