复杂因素影响下的福州市地面沉降时空演化分析

SPATIOTEMPORAL EVOLUTION ANALYSIS OF LAND SUBSIDENCE IN FUZHOU CITY UNDER THE INFLUENCE OF COMPLEX FACTORS

地面沉降是福州市的主要地质灾害之一,自20世纪中期以来就有监测资料显示福州市存在地面沉降问题。本文基于永久散射体雷达干涉测量技术(IPTA),处理了福州市2008~2014年间多时相、高分辨率Terra SAR-X数据,对福州市6年时间的地面沉降进行监测分析,根据研究区地面沉降历史、建设发展现状及沉降异常区分布,着重分析了复杂因素影响下福州市地面沉降的时空变化规律。结果表明:福州市总体年均沉降率-15 mm·a-1左右,存在多个明显的快速沉降区;与1960~1990年的监测资料对比发现,沉降中心由地热温泉区向工程密集建设区转移;较大沉降区以快速线性沉降为主;地面沉降特征的变化受到多种复杂因素叠加影响,导致地面沉降空间扩张、速率加剧。该研究成果可为福州市或其他沿海城市地面沉降风险评估、地面沉降防控等提供一定的科学依据和参考。

Land subsidence is one of the major geological disasters in Fuzhou,south China. The land subsidence in Fuzhou was discovered by ground monitoring in the mid-20 th century. This paper uses the persistent scatterer interferometry(IPTA) to process the time series TerraSAR-X data from 2008 to 2014,and obtains the time series deformation in Fuzhou during this period,the history of urban land subsidence,the status of construction and the abnormal distribution of land subsidence in the study area. Then the spatiotemporal evolution of land subsidence is analyzed under the influence of these complex factors in Fuzhou City. The results suggest that the land subsidence is about 15 mm·a-1 in Fuzhou. There are many obvious rapid subsidence areas. The rapid subsidence area on the ground presents a new feature of space transfer. The subsidence center is transferred from the geothermal hot spring area to the engineering-intensive construction area comparing to the monitoring data from 1960 s to 1990 s. The large settlement area is dominated by rapid linear settlement. The variation of land subsidence characteristics is affected by the superposition of various complex factors,resulting in expansion of land subsidence space and increased subsidence rate. The research results can provide certain scientific basis and reference for land subsidence risk assessment and land subsidence prevention and control in Fuzhou or other coastal cities.