An experimental approach to evaluating the long-term performance of segmental linings

There have been numerous engineering projects involving shallow buried metro tunnels underneath the subgrade of high-speed railways in China, and the metro tunnel inevitably bears the dynamic load induced by the high-speed trains above. Thus, the long-term performance of segmental linings cannot be negligible. An experimental model is an important method for evaluating the segmental linings. In the experiment, three key problems must be solved to ensure the strict similarity between the prototype and the model in terms of the structural form, initial earth pressure and fatigue behaviour of the segmental linings. A series of key points to maintain the similarity of the model is put forward, including the presentation of the standard joint-staggered model, the principle of a reserved displacement constraint device and the equivalence of fatigue life between the prototype and model materials. Based on similarity theory, a 1/10-scale model experiment is designed, and the stress and strain states are measured. The results show the model experimental design can be approximately consistent with the theoretical calculation and numerical simulation. The study provides a sufficient experimental basis for evaluating the long-term performance of segmental linings.