School of Emergency Management and Safety Engineering, China University of Mining and Technology-Beijing, Beijing, 100083, China.
Beijing Key Laboratory of Metro Fire and Passenger Transportation Safety, China Academy of Safety Science and Technology, Beijing, 100012, China.
Environ Sci Pollut Res Int. 2022 Sep;29(44):67063-67075. doi: 10.1007/s11356-022-20370-3. Epub 2022 May 5.
Thermal hazards of the surrounding rock of subway tunnels are becoming apparent, in which the heat transfer in the surrounding rock plays a crucial role. Due to the shallow buried depth, the subway tunnel encounters a more complicated heat exchange under the duplicate effects of periodic temperature fluctuation of ground atmosphere and periodic temperature variation of tunnel wind, but this issue has not been fully addressed. In this work, a transient heat transfer model of tunnel surrounding rock based on dual periodic temperature boundaries was established. A solver was developed to estimate the temperature rise and heat transfer of surrounding rock. The correctness of this model was then verified by comparing with previous empirical values and semi-empirical equations. The results show that the temperatures of the surrounding rock at different depths still fluctuate following the simple harmonic waves, and there are some regions that are heavily affected by the duplicate effects, such as the overlying strata of the tunnel. The surrounding rock generally exhibits heat storage in annual cycle, but the total heat storage decreases year by year until it tends to stabilize. Furthermore, the shallower the tunnel is buried, the greater the influence of ground temperature and the higher the temperature rise in the tunnel surrounding rock. This research provides an alternative approach to determine the heat storage of tunnel surrounding rock and evaluates the process of thermal disaster manifestation of subway.
地铁隧道围岩的热危害日益明显，其中围岩的传热起着至关重要的作用。由于埋深较浅，地铁隧道在周期性地受到地面大气温度波动和隧道风流周期性温度变化的双重影响下，会遇到更为复杂的热交换，但这一问题尚未得到充分解决。在这项工作中，建立了一个基于双周期温度边界的隧道围岩瞬态传热模型。开发了一个求解器来估算围岩的温升和热传递。然后通过与先前的经验值和半经验公式进行比较来验证该模型的正确性。结果表明，不同深度的围岩温度仍按照简谐波规律波动，并且存在一些受重复影响较大的区域，如隧道的覆盖层。围岩在年周期内普遍表现出蓄热，但总蓄热量逐年减少，直到趋于稳定。此外，隧道埋深越浅，地面温度的影响越大，隧道围岩的温升越高。这项研究提供了一种确定隧道围岩蓄热的替代方法，并评估了地铁热灾害表现的过程。
