基于虚拟投影中心的抽水蓄能电站施工测量坐标系建立

Establishment of Construction Measurement Coordinate System for Pumped Storage Power Stations basedon Virtual Projection Center

抽水蓄能电站工程区面积小、高差大,常规的抽水蓄能电站施工控制网,是选取枢纽工程平均高程附近的一个高程面建立的自由网。由于工程高差较大,常规方法只能保证部分枢纽区长度归算变形小于25 mm/km,无法保证所有枢纽区长度变形值满足规范要求。为解决长度归算变形超限问题,减少长度归算变形对工程施工测量精度的影响,通过对常规施工控制网坐标系长度变形的分析,提出了基于虚拟投影中心的抽水蓄能电站施工测量坐标系统建立方法。结果表明:该方法能有效消除或减弱控制网成果对输水发电系统贯通测量误差的影响,使勘测设计阶段成果与施工阶段得到有效衔接,可满足高差约640.00 m以内的抽水蓄能电站中长度归算变形不大于25 mm/km的要求,具有一定的推广价值。

The construction area of the pumped storage power station project is small and the height difference is large.The conventional construction control network of the pumped storage power station is a free network established by selecting an elevation plane near the average elevation of the key structures.Due to the large height difference of the project,conventional methods can only ensure that the calculated deformation of some key areas is smaller than 25 mm/km,and cannot guarantee that length deformation values of all key areas meet the specification requirements.To solve the problem of overrun of length calculation deformation and reduce the influence of length calculation deformation on the accuracy of engineering construction measurement,a method for establishing the construction measurement coordinate system of pumped storage power station based on virtual projection center is proposed by analyzing the length deformation of the coordinate system of conventional construction control network.The application results show that this method can effectively eliminate or alleviate the influence of control network results on the measurement errors of water transmission and power generation system,and effectively coordinate the results of the survey and design stage with the construction stage.Meanwhile,it can meet the requirement that the length reduction deformation of the pumped storage power station with a height difference of about 640.00 m is not exceeding 25 mm/km,and the method is of certain promotion value.