Abstract：Based on engineering background of the Shanghai metro tunnel，the variation of joint rotating stiffness is analyzed by establishing a joint mechanics model which can describe any mechanical and deformative status under any group of loading on the joint，including moment，axial force and bolt prestressing force. The study shows that，for given dimension of joint，the rotating stiffness is the function of applied loading，and can be reduced by thinning the segment. This may be adverse to the performance of the loaded joint. But this situation can be improved by changing the position of linking bolt. The mechanical calculation demonstrates that decreasing the engineering cost and improving the performance of the joint can be achieved by adjusting the thickness of segment and the linking bolt position.
