Numerical investigation on the maximum and longitudinal distribution of ceiling gas temperature in an inclined tunnel: The combination effect of tunnel slope and longitudinal fire location

IF 6.7 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Tunnelling and Underground Space Technology Pub Date : 2025-05-05 DOI:10.1016/j.tust.2025.106685

Longxing Yu , Xiwen Lei , Lingxiang Wang , Ping Huang , Chunxiang Liu

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Abstract

Numerical investigation was carried out to study the ceiling gas temperature distribution under the combination effect of tunnel slope and longitudinal fire location in a naturally ventilated tunnel. Results show that in horizontal tunnel with fire located in the tunnel’s longitudinal center, the ceiling gas temperature is symmetric distributing in upstream and downstream. With fire moves to the right (downstream) portal, the ceiling gas temperature in upstream tunnel decays faster than that in downstream, and vice versa. For inclined tunnels (going uphill), the ceiling gas temperature is asymmetrically distributed even the fire is located in the longitudinal center. Interestingly, with fire moves to downstream, it would become symmetric again and then it returns to asymmetric. Therefore, the tunnel slope and the longitudinal fire location have complex combination effect on the ceiling gas temperature distribution. More interestingly, with the fire moving from upstream to downstream in an uphill tunnel, the evolution of maximum ceiling gas temperature shows two tendencies, depending on the tunnel slopes. For smaller tunnel slopes, the maximum ceiling gas temperature first increases and then decreases, while it increases monotonically for larger tunnel slopes. Consequently, the critical tunnel slope for the change of two tendencies was proposed, which shows the variation of the relative strength of the two effects. For tunnel slopes lower than the critical value, the two effects are comparable. For tunnel slopes larger than the critical value, the tunnel slope is the dominant effect. In addition, the empirical equation of offset distance was proposed as intermediate variable to characterize the combination effects on the maximum ceiling gas temperature. By taking the absolute value of offset distance as characteristic parameter, the predicting equation for the maximum ceiling gas temperature was proposed.

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倾斜隧道顶板温度最大值和纵向分布的数值研究：隧道坡度和纵火点的联合效应

对某自然通风隧道在巷道坡度和纵火点共同作用下的顶板温度分布进行了数值研究。结果表明：在火灾位于隧道纵向中心的水平巷道中，顶板温度在上下游呈对称分布；随着火势向右（下游）入口移动，上游隧道顶板温度衰减速度快于下游隧道，反之亦然。对于倾斜巷道（上坡），纵火点位于巷道纵向中心，顶板温度分布也不对称。有趣的是，随着火向下游移动，它会再次变得对称，然后又回到不对称。因此，隧道坡度和纵火区位置对顶棚气体温度分布具有复杂的组合效应。更有趣的是，随着火灾在上坡隧道中由上游向下游移动，最大顶板温度随隧道坡度的变化呈现出两种趋势。对于较小坡度的隧道，最大顶气温度先升高后降低，而对于较大坡度的隧道，最大顶气温度单调升高。据此，提出了两种趋势变化的临界边坡，反映了两种趋势相对强度的变化规律。对于低于临界值的隧道边坡，两者的影响具有可比性。当隧道边坡大于临界值时，隧道边坡是主导效应。此外，提出了偏置距离作为中间变量的经验方程来表征组合效应对最高顶气温度的影响。以偏置距离绝对值为特征参数，提出了最高顶棚气体温度的预测方程。

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来源期刊

Tunnelling and Underground Space Technology 工程技术-工程：土木

CiteScore

11.90

自引率

18.80%

发文量

454

审稿时长

10.8 months

期刊介绍： Tunnelling and Underground Space Technology is an international journal which publishes authoritative articles encompassing the development of innovative uses of underground space and the results of high quality research into improved, more cost-effective techniques for the planning, geo-investigation, design, construction, operation and maintenance of underground and earth-sheltered structures. The journal provides an effective vehicle for the improved worldwide exchange of information on developments in underground technology - and the experience gained from its use - and is strongly committed to publishing papers on the interdisciplinary aspects of creating, planning, and regulating underground space.