宜昌长江公路大桥主缆施工控制测量及营运监测

Construction Surveying and Monitoring for Main Cable of Yichang Changjiang River Bridge

分析大跨径悬索桥主缆线形测量的特殊要求和误差结构,介绍差分三角高程的测量原理和方法:首先以严格同步对向观测和跨越四边形的观测路线建立高精度跨河高程控制;再以差分方法削弱大气垂直折光的影响,提高单向三角高程测量的精度。该方法使主跨960m的宜昌长江公路大桥主缆相对垂度定位达到3mm(跨中1/2点)的水平。

This paper analyses special requirements and main errors of height survey for main cable of suspension bridge, and introduces the principle and means of differential trigonometric leveling. Fist, the precise vertical control network across the river is established by simultaneous reciprocal observation of trigonometric leveling and the observation's routes of spanning quadrilaterals. Second, the coefficient of vertical atmosphere refraction is determined by the vertical control network, and used to improve precision of single observation of trigonometric leveling. The method has been used in construction of Yichang Changjiang River Bridge successfully.