3D-FEM is applied to simulate the construction of parallel shield tunnels
and the laws of displacement
deformation and internal force of the old tunnel are analyzed along with the dynamic driving of the new one. In analyzing the interaction between shield machine and lining structure is taken into consideration in the model
as well as the transverse isotropy of lining structure. The results show that in the existent tunnel longitudinal nonuniform settlement and lateral displacement appear around the shield machine
and traverse torsion occurs behind the shield machine. The construction of new tunnel will apply the “lateral loading” effects to the old one
decrease the moment and increase the axial force in the traverse section
and make the internal force state of left and right sides to be not symmetrical any more. The longitudinal force-bearing state of the existent tunnel experiences a process of first compression followed by tension
and the most unfavorable stress state appears in its side far away from the new one. The thrust force
grouting pressure
and stratum loss
which should be controlled strictly
have great effects on the old tunnel; and the counterforce of thrust has a minor effect comparatively. This work offers references for the construction of similar engineering.