In this paper,eight tunnels of a railway line were chosen to observe and analyze the temperature of tunnel wall,air temperature inside the tunnel and relative humidity.Based on the FEM program ABAQUS,the fluid-solid numerical models of the tunnel were established to analyze the influence of wind speed of tunnel portal,tunnel length and air temperature of tunnel portal on the temperature field of long tunnels.According to above analysis,the mechanism of condensation on tunnel walls under hydrothermal environment was analyzed.The results showed that the temperature and moisture distributions of long tunnels can be divided into three regions: quick-change region,smooth transitional region and constant region.In the constant region,the temperature and humidity were little affected by external environment.The condensation on tunnel walls in hot and humid areas was mainly caused by internal and external temperature differences and high humidity.The wind speed of tunnel portal was linearly related to the size of the constant region.The faster the wind speed,the smaller the constant region was.Under the same outside air temperature,the longer the tunnels,the faster the air temperature inside the tunnel reduced.The outside air temperature only affected certain regions near the tunnel portal.%以某铁路隧道为依托,选取其中8座典型隧道,对隧道洞壁温度、洞内气温以及相对湿度进行连续观测并整理分析.基于ABAQUS有限元软件建立隧道的流固耦合数值模型,得到了洞口风速、隧道长度和进风口风温等因素对长大隧道温度场的影响规律.在此基础上,对湿热环境下长大隧道洞壁结露现象产生机制进行了分析.研究结果表明:长大隧道温湿度场可分为快速变化区、平缓过渡区和恒定区,在恒定区内隧道温度、湿度变化受外界环境影响较小.湿热气候下的洞壁结露现象主要是由于较高的内外温差和大气湿度引起的.洞口风速与隧道恒定区大小呈线性关系,且风速越大,恒定区范围越小.在洞外气温相同的情况下,隧道越长,洞内气温衰减越快,而洞外气温仅对隧道口一定区域产生影响.
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