龙滩大坝真空激光准直系统工作基点改造方案设计

Design of Measuring Base Point Transformation Scheme for the Vacuum Laser Collimation System in Longtan Dam

龙滩水电站大坝坝轴线采用折线形,共布设两套激光准直系统。因建设期种种原因,系统未能按相关规范要求设置工作基点,监测成果并不理想,未能充分发挥激光准直系统高精度的优越性。为此,提出在廊道内19号和20号、20号和21号坝段之间的横缝处各安装一支双向测缝计,将19号坝段的垂线坐标数据引至21号坝段;静力水准从32号坝段引向21号坝段、11号坝段引向5号坝段的改造、校核方案。建议与两套真空激光准直系统主体更换改造项目一起实施,从而提高费用效益比。

Two sets of laser collimation system are arranged in Longtan Hydropower Station to monitor the broken-line axis of dam, but the system fails to set measuring base points according to relevant specifications during construction period. The monitoring results are not satisfied and the advantages of high precision laser alignment system are failed to be fully play. The proposed transformation scheme includes that, （a） two two-way seam measuring devices will be installed in the horizontal joints of corridor between 19^th and 20^th monolith and 20^th and 21 ^st monolith respectively, and the vertical coordinate data in 19^th monolith will be transferred to 21^st monolith; （b） two static level systems will be transferred from 32^nd monolith to 21^st monolith and 1 l＇h monolith to 5th monolith respectively. In order to save cost, the transformation of measuring base points is proposed to be carrying out with the replacements of two vacuum laser collimation systems.