Model test on frost heaving pressure induced by frozen partial ponding behind tunnel lining in cold region

For tunnels in a cold region, the research of frost heaving-induced pressure (FHIP) due to frozen partial ponding is carried out based on certain theoretical assumptions. However, there is few research using the laboratory experiment to investigate the evolution of FHIP with time and space. Therefore, in this paper, to study the mechanism of the FHIP induced by frozen partial ponding of tunnel in the cold region, a three-dimensional geotechnical model test equipment only considering frost heave loads on lining is developed, in which the cold air of environment can be blown into the tunnel. Accordingly, the variation law of FHIP and the temperature field in the surrounding rock under the freezing condition are discussed. Moreover, a three-dimensional cone shape constrained model is developed to predict FHIP by considering the differences of the ponding depth, the stiffness of the surrounding rock and lining, which is further validated by comparing with experimental data. Results indicate that when the FHIP occurs, the temperature in the surrounding rock starts to drop rapidly with time. This proposed model can evaluate the FHIP caused by a frozen partial ponding with any cone shape and size. To account for the effect of time, the theoretical and semi-empirical model is further developed based on the three-dimensional cone shape constrained model. Comparisons with experimental data demonstrate that the modified theoretical and semi-empirical model well predict the evolution law of FHIP. This research can provide theoretical references to reveal the spatio-temporal evolution of the FHIP for partial ponding of tunnels in the cold region.