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针对金川水电站工程区复杂的地质条件和渗控措施,分别建立基于排水孔等效模拟的坝基整体模型和基于密集排水孔“弃孔算法”精细模拟的左岸厂区子模型,采用Signorini型变分不等式和自适应罚函数相结合的稳定渗流分析方法对厂区围岩的长期渗控效应进行论证和敏感性分析。在数值模拟中,为了克服传统分析所采用的均质各向同性渗透系数不能反映裂隙岩体渗透特性的不足,首先根据两岸和坝基岩体优势裂隙组的空间展布情况,基于统计学方法初步确定其渗透系数张量并获得主值及主方向,再根据钻孔压水试验资料确定的等效渗透系数对其进行修正,并通过坝址区的地下水位反分析对该方法进行了验证。结果表明,运行期工况下防渗排水系统对山体地下水位具有控制作用,主变洞和发电机层底板处于自由面之上,厂房和调压室底板稍有承压性。帷幕的渗透特性、辅助排水孔幕以及排水孔间距对渗流场分布影响很小但能显著减小厂房洞室及排水廊道的渗漏量,因此应保证防渗帷幕的施工质量并建议设置辅助排水孔幕,建议中层廊道以下的排水孔间距设为3 m,中层廊道以上的排水孔间距放宽到4.5 m。
According to the complex geological conditions and infiltration control measures of Jinchuan Hydropower Station project area, a dam foundation model based on equivalent simulation of drainage holes and a left sub-plant model based on intensive drainage holes “abandon hole algorithm ” were established. Signorini type variation Inequality and adaptive penalty function of the combination of steady flow analysis method of plant surrounding rock long-term seepage control effect of demonstration and sensitivity analysis. In numerical simulation, in order to overcome the insufficiency of homogeneous permeability coefficient of permeability used in traditional analysis to reflect the seepage characteristics of fractured rock mass, based on the spatial distribution of dominant fractures of rock mass of both banks and dam foundation, based on statistical method Determine its permeability coefficient tensor and obtain the main value and main direction, then correct it according to the equivalent permeability coefficient determined by the pressure test data of drilling water, and validate the method by the backwater analysis of the groundwater level in dam site. The results show that the seepage-proof drainage system under the operating conditions has a control effect on the groundwater level of the mountain. The main tunnel and generator floor are above the free surface, and the floor of the plant and the surge chamber are slightly under pressure. The infiltration characteristics of curtains, the auxiliary drainage holes and the spacing of drainage holes have little effect on the distribution of seepage field, but can significantly reduce the seepage of the tunnels and drainage corridors. Therefore, the construction quality of anti-seepage curtains should be ensured and auxiliary facilities should be provided Drainage hole curtains, it is recommended that the spacing below the middle corridor drainage holes set to 3 m, drainage holes above the middle corridor to relax the spacing to 4.5 m.