向家坝坝基排水孔涌水量控制标准研究

为实时监控坝基的渗透安全性,向家坝水电工程采用了坝基扬压力和涌水量可实时调控的坝基渗流自动化控制系统。排水孔涌水量控制标准是系统运行的关键指标之一。在对左非3坝段坝基渗流实测资料分析的基础上,采用渗流数值分析方法全面研究了左非3坝基扬压力和水力梯度分布特点,获得了坝基排水孔出流控制涌水量与孔口控制压力之间变化关系。依据排水孔控制涌水量与控制孔口压力之间的函数关系,结合坝基扬压力设计值和控制水力坡降的要求,提出了向家坝坝基可控抽排系统涌水量标准,并成功应用于工程实践中,取得了预期效果。

Control criterion of water inrush for drainage hole in the base of Xiangjiaba Gravity Dam

To monitor the safety related to seepage of the dam foundation, a real-time automatic control system was employed for adjustment of uplift pressure and water inrush in the dam base of Xiangjiaba hydro-power engineering. The controlling criterion of water inrush of the drainage hole is one of the most important indices for the operation of the system. Based on the analysis of the measured data of dam foundation seepage status, numerical method of seepage analysis was employed for the research of distribution of the uplift pressure and hydraulic gradient in the foundation of NO.3 dam section. Relationship between water intrusion and water pressure at the outlet of the drainage hole was also obtained. According to the above relationship, combination with the request of design value of uplift pressure and controlling hydraulic gradient of the dam foundation, a control criterion of discharge of drainage hole for the seepage controlling system of Xiangjiaba hydro-power engineering was proposed. The research results were applied in the operation successfully and achieved the desired purpose.