顾及季节性变形的GNSS高层建筑倾斜和沉降观测方法

Tilt and Settlement Monitoring of High-Rise Buildings Using GNSS Precise Point Positioning and Seasonal Ground Deformation

  • 摘要: 以北京华都中心深基坑开挖引起昆仑公寓的沉降和倾斜观测为例,详细介绍了采用GNSS(global navigation satellite system)精密单点定位技术(precise point positioning, PPP)对高层建筑的倾斜和沉降进行长期监测的方法。该方法包括以下4步:①采用PPP解算GNSS天线在全球参考框架(IGS08)中的地心地固(Earth-centered, Earth-fixed, ECEF)坐标(ECEF-XYZ);②将相对于全球参考框架的ECEF-XYZ坐标转换到一个区域性稳定参考框架, 即华北参考框架(NChina16)中;③在华北参考框架中将地心坐标转换为站心直角坐标(东西、南北和垂直3方向);④用华北地区季节性地面变形模型校正站心坐标位移时程,恢复建筑结构的真实位移(倾斜和沉降)。研究表明,在华北地区, PPP位移测量精度在水平方向上能够达到2~3 mm,在竖直方向上能够达到6~9 mm(24 h连续观测)。通过将PPP、NChina16与华北季节性地面变形模型相结合,可以实现对华北地区高层建筑和其他大型基础工程的准实时和长期静态变形监测,监测精度可达到毫米级。

     

    Abstract: This paper introduces a method which utilizes global navigation satellite system (GNSS) based precision point positioning (PPP) for conducting long-term tilt and settlement monitoring of high-rise buildings in North China. Two-year continuous GNSS observations from two high-rise buildings near a deep foundation pit in Beijing are used for the case study. The method comprises four steps: ① Calculating the geocentric coordinates (XYZ) of the GNSS antenna with respect to a global reference frame (e.g., IGS08) with the PPP method; ② transforming the geocentric coordinates to a regional reference frame-the North China reference frame (NChina16); ③ converting the geocentric XYZ coordinates to a station-centric East -North-Up (ENU) coordinates; ④ removing seasonal ground-surface deformation from the ENU time series and restoring the true displacements (tilt and settlement) of the building. Experimental result indicates that the PPP method is able to achieve 2-3 mm horizontal accuracy(root mean square error) and 6-9 mm vertical accuracy (root mean square error)for 24-hour continuous observations in North China. The combination of PPP, NChina16, and the North China seasonal ground deformation model can perform millimeter-accuracy, near-real time, and long term static structural health monitoring of high-rise buildings and other large-scale infrastructure projects in North China.

     

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