Abstract: To guarantee the safety of railway tunnel shafts under complex geological conditions, such as waterrich granite, highangle crack development, and highpressure water, modified ureaformaldehyde resin is used for watersealing grouting after test and scheme comparison when the grouting effect of cementbased materials, such as ordinary and ultrafine cement, cannot meet the construction requirements. The modified ureaformaldehyde resin is superior to ordinary and ultrafine cement regarding grouting volume, residual water in the grouting hole, and water leakage on the shaft wall. It can better guarantee the grouting effect and reduce the flooding risk of the shaft. The modified ureaformaldehyde resin can reduce the singlehole redrilling and regrouting time to improve the drilling and grouting effect. The modified ureaformaldehyde resin was applied in shaft #1 of the Gaoligongshan tunnel, and a favorable effect was achieved in watersealing grouting.

Key words:  railway tunnel; shaft, waterrich granite, water sealing grouting, modified ureaformaldehyde resin