Abstract
When the mountain tunnel projects passing through the complex formation with coal, it happened along with disaster accidents such as gas outburst, gas combustion, and gas explosion. These disasters should seriously threaten the safety and life of the construction personnel and affect the normal operation of the tunnel construction. Ventilation is the most effective means to control gas, fire, dust, heat, and other disasters. To study the effects of different ventilation modes in highway gas tunnels, Fluent software was used to simulate forced ventilation, exhaust ventilation, and mixed ventilation in a high gas tunnel of a highway in Hunan. The distribution law of the airflow velocity and gas concentration of these three ventilation modes were obtained to determine the optimal ventilation system. It was shown that vortex zones of different ranges formed in the tunnel for all three ventilation modes, and the gas concentration was higher in the vortex zone than in other regions. Mixed ventilation of them is superior to the other two modes, showing the best ventilation effect with regard to airflow velocity and gas concentration.
Highlights
Highway tunnel construction has expanded throughout China
In the mixed ventilation mode, the airflow is delivered from the forced air pipe and mixed with gas, and the rotation of velocity occurs on the tunnel face so that most of the mixed gas is sucked into the ventilation pipe by the suction region formed by the blower before being exhausted out of the tunnel
It can be seen from the airflow velocity vectors on the tunnel cross-section in Figure 4 that for all three ventilation modes, the airflow velocity is always greater at the ventilation pipe and continuously dissipates out of the boundaries, and vortex zones of different sizes are produced for each three modes
Summary
With urban construction development, numerous traffic tunnels have arisen in the mountainous and hilly areas of China [1–3]. A coal seam was exposed during the excavation process, consisting of pork liver coal and asphaltic coal These coals are tectonic coals, with high hardness and contain a large amount of gas with contents reaching 6.92 m3/t. Tunnel, effective measures of outburst prevention is necessary for penetration through the coal seam to suppress the gas concentration and gas pressure. This requires a scientific and rational configuration of the ventilation mode. The efficiency of tunnel ventilation was able to be enhanced, and the safety of the workers was guaranteed using the results of this research
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