Abstract: The total mean square error of horizontal displacement monitoring on crest of Hunanzhen dam was larger than ±1.0 mm which is required in the Technical Specification for Concrete Dam Safety Monitoring. Thus, the combination of total station and adjustment-free prism with high precision as well as the minor angle method were adopted as renovation. After renovation, the largest total mean square error decreased to ±0.94 mm which met the requirement in the specification. The use of adjustment-free prism base for deformation monitoring with high precision is of advantages such as fast installation, high precision and low cost which is worthy of promotion.

Key words: Hunanzhen dam, horizontal displacement, minor angle method, adjustment-free prism base for deformation monitoring with high precision

摘要： 针对目前湖南镇大坝坝顶测点水平位移量全中误差不能满足DL/T 5178-2003《混凝土坝安全监测技术规范》规定的±1.0 mm技术要求的问题，提出高精度全站仪配合高精度免调节变形监测通用棱镜组采用小角度法进行水平位移监测的方案，通过该方案改造后，最弱点水平位移量全中误差降至±0.94 mm。该方案的成功实施可为类似工程提供参考，其中高精度免调节变形监测通用棱镜基座实现了变形监测现场棱镜的快速安装和调试，提高了安装精度和降低了成本，可在各种变形监测领域中使用棱镜作为观测目标的配套产品，以替代常规棱镜基座。

关键词: 湖南镇大坝, 水平位移, 小角度法, 高精度免调节变形监测通用棱镜基座