Application of Liquid Nitrogen Freezing Method on Sealing Water of Pipelining Formation in Inclined Shaft

In order to repair the gap of freezing curtain in pipelining formation of the inclined shaft, it put forward the scheme to freeze the pipelining gravel layer rapidly by using liquid nitrogen freezing technology based on the low temperature and high efficient principle of liquid nitrogen. Several measures were taken in this engineering to ensure the cross circle of freezing curtain in gravel layer, such as increasing the opening density of liquid nitrogen supply pipes in gravel layer and the flow of liquid nitrogen, decreasing the temperature of return air. The temperature data showed that the temperature of the 24 meters layer in NO.1 hole decreased to -31.3℃ after 110 hours positive freezing; the temperature of the 24 meters layer in Hole A₁ decreased to -10.3℃ after 160 hours positive freezing. After the end of the freezing, the water level kept invariant with pumping water underground.