Parameterized Study on Gas Distribution Law at the Secondary Lining Trolley
In order to study the distribution of gas under the influence of different factors before and after the tunnel trolley,the fluid mechanics software Fluent was used to establish a press-in ventilation calculation model to study the influence of the outlet velocity of the air duct,the lateral and longitudinal positions of the gas release source,and the retardation coefficient of the trolley on the distribution law of the gas during the full-section construction.The results show that the greater the air velocity at the outlet of the duct,the stronger the dilution effect on the gas.When the gas source is on the opposite side of the air duct,the dilution effect of the wind flow on the gas is the strongest,and when the gas release source is located at the vault,the dilution effect of the wind flow on the gas is the weakest.The closer the gas release source is to the longitudinal position of the air duct,the lower the maximum gas concentration.The area of the tunnel trolley will affect the distribution of gas concentration in the tunnel,and the larger the trolley area,the smaller the peak gas concentration.In the actual construction,the air speed of the outlet of the duct should be increased as much as possible.The release position of the gas release source should be paid attention to and reasonably carry out construction ventilation.At the same time,the gas concentration in front of the tunnel trolley should be paid attention to,because gas accumulation is more likely to occur here.
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