中文摘要：

针对西溪水库碾压混凝土重力坝运行中出现的坝基扬压力突然增大的渗流异常现象，首先对扬压力监测资料进行时空分析，初步得出坝基扬压力时段性骤升主要为持续高水位和温度下降基岩裂隙张开影响耦合作用所致，然后结合统计模型分析，进一步解析和验证异常坝基扬压力形成的物理成因，指出低温高水位的运行工况对大坝渗流较为不利，建议管理单位加强观测分析，条件许可时可对渗流异常部位采取灌浆、排水等渗流控制工程措施，以消除渗流隐患。

英文摘要：

Aimed at the seepage anomaly caused by the sudden rise of uplift pressure of dam foundation, which occurred in the operation of roller compacted concrete gravity dam of Xixi reservoir, this paper firstly makes a time-location analysis of the monitoring data of uplift pressure. It is preliminarily obtained that the sudden rise of uplift pressure of dam foundation in some time is mainly caused by the coupling effect which is affected the open of bedrock fracture under sustained high water level and temperature drop. Then, combined with statistical model analysis, physical causes of uplift pressure anomaly of dam foundation are further analyzed and verified. This paper points out that operating condition of low temperature and high water level is disadvantageous for dam seepage, advising management company to strengthen observation analysis and take engineering measures of seepage control such as grouting and drainage in order to remove the hidden seepage trouble if conditions permit.