港珠澳大桥沉管隧道贯通测量方法

Method of Breakthrough Survey of Immersed Tube Tunnel of Hong Kong-Zhuhai-Macao Bridge

为了满足港珠澳大桥沉管隧道贯通测量的精度要求,管节在预制场制造完成后,标定其测量数据及坐标系转换参数,并计算管节沉放后的贯通特征点坐标。洞外定向边按照公路二等GPS观测,洞内导线网采用双车道双导线法,高程采用水准法引测至洞内贯通控制点。在贯通控制点设站,测量已沉管节贯通点GL1、GL8,以及管节首尾端姿态点L1、R1、L2、R2的三维坐标,并与贯通特征点标定成果进行比对。研究表明,估算洞内、洞外控制测量总横向贯通中误差为26. 4 mm,实测E24管节首端轴线偏北41. 7 mm(满足轴线偏差±100 mm要求),管节轴线、高程、坡度及姿态满足沉管隧道贯通测量精度要求。

In order to satisfy the accuracy requirement of breakthrough survey of immersed tube tunnel, the measuring data and coordinate system conversion parameters of the tube section are calibrated after being constructed in the fabrication yard, then the coordinates of breakthrough characteristic points of the immersed pipe are calculated The directed edges outside the tunnel are surveyed by GPS technical method in second- class highway GPS precision. The double-lane and double-traverse method is adopted for the inside traverse network. The elevation is surveyed by levelling method to transfixion control points inside the tunnel. The three-dimensional coordinates of the breakthrough points GL1, GL8 and attitude points L1, R1, L2 and R2 on the immersed tube section are measured at the breakthrough control points. The results are compared with the calibration coordinates of the characteristic points of the tube section. Study shows that the total horizontal breakthrough error caused by the control network inside and outside the tunnel is estimated to be 26.4 mm. The actual deviation of the head axis of tube section E24 is 41.7 mm to the north, which meets the requirement of the axis deviation of less than 100 mm. Pipe axis, elevation, slope and attitude all meet the accuracy requirements of breakthrough survey of immersed tube tunnel.