Design of a full-scale experimental blast tunnel Available to Purchase

In response to recent terrorist events, the UK government has sought to develop a means of examining the effects of explosive detonations within tunnel systems. A major component of this work has been the design and installation of a full-scale, instrumented, ‘superterranean' tunnel for the assessment of such blast effects on internal structures. Owing to the highly complex loading development, which results from such confined explosive detonations, it was decided that numerical techniques should be used as an integrated part of the design process. Hydrocode blast simulations were used to determine the spatial and temporal loading–time histories associated with charge initiation at critical locations within the tunnel. With emphasis on safe tunnel operation, these techniques were also used to estimate the pressure levels exiting the tunnel during testing. Explicit finite-element analyses were then used to assist in determining the optimal sizes and spacing of constituent structural components. Upon completion of the design, a series of initial proofing trials was conducted to confirm that the tunnel was fit for purpose; the facility has since been used to undertake specific tests associated with a variety of applications. This paper describes the philosophy behind the design of the facility, together with the mechanisms of dynamic response observed during the modelling process. A description of each analytical method is provided and emphasis is also placed on how modelling techniques were used to complement traditional civil engineering design and experience in producing a safe, fully functional, cost-effective facility.