Abstract: The geological conditions of Xiangjiaba hydropower station is very complicated with a flexural core fracture 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 conducted 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 permeability 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.

Key words: flexural core fracture zone, cement-epoxy resin compound grouting, fatigue water pressure test, acoustic wave test, CW510 grouting materials