Change And Driving Force Of Land Subsidence Analysis

Land subsidence is a kind of geological disasters, resulting from the decrease ofsurface elevation. It can threat the basic transportation facilities and urban majorbuildings. It requires effective monitoring methods to control and prevent landsubsidence and its hazards in the land subsidence area. The general land subsidencemonitoring system can provide high precision result; however, it has somedisadvantages, such as the high construction cost, the limited spatial coverage and thelow temporal resolution. The interferometirc synthetic aperture radar (InSAR) cancarry out high temporal and spatial resolution monitoring of land subsidence.The land subsidence in Tianjin mainly centralizes in the south plain. This paperfocuses on the Tianjin south plain, uses the atmospheric delay correction model basedoptimization PS algorithm. The paper chooses the mid-resolution Envisat-ASAR datato extraction subsidence information; analyzes the spatial distribution and revolutionaspects of land subsidence. There are three land subsidence funnel in the south plain,the subsidence area is large and the uneven subsidence mainly forms the Tianjin landsubsidence. In the Beijing-Tianjin railway area, the paper chooses the TerraSAR-Xdata to extract high resolution subsidence information. The area which static load islarge often suffers more serious subsidence, and the traffic line buffer area alsocontains more subsidence.By using the GIS-based spatial analyzes method, the paper analyzes therelationship between land subsidence field and underground water field, dynamic&static load field and geologic structure data. The paper finds that the land subsidencein Tianjin mainly affected by the deep groundwater funnel. Land subsidencecentralizes in the area where static&dynamic load are high. And the geologicstructure also controls the spatial distribution of land subsidence.