既有线季节性冻土时序DInSAR沉降监测

Time-Series DInSAR Technique for Settlement Monitoring of Seasonal Frozen Soil Area on Operating Railway

季节性冻土的冻胀和融沉对铁路既有线路基、边坡以及周围设施的冻害多呈区域性和周期性,传统监测技术手段难以达到足够的时空分辨率,引入毫米级时序DInSAR技术十分必要。选取季节性冻土较发育的黑龙江某既有线作为研究对象,根据其沿线区域地形和地质特点,采用针对性的选点方法以及基于多主影像干涉的时序DInSAR误差改正及解算模型,使用时间基线长达两年(2017年9月至2019年7月)的高时间密度48景中等分辨率Sentinel-1A SAR影像,获取自联调联试至目前运营期间沿线区域沉降的时空分布结果,通过与该区域冻融时间点的联合分析,获得冻土冻胀和融沉对铁路沿线区域沉降影响的时空分布规律,可为该区域季节性冻土的时空演变规律提供参考数据。

The frost heave and thaw settlement of seasonal frozen soil have regional and periodic frost damage to operating railway line foundations,slopes and surrounding facilities.It is very difficult to have sufficient spatial and temporal resolution to traditional monitoring techniques,therefore the millimeter level of TS-DInSAR(Time Series Differential Interferometric Synthetic Aperture Radar)technology is applied to monitor damage of seasonal frozen soil to railways,which is very necessary to obtain characteristics and laws of the temporal and spatial distribution of influences along the railway.Therefore,one operating railway in Heilongjiang where seasonally frozen soil is commonly developed is selected as the research object,and according to the topographic and geological characteristics of the area along the railway,the targeted selection method and the TS-DInSAR error correction and calculation based on multi-master image interference are adopted,and using the time baseline for up to two years(September 2017 to July 2019)and high time density of 48 scenes of medium resolution Sentinel-1A SAR images,to obtain the subsidence of the area along the operating railway from the automatic joint test to the current operation Through the joint analysis with the time of freezing and thawing of the area,the temporal and spatial distribution law of the influence of frozen soil frost heave and thawing settlement on the settlement of the area along the railway has been learned,and it can provide reference data for the temporal and spatial evolution of seasonal frozen soil.