Seismic Isolation Simulation of Pipeline in Utility Tunnel

Utility tunnel (UT) is an underground tunnel structure that carries more than two types of public utility lines, like pipeline and cable. Before 1970s, Utility tunnel had been considered to be a low seismic risk, however, in recent decades, UT have been found to be often damaged under strong earthquake motion and large ground displacement, and the pipeline system contained in utility tunnel was also observed damaged in earthquake, such as broken, tensile and torsion in joints, and dropping from its bear or anchor ring. Based on shaking table test and numerical simulation, this paper presents seismic isolation equipment for reducing seismic response of pipeline, and several parameters including the device stiffness and its damping, geometric size and layout related to seismic isolation effect are discussed by use of finite element analysis. It is proved that this device can make a 50~60 percent cut down for seismic response of pipeline.