SBAS Ground-based Technology In The Beijing Area Settlement Monitoring And Analysis

Contraposing the practical status of BeiJing land subsidence,Useing the SBAS technique monitor the subsidence of Beijing city from9and35ENVISAT ASAR images during2006to2010. And get the long time series of the monitoring results in the study area.Prepare the two result which got from Interpolation with the GPS results and the accumulated settlement contours, found that they have good consistency in space and time, the maximum error was less than10mm, then Proved the reliability of the technology,also proved that monitor accuracy of the technology to reached millimeter level. Then prepare the SBAS result which get from the only9SAR images with it get from35SAR images,then found the two result was very close.proved that the SBAS technology can obtain good experimental results when only use finite data set.Analyzing the rule of the spatiotemporal distribution and annual change of surface deformation.Through the experiment,The Chaoyang east,and the adjacent area of Chaoyang and tongzhou have obvious subsidence trend.from2006to2010.on the whole,the west of East three rings have slight subsidence,the subsidence of Chaoyang,Shunyi is serious.The scattered slices of subsidence area were expanded to lager Planar area,and the planar area have non-uniform settlements The subsidence center area is funnel-shaped.the subsidence area expand in NE-SW extension area.In addition, this paper summarizes the causes of land subsidence.With the increasing of underground water over withdrawing, regional ground subsidence funnels will be expanded,reflecting the extraction of groundwater as the main reason leading to land subsidence. The subsidence funnels is consistent with depression cone of groundwater level. the ground subsidence in time series has a clear seasonal variation and also depends on the impact of faults, ground loads and so on.