融合时序InSAR和LiDAR技术的海岛地铁沿线地面形变分析

Ground deformation analysis along island subway line by fusing time-series InSAR and LiDAR techniques

为了解决地铁建设和运营阶段会对地面造成不同程度的影响,特别是海岛建设地铁,其地形地貌环境复杂,土层不稳定,地面形变研究困难等问题。基于哨兵-1的38景影像数据和自主采集的隧道点云数据,采用永久散射体合成孔径雷达测量技术、差分干涉测量短基线集时序分析技术和激光雷达技术对厦门岛范围内的地铁2号线沿线区域进行研究。将合成孔径雷达的两种技术结果进行精度对比,并与水准数据进行比较,验证其准确性,最后结合激光雷达技术对该地铁内部隧道扫描获取点云数据进行形变结果对比。实验表明,PS-InSAR技术形变速率在-24.21~24.19 mm/y之间,而基于SBAS-InSAR技术的形变速率则在-22.86~33.79 mm/y,两种方法在形变监测过程中表现基本一致;与水准测量结果对比得到二者之间存在一定误差,误差集中在±7 mm以内,部分与水准点距离较远的误差在13 mm左右;而地下隧道沉降在-43.4~104.1 mm之间,中误差为28.44 mm,其结果与地面形变差异巨大。经过多次验证得知地下轨道交通隧道受到地面形变的影响较小。

The construction and operation of subways causes different degrees of impact on the ground,particularly the construction of subways on islands,which have complex topographic and geomorphologi-cal environments,unstable soil layers,and ground deformation that is difficult to analyze.The objective of this study was to solve these problems.In this study,using the 38-view image data of Sentinel-1 and tun-nel point-cloud data collected independently,the permanent scatterer synthetic aperture radar measure-ment technology,differential interferometry short baseline set time-series analysis technology,and Li-DAR technology were employed to study the area along Metro Line 2 within Xiamen Island.The accuracy of the results of these two techniques based on synthetic aperture radar were compared with level data to verify their accuracy.Finally,the results of deformation were compared with the results of the LiDAR technique to obtain point-cloud data by scanning the tunnel inside the subway.The experimental results show that the deformation rate based on PS-InSAR technology ranged from-24.21 to 24.19 mm/y,whereas the deformation rate based on SBAS-InSAR technology ranged from-22.86 to 33.79 mm/y;the two methods were essentially identical in the process of deformation monitoring.The comparison with the level measurement results indicate that there was an error between the two.The error was concentrat-ed within±7 mm and was approximately 13 mm for some of the distances from the level.Meanwhile,the settlement range of the underground tunnel was-43.4 to 104.1 mm,with a medium error of 28.44 mm,and the result differed significantly from those for the ground deformation.After several verifications,it was confirmed that the underground rail transit tunnel is less affected by the ground deformation.