孟加拉帕德玛大桥独立测量坐标系统技术研究

Establishment of Independent Survey Coordinate System of Padma Bridge in Bangladesh

孟加拉帕德玛大桥主桥共41孔,每孔跨度150m,全长6 150m。该桥业主提供的控制网坐标系统采用UTM投影,且桥位区远离中央子午线,投影变形巨大,导致控制网无法满足大桥施工要求。为了消除投影变形,对该桥坐标系统变形原因进行了详细的理论分析及实地验证,针对存在的坐标系统问题提出解决方案:以高斯投影为基础,选取桥位区平均经度90°10′为中央子午线,选择平均施工高程面37m为投影高程面,建立的桥梁施工独立测量坐标系统,很好地消除了控制网坐标系统的变形,满足帕德玛大桥施工精度要求,保证了大桥顺利施工。

The main bridge of the Padma Multipurpose Bridge has a full length of 6 150 m,arranged in 41 spans,each 150 m.The coordinate system of the control network provided by the owner adopts the UTM projection,and the bridge site is far away from the central meridian,the projection is subjected to experience great deformation,as a result,the control network could not meet the construction requirements of the bridge.To eliminate the projection deformation,the deformation causes of the coordinate system were theoretically analyzed and practically verified in detail,and solutions were proposed in light of the problems in the coordinate system.The results demonstrate that it is better to take the average longitude of 90°10′at the bridge site as the central meridian based on the Gauss Projection.If the average construction elevation of 37 mis taken as the projection elevation to establish the independent survey coordinate system of the bridge,the deformation of the coordinate system of the control network would be eliminated to a satisfactory degree.The controlling results meet the precision requirements of the Padma Bridge,which ensure the smooth progress of the bridge construction.