ANALYSIS AND EVALUATION OF SEGMENTAL CONCRETE TUNNEL LININGS - SEISMIC AND DURABILITY CONSIDERATIONS
Date of Award
2007
Degree Type
Thesis
Degree Name
Doctor of Philosophy
Program
Civil and Environmental Engineering
Supervisor
Dr. Sean Hinchberger
Second Advisor
Dr. K.Y. Lo
Abstract
Tunnels have been constructed by many civilizations, and over time, exciting new advancements in tunnelling techniques and methods have emerged. One such notable advancement is the tunnel boring machine (TBM), which facilitated the evolution of rapid excavation by shield driven tunnelling method. Precast segmental concrete tunnel linings are widely used in conjunction with the shield driven tunnelling method, and these linings have been implemented on numerous tunnelling projects during the second half of the 20th century. In some cases, long-term exposure of reinforced concrete linings to sulphates or chlorides in groundwater can lead to concrete deterioration and consequent reduction in the lining load carrying capacity. Engineers may thus be required to evaluate the distribution of moment and thrust in degraded liners to assess their factor of safety. Closed-form solutions can represent an attractive tool for such applications, especially if liner degradation is wide spread in a tunnel system of variable depth. This thesis presents a series of analytical solutions for analyzing tunnel linings in elastic ground. First, two closed-form solutions for composite tunnel linings are developed. The first solution considers the lining as an inner thin-walled shell and an outer thick-walled cylinder embedded in elastic ground and it accounts for the effect of ground convergence prior to installation of the lining (the gap). The second solution extends the first solution to account for the rotational stiffness of the tunnel’s joints for analysis of segmental concrete linings. Both solutions are shown to be useful analytical tools for assessing the moments and thrusts in degraded segmental concrete tunnel linings by applying them to study various tunnel problems. iii In addition, both composite solutions are adapted to permit calculation of in-plane stresses in tunnel lining induced by earthquakes. The composite lining solutions are then used to study the effect of local soil nonlinearity caused by an excavation damaged zone (EDZ) around bored tunnels (using the equivalent linear approach) during earthquakes. Finally, this thesis concludes by presenting the results of detailed numerical analysis involving the static and seismic response of tunnels with intact and degraded concrete liners. The analysis use both nonlinear methods and linear elastic closed form solutions to gain insight into the stresses in intact and degraded tunnel linings for both static and seismic loadings. In addition, the finite element results help to define limits for analysis of degraded linings using closed form linear elastic solutions.
Recommended Citation
ElNaggar, Hany, "ANALYSIS AND EVALUATION OF SEGMENTAL CONCRETE TUNNEL LININGS - SEISMIC AND DURABILITY CONSIDERATIONS" (2007). Digitized Theses. 4636.
https://ir.lib.uwo.ca/digitizedtheses/4636