Abstract: The problem of seismic stability of prefabricated utility tunnels can be caused by elevation differences in engineering sites. Hence, the software ABAQUS is used to develop a threedimensional finite element dynamic model to calculate straightline and brokenline utility tunnels. The seismic response of the structure and joint crack of utility tunnels, as well as the deformation, stress, acceleration, and failure characteristics of anchor bolt structures under seismic load and different lines of utility tunnels, are comparatively analyzed by studying the prefabricated underground utility tunnel on Weiyi Road in Xi′an, China. The following results are obtained. (1) The maximum horizontal displacement of the brokenline utility tunnel in x and z directions is near the bottom plates between the connection section of the shallowburied and deepburied sections, indicating that the connection section between sections with higher elevation and that with lower elevation is the deformation sensitive point. (2) The tension deformation of a joint crack of a brokenline utility tunnel during and after seismic is relatively small, whereas the horizontal and vertical sliding deformations are relatively large, with the horizontal sliding deformation being the largest. (3) Compared with the straightline utility tunnel, the failure value of the brokenline utility tunnel is greater, and the failure mainly occurs in the inclined section, most of which are tensile failures. In the actual design work, it is necessary to enhance the strength of the utility tunnel at the brokenline section.

Key words: different lines, prefabricated utility tunnel, seismic response, joint crack, anchor bolt, structural damage, numerical analysis