Abstract:

 Orifice pipe seal may leak water and orifice pipe may fall off at high water pressure in the previous drilling process, and the previous drilling and broken pipe treatment is with high risk and low efficiency. To solve these problems, first, a new process of orifice pipe sealing using epoxy resin bonding materials instead of cement slurry and hemp wire is proposed, which can increase the sealing and enhance the adhesion; second, the rationality of the number of expansion bolted orifice pipe using 6 groups of specifications M12 is analyzed,and an emergency device of drilling and broken pipe is proposed; finally, the predrilling test and the practical application of the drilling process are carried out. The results show that: (1) the orifice pipe and the tunnel segment have a good sealing effect and firm bonding during the test; (2) no water leakage or shedding occurred during the drilling practice process; (3) in practical application,the pipe breaking emergency device can quickly deal with the water leakage and sand gushing in the broken pipe, and the drilling rig can be quickly put into the next hole, which improves the drilling efficiency and reduces the processing risk.

Key words: underwater, frozen drilling, water leakage and sand gushing, risk prevention and control, shield tunnel