A consolidation-perforation model for airtightness failure of filter cake during TBM hyperbaric intervention

With tunnel boring machines (TBMs) advancing into deeper and more complex ground conditions, hyperbaric intervention has become an indispensable but high-risk operation. The success of such interventions relies heavily on the formation and durability of an airtight filter cake at the tunnel face. However, under sustained air pressure, the filter cake undergoes compression and consolidation, which may eventually lead to perforation failure. The time-dependent nature of this process introduces significant uncertainty in predicting the duration of airtightness, posing operational and safety risks. To address this issue, this paper develops a consolidation–perforation model that captures both the increase in effective stress from consolidation and the localized shear failure of the filter cake. An airtightness test was conducted to validate the proposed model, and the results demonstrated good agreement with theoretical predictions. The findings provide quantitative insight into the failure evolution of filter cakes under air pressure and enable prediction of airtightness duration. This study offers guidance for safe hyperbaric interventions in TBM tunneling.