向家坝水电站挠曲核部破碎带水泥-环氧树脂复合灌浆试验研究

向家坝水电站坝址岩性岩相多变,地质条件非常复杂,坝右岸存在挠曲核部破碎带,对大坝的渗透稳定非常不利。现场施工发现水泥灌浆难以对坝基存在的挠曲核部破碎带进行有效处理,为解决挠曲核部破碎带地质缺陷,长江科学院在右岸二期基坑高程257 m平台进行了水泥-环氧树脂复合灌浆试验。灌后检查显示:透水率由复合灌浆前的平均透水率3.05 Lu降为0.075 Lu,做全压力为2.265 MPa的疲劳压水试验,经72 h透水率为0 Lu;水力破坏坡降比灌前提高了11.54倍;灌浆后平均波速比灌前提高16.8%。试验结果表明:湿磨细水泥-环氧树脂同孔复合灌浆的工艺是可行的,CW510环氧树脂灌浆材料能够浸润和渗透到挠曲核部破碎带不良地质体中,试验中所获得的工艺参数可以在向家坝水电站挠曲核部破碎处理中推广应用,并可为其他水工建筑物基础处理借鉴。

Cement-epoxy Resin Grouting Treatment for the Flexural Fracture Zone in Xiangjiaba Hydropower Station

The geological conditions of Xiangjiaba hydropower station is very complicated with a flexural core frac-ture zone at the right side of dam foundation,detrimental to the seepage stability of the dam.It’s hard to mend these geological defects such as siltstone and argillaceous siltstone with cement grouting .In view of this we conduc-ted test on platform at elevation 257m on the right bank of second-stage foundation pit using cement-epoxy resin grouting to mend the geological defects.The quality inspection results after grouting are as follows:water permea-bility reduced from 3.05 Lu to 0.075 Lu;the water permeability of fatigue water pressure test with full pressure of 2.265 MPa is 0 Lu after 72h;the gradient of hydraulic damage is 11.54 times higher than that before grouting;the average wave velocity improved by 16.8% over the previous grouting.The test results indicate that the treatment of cement-epoxy resin compound grouting for flexural core fracture zone in Xiangjiaba Dam is feasible,and could be used for reference by similar hydraulic structures with fracture zone.CW510 grouting materials could penetrate into the flexural core fracture zone.