短线法节段预制桥梁几何线形控制的坐标变换方法研究

Study on Coordinate Transformation for Geometry Control of Precast Segmental Bridge with Short-line Method

为保证节段预制桥梁运用短线匹配法施工过程中的几何线形控制精度,针对现有坐标转换方法在节段预制桥梁线形控制中存在的不足,构建了7参数坐标转换模型进行节段坐标变换,并详细推导该模型的非线性最小二乘求解过程。根据平差处理结果进行节段位置的误差分析,进而指导后续的节段纠偏过程,保证拼装后的线形精度满足设计和施工要求。为验证该方法的正确性和有效性,在郑许市域铁路许昌段工程中应用该坐标变换方法进行节段预制桥梁的几何线形控制,选取直线段和曲线段桥梁进行坐标变换对比分析。实验结果表明,提出的基于非线性最小二乘的坐标变换方法比现有Bursa模型方法精度更高,能够满足实际工程中线形控制精度要求,并能适用于各类型的桥梁线形控制。

In order to ensure the spatial accuracy of the geometry control of precast segmental bridge with short-line method,a 7-parameters coordinate transformation model is constructed to perform the coordinate transformation of precast segmental bridge.In view of the shortcomings of the existing coordinate transformation methods in the geometry control of precast segmental bridge,the non-linear least squares solution process of the model is deduced in detail.Furthermore,error analysis is performed according to the adjustment results,and then the subsequent segment correction processing is guided to ensure that the geometry line type meets the precision control of bridge design and construction requirements.In order to verify the correctness and effectiveness of the proposed method,the coordinate transformation method in this paper is used in the geometry control in Xuchang section of the Zhengzhou-Xuchang Railway.Experiments on both straight bridge and curved bridge are conducted.The experimental results show that the proposed coordinate transformation method has higher accuracy than the existing Bursa method,meets the accuracy requirements of the geometry control of precast segmental bridge and is suitable for various types of bridges.