二次衬砌台车处瓦斯分布规律参数化研究

Parameterized Study on Gas Distribution Law at the Secondary Lining Trolley

为了研究二次衬砌台车在不同因素影响下瓦斯的分布规律,利用Fluent流体力学软件建立压入式通风计算模型,讨论全断面施工时,风管出口风速、瓦斯释放源横向位置和纵向位置、台车阻滞系数对瓦斯分布规律的影响。研究结果表明,风管出口风速越大,对瓦斯的稀释作用越强;瓦斯释放源在风管异侧时,风流对瓦斯的稀释作用最强;瓦斯释放源位于拱顶处时,风流对瓦斯的稀释作用最弱;瓦斯释放源距离风管的纵向位置越近,瓦斯浓度越低;二次衬砌台车阻滞系数会影响隧道内瓦斯浓度的分布,台车阻滞系数越大,瓦斯浓度峰值越小。在实际施工中要尽可能地提高风管出口风速,注意瓦斯释放源的释放位置,合理地进行施工通风,同时为了避免瓦斯积聚,应注意二次衬砌台车前方处的瓦斯浓度。

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.