兴隆坪隧道施工通风流场及天然气瓦斯分布规律研究

Study on construction ventilation flow field and gas distribution law of Xinglongping tunnel

以成都至贵阳高铁兴隆坪天然气高瓦斯隧道压入式通风设计为案例,运用离散化的数学方法模拟、分析流体流动和热交换理论,对隧道开挖进行了通风数值模拟,研究通风状态下瓦斯的分布及运动规律,并对比研究压入式通风不同时间段洞内不同位置的天然气瓦斯浓度、压力、逸散速度的变化情况,数值模拟分析表明:在压入式通风条件下,隧道内还存在部分区域瓦斯浓度值偏高的情况。为防止瓦斯积聚并为使整个隧道瓦斯浓度值保持在允许范围内,在施工过程中需增设通风竖井并配合局扇作为补充措施,以确保施工安全。

Taking the forced ventilation design of xinglongping natural gas and high gas tunnel of Chengdu to Guiyang high speed railway as an example,this paper uses the discrete mathematical method to simulate and analyze the fluid flow and heat exchange theory,carries out the ventilation numerical simulation of tunnel excavation,and studies the distribution and movement law of gas under ventilation,The changes of gas concentration,pressure and escape velocity of natural gas at different positions in the tunnel during different periods of pressure ventilation are compared and analyzed.The simulation analysis shows that under the condition of pressure ventilation,the gas concentration in some areas in the tunnel is still high.In order to prevent gas accumulation and keep the gas concentration value of the whole tunnel within the allowable range,ventilation shaft and local fan shall be added as supplementary measures during construction to ensure construction safety.