Tunnels are nowadays key elements in transport networks worldwide. To achieve a safe and efficient operation, a proper integration and design of Mechanical, Electrical and Intelligent Transportation Systems is required. Among these systems, tunnel ventilation is one of the most critical ones from the Fire Life Safety perspective, being smoke control to maintain safe conditions during self-evacuation and rescue operations one of its main objectives. Traditionally tunnel ventilation systems are sized following a deterministic approach. Designers, based on requirements and design criteria from Standards and Recommendations, focus on a limited number of fire scenarios and design parameters to reach a solution considered acceptable from a fire safety perspective. This paper proposes the use of a probabilistic approach to assess, in terms of probability of failure, the capacity of a tunnel ventilation system for fire scenarios. The model applied in the proposed process uses a 1D steady state model based on pressure losses, where critical design variables are considered random (unlike with the deterministic approach) to calculate a failure probability associated to an installed ventilation thrust. A case study example is used to analyse results using both, the traditional deterministic approach and the proposed probabilistic one. Results obtained with the deterministic approach show how, under the same design requirements, tunnels with similar characteristics allow different safety margins for the capacity of the ventilation system. These results are confirmed numerically using the probabilistic approach by evaluating failure probabilities. To avoid this, the paper proposes the use of the probabilistic approach to allow a definition of an equivalent uniform safety margin (to achieve a certain probability of failure) which would be of significant help for designers, administrations and tunnel operators. It is not the aim of the study to define the limit for the probability of failure or to characterise the design variables, but to present a useful tool with which important conclusions about the design criteria can be obtained.

中文翻译：

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使用概率方法进行隧道通风分析：案例研究，纵向通风道路隧道中的火灾

如今，隧道是全球交通网络中的关键要素。为了实现安全高效的运行，需要对机械、电气和智能交通系统进行适当的集成和设计。在这些系统中，从消防生命安全的角度来看，隧道通风是最关键的系统之一，它是在自我疏散和救援行动期间控制烟雾以保持安全条件的主要目标之一。传统上，隧道通风系统是按照确定性方法确定大小的。设计师根据标准和建议中的要求和设计标准，专注于有限数量的火灾场景和设计参数，以达成从消防安全角度被认为可接受的解决方案。本文建议使用概率方法来评估，就故障概率而言，隧道通风系统在火灾情况下的容量。在建议的过程中应用的模型使用基于压力损失的一维稳态模型，其中关键设计变量被认为是随机的（与确定性方法不同）来计算与安装的通风推力相关的故障概率。案例研究示例用于分析使用传统确定性方法和建议的概率方法的结果。使用确定性方法获得的结果表明，在相同的设计要求下，具有相似特性的隧道如何为通风系统的容量提供不同的安全裕度。这些结果使用概率方法通过评估失效概率在数值上得到证实。为了避免这种情况，该文件建议使用概率方法来定义等效的统一安全裕度（以实现一定的故障概率），这将对设计者、管理人员和隧道运营商有很大帮助。研究的目的不是定义失效概率的极限或描述设计变量的特征，而是提供一个有用的工具，通过它可以获得关于设计标准的重要结论。