Influence of lining permeability and temperature on long-term behavior of segmented tunnel
Wei Li, Alireza Afshani, Hirokazu Akagi, Shigeaki OKA
Abstract
The initial infiltration of ground water into tunnels excavated in soft clayey soils triggers the consolidation of the surrounding soil and imposes an extra load on the linings. This extra load may open the joints between rings and segments or intensify the deterioration of the joints. Relative soil-lining permeability, an important factor in the long-term behavior of tunnels, mainly depends on the condition and amount of joint opening between rings and segments. This study proposes a method for determining lining permeability based on the joint opening between rings only. The lining permeability value can be implemented and updated in coupled soil-water analyses during the entire consolidation process. In the final stages of consolidation, the values of the pore water pressure and water leakage reach a steady-state condition and the effect of seasonal temperature changes inside the tunnel becomes important. Furthermore, determination of the lining permeability under the influence of the temperature inside the tunnel is attempted. Long-term measured field data of an aged tunnel along with a coupled soil-water model are employed to verify and explain the long-term behavior of segmented tunnels using the proposed method. In addition, the applicability and limitations of the proposed method are presented and discussed.