Damaging behavior investigation of an operational tunnel structure induced by cavities around surrounding rocks

A case of damaging behavior in the concrete lining of an operational railway tunnel is studied and presented in this paper. The study focuses on the influence of tunnel structure damaging due to field observed construction deficiency of cavities around surrounding rocks, which is evaluated by means of field observation and numerical analysis. This work demonstrates that the construction deficiency of cavities around surrounding rocks plays an important role in the stability of tunnel structure, which can vary the stress state distribution of tunnel structure even with damaging behavior. Moreover, the implemented numerical analysis also demonstrates that the damaging behavior of tunnel structure induced by the field investigated cavities can be numerically simulated with taking account of the aforementioned cavities in the numerical model, which provides the design basis for appropriately strengthening the damaged tunnel structure.