ANALYSIS ON STRUCTURAL RESPONSES OF PREFABRICATED CABLE TUNNELS WITH DIFFERENT JOINTS IN UNEVEN SUBSIDENCE

The longitudinal structural performances of the prefabricated cable tunnels in soft soil foundation in the cases of uneven subsidence were analyzed by the finite element mothod, which respectively have plain joints with prestressing tendons and tongue and groove joints with concave-convex faces and with or without prestressed tendons simultaneously. The vertical displacement, dislocation, opening width of joints, the stress and strain of the concrete, and the shearing forces in circumferential joints were analyzed and compared. It was shown that tongue and groove joints with concave-convex faces could improve the shear resistance of circumferential joints, prestressing tendons could improve the flexural resistance of circumferential joints. Both of them could improve the integrity of the prefabricated cable tunnels. But prestressing tension might result in larger opening width, dislocation and principal tensile stress in circumferential joints at tensioned segments. To avoid excessive deformation or local damage at circumferential joints, some design suggestions for prefabricated cable tunnels were proposed.