Abstract: The high-pressure jet grouting pile is mainly suitable for the muddy soil, cohesive soil, silt, sand, loess and gravelly soil, but it is seldom used in the gravel stratum or under the dynamic water condition. A water cutoff certain in an open-pit coal mine was constructed by using RJP method, and the high pressure jet grouting technique was successfully applied to gravel aquifer. Based on the pile test and screening test, the influence of gravel layer characteristics on the size of pile diameter was analyzed. The results show that the RJP method had good effect and reliable quality in the gravel aquifer, and the pile diameter was related to the gravel particle size and sand content. Combined with the surrounding well test results, it was concluded that the curtain wall of high-pressure jet grouting pile was complete and had remarkable water cutoff effect. The research shows that the high pressure jet grouting technology could be applied in gravel aquifer for strata strengthening and water cutoff.