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Vacuum tube transportation system is considered to be one of the most effective alternative transportation systems that can substitute the existing aviation system. Ensuring the airtightness of the vacuum tube system is therefore the most critical requirement of the infrastructure. This study proposes a model for airtightness performance evaluation of concrete vacuum tube structures with cracks. Several crack models are reviewed first and a simplified model for estimation of the total crack area is established. A hypothetical model that describes the pressure behavior inside a concrete vacuum tube subjected to cracks due to external loadings is developed. The model developed is expected to provide a basis for an experimental study to be performed in the near future. Based on both the experimental test and the analytical model developed, the relationship between the crack propagated in the concrete vacuum tube structures and its equivalent system air permeability is established.

Development of Air Inflow Model for Airtightness Performance Evaluation of Concrete Tube Structures with Cracks