特大型跨海桥梁工程似大地水准面精化实践与分析

Practice and analysis of quasi-geoid refinement in ultra-large sea-crossing bridge project

特大型跨海桥梁工程似大地水准面精化应用实践极少。为解决风浪大、长距离等复杂海况下海上施工的高精度定位和放样等难题,本文对某特大型跨海桥梁工程进行高精度似大地水准面精化,基于地形、重力数据等基础数据和先进的理论模型,采用应用广泛的第二类Helmert聚集法计算得到似大地水准面模型。经实践验证,该似大地水准面模型精度达±0.008 m,应用实测平均精度为±0.0118 m,成果满足设计精度要求;同时,通过将格网模型植入该桥梁建设所建立的工程用连续运行基准站(CORS)系统内,方便大桥日常建设中采用网络实时动态定位(RTK)实现高精度的施工放样,提高工作效率,为大桥顺利建设提供重要的基础技术支持和保障。

The application practice of quasi-geoid refinement in ultra-large cross-sea bridge projects is very rare.In order to solve the difficult problems of high-precision positioning and lofting for offshore construction under complex sea conditions such as high wind and waves and long distance,this paper carries out high-precision quasi-geoid precision for an ultra-large cross-sea bridge project.Based on basic data such as terrain and gravity data and advanced theoretical models,the second type of Helmert aggregation method,which is widely used,is used to calculate the quasi-geoid model.Through practice verification,the accuracy of the quasi-geoid model is±0.008 m,and the average accuracy of the applied measurement is±0.0118 m,which meets the design accuracy requirements.At the same time,by implanting the grid model into the engineering continuously operating reference station(CORS)system established for the bridge construction,it is convenient to use the network real-time kinematic positioning(RTK)in the daily construction of the bridge to achieve high-precision construction lofting,improve work efficiency,and provide important basic technical support and guarantee for the smooth construction of the bridge.