纳子峡面板砂砾石坝渗流性态三维有限元分析

根据纳子峡水电站工程坝址区地形地质条件,建立了坝址区三维渗流有限元模型,计算分析了正常蓄水、设计洪水和校核洪水3种工况下坝体及坝基的稳定渗流场,获得了坝体和坝基的位势分布、坝体各分区的渗透坡降及渗透流量等。计算结果表明,在各种工况下坝体及坝基的渗流场符合一般规律,混凝土面板及防渗帷幕等组成的防渗系统可消减水头84%以上,其作用明显;混凝土面板及坝基防渗帷幕的渗透坡降较大,垫层、砂砾料区等的渗透坡降很小,坝体各分区的渗透坡降均小于材料的容许渗透坡降,大坝防渗排水系统的设计在技术上是合理的。

Seepage Analysis for Sand-gravd Dam with Concrete Surface at Nazixia using Three-dimensional Finite Element Method

Based on the topographical and geological conditions of the sand-gravel dam at the Nazixia hydropower station,a three-dimensional finite element model is developed to simulate the seepage of the sand-gravel dam.This model is used to calculate the steady seepage fields of the dam and dam foundation under the three conditions of normal storage,design flood,and checked flood,to obtain the distributions of water potentials of the dam and dam foundation,and to acquire the seepage gradient and seepage discharge for each district of the dam.The results show that the seepage fields of the dam and dam foundation are as expected under different conditions,and the impervious system consisting of the concrete surface and impervious curtain has a significant effect by cutting down 84% of the water head.The concrete surface and impervious curtain have relatively higher seepage gradient than the cushion and sand-gravel.The seepage gradient of each dam district is under the allowable seepage gradient of the material,and the design of the seepage control and drainage system is technically reasonable.