Testing of Full-Scale Inflatable Plug for Flood Mitigation in Tunnels

The protection of high-risk underwater and underground assets, such as rail and road tunnels, is a high priority. Disasters and extraordinary events can significantly disrupt the functionality of such critical civil infrastructure. Events such as the 2012 flooding of New York City, when Hurricane Sandy caused seven subway tunnels and three vehicular tunnels to flood and remain inoperable for several days, have demonstrated the need for methods to mitigate vulnerabilities to or, at least, minimize the consequences of those events. Conventional emergency sealing systems are not always installed or operational during extraordinary events; this situation has prompted the investigation of alternative solutions, such as inflatable plugs capable of sealing off and protecting an underground system by stopping hazards. The development and testing of confined inflatable structures was performed at West Virginia University to verify the viability of flood containment with an inflatable plug in a tunnel section. The work was performed under the Resilient Tunnel project, which has progressed from the production of a proof of concept, air-inflated prototype to reduced and full-scale prototypes pressurized with water and subjected to back pressure for flooding simulations. This work summarizes the results of tests performed at full scale for the evaluation of the conformity of an inflatable plug to a typical tunnel section as well as the plug's ability to withstand simulated flooding and maintain axial stability. The tests comprised deployment, inflation, pressurization, and flooding simulation. The test results demonstrated that an inflatable plug could be installed and deployed and could seal a tunnel section by holding test pressures, while maintaining axial stability, with manageable levels of water leakage.