Abstract: In order to study the law of main factors affecting the foundation joint of Xiluodu arch dam, the monitoring data of dam foundation joint are analyzed, and the specific mathematical expressions of components in effect quantity such as water pressure, temperature and time effect are constructed. Based on this, the safety monitoring statistical model for single measuring point is proposed. Results from the statistical model fit well with the measured values, which reasonably reflects the change trend of the opening of the foundation joints. At the same time, the confidence interval method is used to determine the safety monitoring index for foundation joint, which is used for early warning in the early stage of water storage. With the accumulation of monitoring data series and the change of boundary conditions, the safety monitoring model and monitoring index system will change. Therefore, it is necessary to modify them regularly based on the measured data to ensure the long-term safety and normal operation of the dam.

Key words: foundation joints, monitoring index, confidence interval method, Xiluodu arch da

摘要： 为研究影响溪洛渡拱坝坝基接缝的各主要因素的作用规律，对坝基接缝监测数据进行分析，构建效应量中水压、温度和时效等分量的具体数学表达式，据此提出监测效应量的单测点安全监控统计模型。统计模型结果与实测值拟合较好，能合理反映拱坝坝基接缝开合度的变化趋势。同时，采用置信区间法拟定坝基接缝的安全监控指标，用于蓄水初期的安全预警。随着监测资料系列的延长和边界条件的变化，安全监控模型和监控指标体系均会发生变化，应定期根据实测资料进行修正，确保大坝长期安全正常运行。

关键词: 坝基接缝, 监控指标, 置信区间法, 溪洛渡拱坝