碾盘山水利水电枢纽泄水闸坝段防渗墙下部岩体为泥质粉砂岩、粉砂岩、中粗砂岩、含砾中粗砂岩等(K₂P^3-1),为中等透水红砂岩,水泥灌浆吸浆量小,灌后透水率仍普遍大于10 Lu,处理效果不理想。为了解决该问题,根据以往工程经验,采用丙烯酸盐化学灌浆进行处理,开展经室内岩样有压、无压可灌性试验和现场化学灌浆试验。结果表明:CW520丙烯酸盐灌浆材料对帷幕红砂岩具有良好可灌性;控制丙烯酸盐灌浆材料的浆液胶凝时间为35~45 min,定量灌注量为80 kg/m时,既可达到工程设计防渗要求,又能有效控制灌浆量,节约工程投资。研究成果已成功应用于碾盘山水利水电枢纽主体工程防渗帷幕灌浆设计与施工。

The rock mass under the impervious wall of Nianpanshan Water Conservancy and Hydropower Project is moderately permeable red sandstone containing argillaceous siltstone, siltstone, medium coarse sandstone, and gravel-containing medium coarse sandstone (K₂P^3-1), etc. As the rock mass absorbs a small amount of slurry, cement grouting has unsatisfactory result with the water permeability after grouting still over 10 Lu. To tackle this problem, according to previous engineering experiences, we adopted acrylic chemical grouting and carried out indoor pressurized and pressureless groutability tests of rock samples and on-site chemical grouting tests. Test results demonstrate that the CW520 acrylate grouting material has good groutability for the red sandstone curtain. When the grout gelling time of the acrylate grouting material is controlled within 35-45 min and the unit grout consumption is 80 kg/m, the anti-seepage requirements of project design can be met, the grouting amount can be effectively controlled, and the project cost can be cut. The research findings have been applied to the design and construction of anti-seepage curtain grouting for the main works of Nianpanshan Water Conservancy and Hydropower Project.