西安市典型区地面沉降时空演化特征研究

Spatiotemporal evolution characteristics of land subsidence in typical areas of Xi’an city

针对西安地面沉降长期发育发展严重制约着城市基础设施建设、文物遗址保护和人身财产安全的问题,该文采用SBAS-InSAR技术对2018—2021年间覆盖西安市区的35景Sentinel-1A影像数据进行处理,并结合小波变换方法探究西安主城区及典型区域的地面沉降时空演化特征。结果表明:①InSAR地面沉降监测结果与几何水准测量值之间差值均介于±3 mm内,InSAR监测结果真实可靠;②西安地面沉降空间分布整体上与地裂缝、断裂走向高度相关,地面沉降速率最大值位于航天城为67.98 mm/a,历史沉降中心鱼化寨和电子城附近均出现明显地面回弹,回弹量超过40 mm的区域面积达2.78 km^(2);③地面沉降在时间尺度上受不同大小的多层次周期变化所控制,在周期时间尺度下存在着影响沉降发育趋势的局部小周期。西安地面沉降发育与地下水开采、断裂和地裂缝发育、建筑载荷及地铁施工建设有关,研究成果为城市建设规划、地下空间资源合理配置和地下水资源保护等提供支持。

In response to the serious threat posed by the development of land subsidence in the Xi'an region to urban infrastructure construction,cultural relic protection,and the safety of personal and property,this article uses SBAS-InSAR technology to process 35 Sentinel-1A image data covering the urban area of Xi'an from 2018 to 2021,and combines wavelet transform analysis to explore the spatiotemporal evolution characteristics of land subsidence in the main urban area and typical areas of Xi'an.The results show that:①The difference between InSAR ground subsidence monitoring results and geometric levelling values is within±3 mm,and the InSAR monitoring results are true and reliable;②The overall spatial distribution of ground subsidence in Xi'an is highly correlated with the strike of ground fissures and faults.The maximum ground subsidence rate is 67.98 mm/a in the Hangtiancheng,and there is significant ground rebound near the historical subsidence centers of Yuhuazhai and Dianzicheng.The area with a rebound amount exceeding 40 mm covers an area of 2.78 km^(2);③Land subsidence is controlled by multi-level periodic changes of different sizes on a time scale,and there are local small cycles that affect the development trend of subsidence on the time scale of periodic changes.The development of ground subsidence in Xi'an is related to groundwater exploitation,fracture and fissure development,building load,and subway construction.The research results provide support for urban construction planning,rational allocation of underground space resources,and groundwater resource protection.