基于原型监测的广西乐滩电站大坝渗流特性分析

Analysis of Seepage Characteristics of Letan Hydropower Station

基于原型监测实测数据,采用时程曲线、分布图、特征值统计、相关分析、数学模型定量分析等方法相结合,对广西乐滩电站运行期大坝坝基扬压力的时空演化规律进行分析和评价。分析表明,扬压水位岸坡部位明显高于河床坝段,幕前测点高于幕后测点。帷幕后测点水位与下游水位高度正相关,下游水位是影响幕后测点扬压力变化的最主要因素,上游水位、温度、降雨和时效等因素影响均较小。综合分析认为,乐滩坝基扬压力测值变化平稳,幕后测点扬压折减系数未超出控制指标,幕后测点扬压力受上游库水位影响较小,说明上水库与坝基之间没有大规模的渗漏通道,坝基扬压力规律正常,大坝处于安全状态。

Based on prototype monitoring data, time-history curve, spatial distribution diagram, statistical analysis, correlation analysis and mathematical model analysis are integrated to study the seepage characteristics of the Letan dam. The results show that the uplift pressure before grout curtain is related to the upstream water level, and the uplift pressure after grout curtain is related to the downstream water level. The uplift pressure water level near the bank is much higher than which on bed. The uplift pressure water level before grout curtain is much higher than which after grout curtain. The uplift pressure coefficient is not beyond the control index, which indicate the waterproof and drainage system is in good condition. Downstream water level is the key factor to impact the uplift pressure after grout curtain. In conclusion, the temporal and spatial distribution of uplift pressure is interpre Tab.and normal, and the dam in safety.