针对交通瓦斯隧道现有标准存在的设防标准偏高、建设成本较高和不适用于高海拔地区等问题，结合数值模拟和理论分析进行研究。通过建立数值模型分析平均风速和瓦斯体积分数在空间上的动态变化，提出风速安全系数和瓦斯体积分数安全系数，并确定了稳定回风流断面的位置。对高海拔环境条件进行模拟，揭示不同海拔对瓦斯爆炸特性、爆炸极限和瓦斯体积分数的影响机制，通过引入基于海拔的瓦斯爆炸极限影响系数和瓦斯体积分数影响系数，建立平原瓦斯隧道与高海拔瓦斯隧道之间的关联模型。研究主要成果为： 1）针对现行交通隧道瓦斯工区分级标准，改进分级标准值的计算公式，提出考虑不同隧道回风流断面面积大小的分级标准； 2）优化瓦斯涌出不均衡系数取值，并将其与风速安全系数和瓦斯体积分数安全系数引入现行施工阶段绝对瓦斯涌出量实测值计算公式，提出修正后的实测值计算公式； 3）针对高海拔瓦斯隧道，提出适用于不同海拔的瓦斯工区分级标准值计算公式和分级标准。
Existing standards for gas hazards in traffic tunnels
have several limitations, including overly stringent safety measures and high
construction costs that are not feasible in high-altitude
regions. To address these issues, numerical simulation and theoretical analysis
methods are employed in this study. A numerical model is developed to analyze
the dynamic spatial variations of average wind speed and gas concentration,
leading to the proposal of safety factors for both wind speed and gas
concentration and the determination of the stable return airflow section. The
study simulates high-altitude environmental conditions
to reveal the mechanisms by which altitude influences gas explosion
characteristics, explosion limits, and gas concentration. Altitude-based coefficients for gas explosion limits and concentration are
introduced to establish a correlation model to link gas tunnels in flat regions
with those in high-altitude regions. The main findings
of the study are as follows: (1) A revised calculation formula for the
classification standards of gas work areas in traffic tunnels is proposed,
incorporating adjustments for the cross-sectional area
of return airflow sections. (2) The disequilibrium coefficient for gas emission
is optimized and integrated into the calculation formula for measured absolute
gas emissions during the construction phase, along with safety factors for wind
speed and gas concentration, to yield a modified formula. (3) For high-altitude gas tunnels, a classification standard suitable for varying
altitudes is proposed, including a formula for calculating classification
values and standards.
