Study on Seismic Response of Segmented Utility Tunnels Crossing Ground Fissures

Taking the segmented utility tunnel crossing f5 ground fissures in Xi’an Xingfu forest belt as the research object, this paper investigates the acceleration response and the variation of displacement and stress of the segmented utility tunnel under the El-Centro seismic wave through 3D finite element simulation. The results show that under the orthogonal condition, the peak acceleration of foot wall soil is greater than that of hanging wall soil; conversely, under oblique loading, the hanging wall exhibits higher peak acceleration. In both loading conditions, the peak soil acceleration initially increases and then decreases with depth, while the amplification effect weakens as depth increases. Furthermore, the seismic response and deformation of the tunnel are more pronounced under oblique loading than under orthogonal loading. This study offers quantitative guidance for the seismic design of segmented utility tunnels crossing ground fissures.