Abstract: There is strict requirement on the ground water level in the construction of watersealing underground LPG storage caverns. There is great possibility that water loss may occur during shaft sinking by raiseboring method. Furthermore, it is difficult to perform grouting to stop the water inflow during shaft enlarging. The raiseboring method is determined to be used in the construction of Yantai watersealing underground LPG storage caverns on basis of hydrogeological borehole drilling and ground surface pregrouting. The type selection, working principle, working procedure and safety guarantee measures of raise boring machines are presented. In the end, the daily average shaft sinking speed reaches 2 m, the stability of the groundwater level is guaranteed, and safe, rapid and costeffective shaft sinking is realized.

Key words: vertical shaft, raiseboring method, underground watersealing cavern, raiseboring machine