Underground spaces are characterized by special conditions and complexity, as well as by severe consequences in the event of an accident. Although the frequency of fire accidents in tunnels or metro stations is low, in worst cases they may lead to severe fatalities and damages. In order to have a more accurate prediction of fire impacts, most safety standards enforced worldwide suggest the development of special risk analyses. This needs to be made having in mind fire characteristics, geometrical and ventilation parameters so as to have an accurate view of the thermal and smoke propagation within the underground space. In this paper a parametric analysis is carried out, varying input values, crucial for fire risk analysis, like fire curve and heat release rate maximum (HRR_max), as well as ventilation and tunnel geometry. Key factors like visibility conditions, temperature and CO concentration are recorded through the fire dynamic simulation (FDS), in order to determine the conditions inside the metro tunnel. Furthermore, the fractional effective dose (FED) that occupants might receive in a period of time, in different positions inside the tunnel, is calculated. Based on the above, detailed data on the prevailing conditions are gathered and conclusions can be drawn regarding the influence of each parameter’s evolution on the tenability conditions inside the tunnel. Hence, the analysis can illuminate key issues to consider for performing an accurate risk analysis in an underground environment.

地下空间的特点是特殊条件和复杂性，以及在发生事故时的严重后果。尽管隧道或地铁站发生火灾事故的频率很低，但在最坏的情况下，它们可能会导致严重的死亡和损失。为了更准确地预测火灾影响，全球执行的大多数安全标准都建议进行特殊风险分析。这需要牢记火灾特性、几何和通风参数，以便准确了解地下空间内的热量和烟雾传播。在本文中进行了参数分析，改变输入值，对于火灾风险分析至关重要，如火灾曲线和热释放率最大值 (HRR _max)，以及通风和隧道几何形状。通过火灾动态模拟 (FDS) 记录能见度条件、温度和 CO 浓度等关键因素，以确定地铁隧道内的条件。此外，还计算了居住者在一段时间内、在隧道内的不同位置可能接受的分数有效剂量 (FED)。在此基础上，收集了有关主要条件的详细数据，并可以得出关于每个参数的演变对隧道内的韧性条件的影响的结论。因此，该分析可以阐明在地下环境中进行准确风险分析时要考虑的关键问题。