基于NPSI方法的西安市地裂缝灾害链地表形变监测与演化态势分析

Earth Fissures and Land Subsidence in Xi’a n from NPSI Monitoring and Analysis

受构造背景、地下水采掘、活断层等因素的综合作用,西安市地裂缝于近年间不断加剧,引发多处不均匀地表沉降,并演化为对地表及地下建筑物均有强烈破坏作用的城市地质灾害链。为探明西安市地裂缝灾害链区域近年间的地表沉降态势、辨析不均匀沉降与地裂缝发育的联系,引入在城市地表形变监测精度和可靠性方面具有显著优势的网络化永久散射体时序雷达干涉测量(NPSI)方法,以2017年3月至2018年3月间成像的15期Sentinel-1A卫星SAR影像为数据源针对西安地区开展了时序监测分析,结合水准测量数据验证发现NPSI监测结果的精度达到±4.75 mm。实验结果表明:西安市地裂缝正向西南郊发育,地下水采掘及地上地下工程的建设在地裂缝发育趋势下加剧了不均匀沉降灾害,在形成地裂缝灾害链的鱼化寨、电子城、曲江新区以及地铁3号线等危害严重区域需要实时监测地裂缝发育趋势,并合理规划地下水开采及工程建设活动。相关研究结果可为路政、城建等部门的业务工作及相关研究提供参考信息。

Due to the combination of tectonic background,groundwater extraction,active faults and other fac⁃tors,the ground fissures in Xi'an have been intensified in recent years,causing many uneven surface subsidence.The urban geological hazard chain that has a strong destructive effect on underground buildings has attracted widespread attention from competent authorities and relevant experts.In order to infer the correlations between surface fissures and ground deformation,we use networked permanent scatterer Interferometric Synthetic Aper⁃ture Radar(NPSI)to characterize the land subsidence in Xi'an,which has significant advantages in the accuracy and reliability of urban surface deformation monitoring.In this study,we obtain 15 Sentinel-1A SAR image ac⁃quired covering the ground fissures in Xi'an between March 2017 and March 2018.Our InSAR observations were verified with leveling measurements,with an accuracy of±4.75 mm.The results show that the ground fis⁃sures are developing in the southwestern suburbs of Xi'an.Over-withdrawal of groundwater and the construc⁃tion of above-ground and underground facilities have exacerbated the trend of settlement and ground fissure de⁃velopment.Besides,the Yuhuazhai zones,Electicity Mall zones,Qujiang New District zones and the subway Line 3 need to monitor the development trend of ground fissures in real time,and rationally plan groundwater mining and engineering construction.This systematic research may serve as a reference for related research and for the operational departments of road administration and urban construction of the city.