地下综合管廊在城市规划发展过程中发挥着重要的作用，目前我国已有超过150个城市将管廊建设提上日程。但作为受限空间，管舱内部各种管线共存并相互干扰，也往往会带来不可忽视的新风险。实际上, 地下环境内电缆及热力管道作为廊内的局部热源，容易导致热聚集现象以及温度的不均匀分布，这将造成气体扩散的“热耦合效应”。可见管廊内环境的耦合风险效应将成为当前管廊安全以及保证社会安全的重要课题之一。本研究建立了多种内环境耦合影响因素下的管廊模型管廊模型，利用数值模拟、数学模型构建、数据验证等方法，研究了管廊内环境在热耦合情况下的灾害机理，并进一步提出相应的管廊设备优化措施，研究成果对未来的管廊灾害分析具备经验及指导意义，主要内容包括以下几个方面：1.通过改良的OpenFoam解算器建立了理想状态下管廊热耦合扩散模型。发现温差会导致明显的气体扩散热耦合效应，且温差越大，气体热扩散效应越明显。为保证管廊内一旦发生气体泄漏，监测器不会由于管廊内扩散的热耦合效应而出现预测延迟风险，管廊内温差最好不要超过10K。2.建立了基于Fick定律的一维条件下热耦合扩散浓度模型，并利用模拟数据对比后Pearson系数达0.78，验证了本模型结果的合理性。热耦合扩散负增量满足Δx=t·((22.4·pD_A)/(RT^2 )·(a·(ΔT+b)^c+d))，上式可以有效对观测线上气体扩散距离进行预测矫正，从而提出应对方案。3.利用OpenFoam和Fluent建立管廊泄漏实例模型，发现在考虑热耦合情况下，监测点处气体扩散平均值为0.286m/s，而不考虑热耦合情况时为0.413 m/s，同时泄漏管道孔口位置及内部管道布局会对气体的流动产生微弱影响。4.热源温差，通风、喷淋强度会对管廊内气体扩散起决定性作用，通风可有效加快气体扩散，平均通风量为4m/s左右可有效平衡管廊实例中热耦合附加效应值；喷淋可有效降低防火分区内温度，放缓扩散影响；而两者耦合可以强化作用效果，降低热效应作用。同时，作为指导管廊内设计安全及经济效应间平衡的决策建议，本研究还基于传感器灵敏度LEL值及报警时间限度，提出了关于不同容忍度下廊内气体预警系统安装间距建议。

Underground utility tunnel plays an important role in the process of urban planning and social development. At present, more than 150 cities in our country have put the construction of utility tunnels on the agenda. However, as a confined space, various pipelines in the utility tunnel coexist and interfere with each other, which will also bring risks that cannot be ignored. In the past, researchers paid lots of attentions to the process of gas diffusion and leakage, ignoring the influence of surrounding environmental conditions. In fact, as a local heat source in the tunnel, cables and thermal pipelines easily lead to heat accumulation and uneven distribution of temperature, which will cause "thermal coupling effect" of gas diffusion. Therefore, it is necessary to study the coupling risk effect of the environment in the utility tunnel, especially the law of gas leakage and diffusion. The thermal coupling effect of gas will become one of the important topics for the safety of utility tunnel and social safety.This study established a utility tunnel model including a variety of internal environment coupling factors through OpenFoam. Using the methods of numerical simulation, mathematical model construction and data verification, the differences of gas diffusion laws caused by thermal changes are studied, the disaster mechanism of the internal environment of the utility tunnel under the condition of thermal coupling is analyzed, and the corresponding utility tunnel equipment optimization measures are further proposed. The research results have experience and guiding significance for future utility tunnel disaster analysis. The main contents include the following aspects: Through the modified OpenFoam solver, the thermal coupling diffusion model of the utility tunnel under ideal state is established. It is found that the temperature difference will lead to obvious thermal coupling effect of gas diffusion, and the larger the temperature difference, the more obvious the thermal diffusion effect of gas. Different heat source positions will cause different gas concentration changes. In order to ensure that once gas leakage occurs in the utility tunnel, the monitor will not have the risk of prediction delay due to the thermal coupling effect diffused in the utility tunnel, and the temperature difference in the utility tunnel should not exceed 10K. A one-dimensional thermally coupled diffusion concentration model based on Fick's law is established. Pearson coefficient is 0.78 after comparing the simulation data, which verifies the rationality of the model results. This model can effectively predict and correct the gas diffusion distance. OpenFoam and Fluent software are used to establish case models of leakage respectively. It is found that the orifice position of the leakage pipeline and the internal pipeline layout will have a slight influence on the gas flow.Among the coupling factors of internal environment, thermal temperature difference, ventilation intensity and spray intensity play a decisive role in the gas diffusion distance, and ventilation can effectively accelerate the gas diffusion speed. Spraying can effectively reduce the temperature in the fire prevention zone and slow down the overall diffusion of gas. The coupling of the two can strengthen the effect and reduce the thermal effect in confined space. Based on the LEL value of sensor sensitivity and the limit of alarm time, this study puts forward suggestions for the installation spacing of sensors under different tolerance.