抽水蓄能电站输水及地下洞室系统渗流场三维有限元分析

Three-dimensional Finite Element Analysis of Seepage Field of Water Delivery and Underground Cavern System in Pumped Storage Power Station

抽水蓄能电站输水系统和地下厂房系统埋深较大,在上下库高水头差作用下,裂隙围岩渗流对工程建设安全和运行管理具有重要影响。依托牛首山抽水蓄能电站,采用三维渗流场有限元方法,建立包含输水系统、地下厂房系统和洞室围岩的三维渗流场数值计算模型,基于稳态渗流分析方法,在参数反演分析基础上,分析了抽水蓄能电站输水及地下洞室系统渗流场分布规律,讨论了上下库水位变化及厂房下游侧帷幕失效对渗流场的影响。结果表明:不同运行水位情况下,输水系统和地下厂房排水系统可以有效降低管道外水压力和厂房区浸润线位置,地下厂房大部分位于浸润线以上且渗流量在合理范围之内;厂房下游侧帷幕对减小厂房区渗流量具有明显的作用,对于地下水丰富且规模较大的地下洞室系统,有必要设置厂房下游侧帷幕。

The water delivery system and underground powerhouse of the pumped-storage power station are buried deep.Under the action of the high head difference between the upper and lower reservoirs,the seepage of the surrounding rock in the fissures has a significant impact on the safety of engineering construction and operation management.Based on the Niushoushan pumped-storage power station,this paper adopts the finite element method of the three-dimensional seepage field to establish a numerical calculation model of the three-dimensional seepage field consisting the water delivery system,the underground powerhouse and the surrounding rock of the cavern.Based on the steady-state seepage analysis method,and on the basis of the parameter inversion analysis,the distribution law of the seepage field of the water delivery and underground cavern system in the pumped-storage power station is studied.The results show that under different operating water levels,the water delivery system and underground powerhouse drainage system can effectively reduce the external water pressure of the pipeline and the level of the infiltration line in the powerhouse area.Most of the underground powerhouses are located above the infiltration line and the seepage flow is within a reasonable range;The grouting curtain at downstream side of the powerhouse has a significant effect on reducing the seepage flow.For the large-scale underground cavern system with abundant groundwater,it is necessary to set the curtain on the downstream side of the powerhouse.