ABSTRACT
Tunnel excavated in low-permeability soil may experience large deformation and increase in lining load if water drains into the tunnel. Long-term dissipation of tunneling-induced excess pore pressure into the tunnel consolidates soil around tunnel with low permeability and imposes extra load on the lining. Meanwhile, seasonal temperature can also expand and shrink joint opening between rings and segments and alters the rate of water leakage into the tunnel. The lining deformation can increase under the incremental increase of consolidation load, but it might also show fluctuating pattern because of the seasonal temperature. In this study, combined effect of long-term consolidation load and seasonal temperature load on the joint opening are discussed. An empirical relationship between water discharge into the tunnel and the amount of joint opening is proposed using the field measurements data of an old tunnel. Then, the joint opening under the influence of both consolidation and temperature load are investigated using a soil-water coupled consolidation model and a thermal stress model. The numerical results show that by employment of these numerical models, the behavior of joints between rings can be simulates very close to those of measured ones.
