基于SBAS-InSAR的矿区地表沉降监测与分析

Monitoring and Analysis of Surface Subsidence in Mining Area Based on SBAS-InSAR

针对雷达差分干涉测量技术(differential interferometry synthetic aperture radar,DInSAR)易受时空失相关、大气相位延迟等因素的影响,采用小基线集技术(small baseline subset,SBAS)对13景TerraSAR-X数据进行时序处理,估算并去除了残余数字高程模型误差、大气延迟误差和轨道误差,分析了研究区域2012-2013年沉降速率,发现2310和1301两工作面最大下沉速率分别为40mm/a和50mm/a;分析时序累计沉降值发现,2306、2308、2310这3个工作面在2012年11月15日之前地面沉降并不明显;在2310和1301工作面分别提取3个失相干现象表现较为缓慢的候选点进行时序分析,发现沉降值和时间成线性变化关系,且开采时间越早,其沉降特性越符合线性变化;将SBAS和DInSAR两种方法获得的累计沉降值进行差值分析,发现两种方法的差值在5mm以内;在2310工作面走向方向和倾向方向选取若干观测点,并提取各观测点的时序沉降值对工作面时序沉降进行量化分析,实验表明SBAS-InSAR技术在矿区地表沉降监测与分析方面具有良好的应用前景。

DInSAR technique is easily influenced by decorrelation of time and space and atmosphere delay,SBAS(small baseline subset technique)was applied to process 13 scene of TerraSAR-X data.The residual DEM error,atmospheric delay error and orbit error are estimated and removed.The maximum subsidence rates of 2310 and 1301 working faces were 40 mm/a and 50 mm/a respectively by analyzing the subsidence rate of the coal mine area from 2012 to 2013.It found that the land subsidence of 2306,2308,2310 working faces is not obvious before November 15,2012 by analyzing the timing cumulative subsidence map.Three candidate points of slowly decorrelation filter phase in the 2310 and the 1301 working faces were extracted respectively to be analyzed and we found that the relationship between sedimentation value and time was linear,moreover,the earlier the mining time was,the more the linear variation of the sedimentation characteristics was.Cumulative settlement values obtained by the SBAS and DInSAR were compared and analyzed and turned out that the difference between the two methods was less than 5 mm.The time sequence subsidences of several points in the trending and orientation of 2310 working face were selected and extracted,the surface subsidence of study area in different time period was quantitative analysis by analyzing the displacements of these points.Experiments show that SBAS-InSAR technology has a good application prospect in the monitoring and analysis of surface subsidence in mining area.