An experimental study on the maintenance and repair of communication cable tunnels constructed by shield tunneling method

The current understanding is that aged deterioration poses a serious problem in the most of all communication cable tunnels that take an important role in information-oriented society. Lots of communication tunnels have been in existence for 30 years after construction, and there deteriorations by decrepitude have been coming to the surface. To use communication tunnels efficiently under this situation, suitable maintenance and repair are required. So, the establishment of the assessment method giving the correct strength diagnosis has become imperative. However, it remains to be elucidated how to evaluate soundness of tunnel appropriately in the limited funds and time. To establish the evaluation method, here we study structural performance of the tunnel itself and whether tunnel which a crack and corrosion generated can bear the purpose of use. In this study, we examined the degree of soundness about communication shield tunnels considering the main structural steel segment and also the secondary lining which is not expected its strength in the design. That is for the purpose of studying the practical and effective reinforcing method. Based on the perspective presented above, to establish analysis models about communication tunnels of various conditions, we confirmed each load bearing behavior of the steel segment and the secondary lining by seven experiments with a 1/2 scale models and numerical analyses. And the validity of an analysis model and the effect of the reinforcement construction method were investigated. The results of the study show the indicator of the maintenance management technique over the communication cable tunnels of various states.