Consequences of building a new tunnel on in-service tunnel: a review.

As the requirement for underground space is growing mainly in metropolitan cities, building a new underground tunnel in the locality of the in-service tunnel is one of the most common situation. Building a new tunnel might induce additional strain and stress modification resulting in damage to the in-service tunnel. This paper reviews from the research works conducted by earlier investigators on the subject matter under four categories, field monitoring, scale down modelling, numerical and theoretical approach. The purpose of this paper is to review recent developments and improve understanding of this issue. The drawbacks of each category and gray areas which need further investigation are presented in this paper. This review paper could facilitate the work of practising engineers and researchers by highlighting the problem and areas where requires further research. [ABSTRACT FROM AUTHOR]