Damage Analyses on Rock Cover of the Subsea Tunnel in Jointed Rock

Joints and Seepage pressure are considered as a positive factor for the damage of rock wall. Associating the damage mechanics, the constitutive model for the jointed roclanass under the seepage pressure is obtained under the conditions of compression-shearing and tension-shearing. The calculation method and finite element procedure come into being according to the above model. The program is applied to actual project to model the ground movements that occur when the subsea tunnel is installed in the jointed rockmass. According to the geological section, the subsea tunnel axes of nine sections selected are researched and analyzed. The paper applies the finite element procedure to analyze different cases of the sections through lifting and shifting the tunnel axis according to the thickness of bedrock. By analyzing their damage zones, plastic zones, stress state and displacement variation in all cases, the stability of the tunnel is studied. Based on the above analysis, the most appropriate tunnel axis position of every section is proposed.