Failure Behavior of Tunnel Lining Caused by Concrete Cracking: A Case Study.

The cracks caused by fracture of concrete lining have adverse impacts on the tunnel structure, considering the influences of serviceability and durability. In this paper, a particular case study of a newly built tunnel structure is presented for a certain amount of longitudinal cracks, focusing on the inducement of cracking and effect of concrete fracture. An integrated field investigation is implemented to characterize the spatial distribution of longitudinal cracks and detailed site situations, and the temperature difference of concrete within the lining is as inducement according to a series of reliable experiments. To further understanding of the lining structure performance influenced by fracture behaviors, two groups of numerical models based on finite element software are simulated for reinforced concrete and concrete cross sections, respectively. Among the numerical models, a simplified crack model is applied for damaged lining structure, considering the realistic width and depth of cracks. Ultimately, different safety factors are adopted not only for verifying the stability of cracks but also for getting the differences of structural safety under maintenance work. Situations of crack are in accordance with the real conditions in situ, besides the maintenance work is proved as essential and effective methods in this damaged tunnel. [ABSTRACT FROM AUTHOR]