Response Of Tunnels Subjected To Seismic Conditions

📙 Tunnels are an integral part of the modern infrastructure used for subways, railways, highways and transport of water and sewage. Tunnels usually experience a lower rate of damage than the surface structures. However, some tunnels have experienced significant damage in large earthquakes, including the 1995 Kobe, Japan earthquake, the 1999 Chi-Chi, Taiwan earthquake and the 1999 Kocaeli, Turkey earthquake. The tunnel failures during earthquakes are mainly due to the lack in moment capacity of the tunnel lining. The tunnels which are subjected to earthquake activity must withstand both seismic and static loading. Prediction of actual strain that could develop in the tunnel lining due to ground deformation and the stresses during earthquakes constitutes one of the important aspects of seismic response analysis of tunnels. The objective of the present study is to carry out seismic response analysis of the tunnel considering variations in the surrounding soil medium, thickness of the lining and length of the tunnel. One numerical example involving circular tunnel is considered for the seismic analysis. Pseudostatic and time history analyses are carried out using finite element method.