Abstract
Building utility tunnels has been widely adopted as an important solution for the sustainable development of cities, but their unique fire problems have not attracted enough attention to date. With the purpose of preliminarily understanding the fire phenomena in a utility tunnel, this study performed a comprehensive analysis, including the burning behaviour of accommodated cables, hot gas temperature field and enhanced fuel burning rates based on bench-scale, full-scale and model-scale fire tests. The critical exposed radiative heat flux for the 10-kV power cable to achieve complete burning was identified. The whole burning process was divided into five phases. The cable’s noteworthy hazards and dangerous fire behaviours were also examined. The two-dimensional (2D) gas temperature fields and longitudinal maximum temperature distributions were investigated carefully, after which a versatile model was derived. The model predicted the maximum temperature attenuation of both upstream and downstream flows reasonably well. Finally, the phenomenon of enhanced fuel burning was explored. A multivariate cubic function that considers the global effects of relative width, height and distance was further proposed to estimate the enhancement coefficient. The current findings can provide designers and operators with valuable guidance for the integrated promotion of utility tunnels’ fire safety level.
Highlights
Urban utility tunnels are joint-use underground passages for accommodating multiple utilities such as water, sewerage, gas, electrical power, telephone and heat supply
Would lead to a much higher heat release rate compared with the similar fuel burning in an open space
Carvel et al [18] made a comprehensive review of documented tunnel fire tests, identified the most would lead to a much higher heat release rate compared with the similar fuel burning in an open space
Summary
Urban utility tunnels are joint-use underground passages for accommodating multiple utilities such as water, sewerage, gas, electrical power, telephone and heat supply. Changed in these studies, but this should be possible in scenarios as a fire can occur at a high position Another very hazardous phenomenon should be noted—the same fuel burning in tunnels on the cable tray. Carvel et al [18] made a comprehensive review of documented tunnel fire tests, identified the most would lead to a much higher heat release rate compared with the similar fuel burning in an open space. Bench-scale tests to inspect the burning behaviour of cables, full-scale tests to investigate the gas temperature field and model-scale tests to examine the enhanced burning rate of fuels were all performed, with the purpose being to preliminarily understand the fire phenomena in. This research can provide designers and operators with valuable guidance for the promotion of utility tunnels’ fire safety level, in order to guarantee a sustainable future. Integrated promotion of utility tunnels’ fire safety level, in order to guarantee a sustainable future
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