双洞隧道独头掘进CO扩散效应模拟分析

Simulation analysis of CO diffusion for double tube tunneling excavated from single end

基于CFD的基本理论,对某双洞公路隧道和其压入式通风系统建立三维模型,利用RNG k-ε湍流模型模拟双洞隧道独头掘进时CO扩散规律,得出非稳态下CO扩散数据模型。用2个指标(CO扩散浓度、污染持续时间)来量化污染严重程度。研究发现双洞隧道独头掘进时,如果2条隧道的通风功率不一样,一条隧道掌子面爆破作业后产生的CO会沿着双洞隧道间的人行横道扩散,进而影响另一条隧道的空气质量。根据爆破后的双洞等功率通风CO扩散效果的研究,提出了更为合理的通风管理措施。

Based on theory of CFD, a numerical 3D simulation model of road double tube tunneling and its venti lation system were established which were used to analyze CO diffusion law by applying the RNG k - 8 turbulent - flow model and obtain CO diffusion data model under unsteady stete. To quantize the degree of contamination, two indexes （ i. e. , CO diffusion concentration and the lasting time of contamination） were adopted. The results show that, when the double tunnels were excavated from single end, supposing the ventilating power of two tun-nels being different, CO will diffuse into neighboring tunnel through pedestrian crossing between two tunnels after the blasting of heading face of the one tunnel, and thus the air in the neighboring tunnel is seriously contamina ted. The more practical and suitable ventilation managements are proposed, according to the research of the im-pact of CO diffusion that is derived with equal ventilating power of two tunnels after blasting.