(1. Engineering Research Center of Tunnel and Underground Engineering，Ministry of Education，Beijing Jiaotong University，Beijing 100044，China；2. Second Highway Consultants Co.，Ltd.，China Communications Construction Corporation，Wuhan，Hubei 430056，China；3. Research Centre of Geotechnical and Structural Engineering，Shandong University，Jinan，Shandong 250061，China；4. State Key Laboratory of Geomechanics and Geotechnical Engineering，Institute of Rock and Soil Mechanics， Chinese Academy of Sciences，Wuhan，Hubei 430071，China)
Abstract：Effective measures should be adopted to avoid geologic hazard such as collapse，water gushing and debris flow，when the drill and blast method is used to construct subsea tunnel. In the drill and blast method，the technical difficulty for engineering design and construction is how to ensure the safety of project when the tunnel passes through the fault zone. Combined with the characteristics of surrounding rock in Xiamen subsea tunnel，the grouting reinforcement，waterproof and drainage techniques are studied；and the related design schemes are proposed for tunnel passing through the fault zone with drill and blast method. According to the laboratory triaxial test results，the permeability of highly weathered granite is obtained. And the mechanical parameters of surrounding rock are obtained by back analysis. The distribution of external water pressure on lining of tunnel in weathered trough is obtained by numerical simulation. The achievements obtained in the research will benefit other subsea tunnels in practical engineering.
