Abstract: Good gradation is required for the filling material of concrete face rock-fill dam in order to ensure good compaction and drainage. Taking the rock-fill material quarrying at Houziyan hydropower station on Dadu river as a research background, we summarize 6 groups of field blasting test in Selonggou quarry, and analyze the main factors affecting the rock-fill material gradation based on different blasting designs and screening results. Research results show that the gradation is affected by spacing between blasting holes, length of stem blocking, and unit consumption of detonator. Before large-scale stone quarrying, blasting tests should be conducted for each impact factor in order to determine the optimal blasting parameters. Through the field blasting tests, blasting scheme and parameters that can be used to get eligible rock-fill material are obtained, and the achievements in this research can be guidance and reference for similar projects.

Key words: Houziyan hydropower station, rock-fill dam, blasting test, drilling and blasting parameters, gradation