PSI和CRI联合算法用于苏通大桥基础沉降监测

深厚河床覆盖层地基上建设的超大型群桩基础，其沉降是安全监控的关键问题。针对苏通大桥群桩基础沉降监测中存在的问题，在基础沉降监测中综合运用了永久散射体干涉测量（PSI）和人工角反射器干涉测量（CRI）监测技术。结合大桥自身的永久散射体特性和桥位区重点监测部位安装的人工角反射器，利用EV-InSAR软件的CTM模块对该地区2003－2008年（主体工程施工期间）间获取的20景Envisat卫星单视复数据（SLC）进行差分干涉测量处理，利用PSI和CRI联合算法成功提取出了桥位区的永久散射体点，并解算出各永久散射体点在施工过程不同阶段的变形量，客观、全面地反映了苏通大桥在建设过程中基础的沉降。将获取的主墩处的永久散射体沉降量与有限元计算结果进行了对比，两者相对误差为4.64%。研究结果表明，PSI和CRI联合算法是一种极具潜力的大型桥梁地基基础沉降监测技术。随着监测区合成孔径雷达（SAR）数据的不断累积，利用该技术可以不断获取运营中的苏通大桥基础的高精度沉降量。

PSI and CRI joint algorithm used to monitor settlements of Sutong bridge foundation

Settlement is the key point for safety monitoring of super-large pile group foundation built on thick bed overburden.According to the question existing in the settlement monitoring of pile group foundation in Sutong bridge,PSI(permanent scatterers interferometry) and CRI(corner reflectors interferometry) technologies are synthetically applied to the settlement monitoring for Sutong bridge foundation.Combining with the permanent scatterers characteristics of the bridge and corner reflectors set up in the key monitoring site at bridge region,by processing 20 scenes SLC(signal look complex) data of Envisat acquired in the construction period from 2003 to 2008,differential interferometry is analyzed by CTM module in EV-InSAR software.The permanent scatterers points in the bridge area are picked out and the deformations of the points in different construction periods are calculated by PSI and CRI joint algorithm.It reflects the settlement of Sutong bridge foundation in the construction process objectively and roundly.Comparing settlement values gained by PSI with finite element calculation,the relative error is 4.64%.The result indicates that PSI and CRI joint algorithm is a powerful technology to monitor the foundation settlement of huge bridge’s foundation.Along with continuous accumulation of SAR(synthetic aperture radar) data in the monitoring area,high-precision settlements of Sutong bridge foundation in operation period will be gradually obtained.