高地温尼格隧道综合降温体系研究

为解决高地温隧道因高温引发的热害问题，以红河州建水—元阳高速公路的尼格隧道为依托，基于能量平衡原则设计各降温措施的适用区间。采用CFD软件模拟进行对照分析，研究尼格隧道现场采用降温措施的效果，构建高地温隧道综合降温体系。结果表明： 1）围岩温度T<32 ℃时采用单通风管道，在围岩温度32 ℃≤T≤40 ℃时采用双通风管道，在围岩温度40 ℃<T≤48 ℃时增设局部雾炮车喷雾降温，在围岩温度T>48 ℃增设冰块降温，且在实际应用中温降可达到理论计算值。2）增大通风量对降温速率的影响最大，可提升37.7%；冰块降温次之，可提升11.6%；喷雾降温提升效果最差，仅提升3.2%；但是对于降温幅度，冰块降温>增大通风量>喷雾降温。3）增大通风量可以加快洞内空气的置换流通，宜作为基础降温措施；冰块降温通过融化吸热可实现大规模的温降，可用在热害等级较高的隧道；喷雾降温可实现局部区域的降温、除尘和加湿，可作为掌子面辅助降温措施实现对隧道的局部降温。

Comprehensive Cooling System of Nige Tunnel with High Ground Temperature

The heat damage caused by high temperature is a severe problem in tunnels with high ground temperature. As a result, the applicable interval for each cooling measure is designed for the Nige tunnel of the Jianshui-Yuangyang expressway in Honghe Prefecture, China, based on the principle of energy balance. Then, the computational fluid dynamics software simulation is used to analyze the cooling effect of the measures adopted, and a comprehensive cooling system for high ground temperature tunnel is constructed. The findings are as follows: (1) A single ventilation pipe can be used when the surrounding rock temperature is less than 32 ℃. A double ventilation pipe can be used when the surrounding rock temperature is between 32 ℃ and 40 ℃. An additional local fog truck spray cooling can be installed when the surrounding rock temperature is between 40 ℃ and 48 ℃, and additional ice cooling can be installed when the surrounding rock temperature is greater than 48 ℃. The temperature drop can reach the theoretical calculation value in practical application. (2) An increase in the ventilation air volume has the greatest impact on the cooling rate, which can be increased by 37.7%; the ice cooling can increase the cooling rate by 11.6%, and spray cooling can increase the cooling rate by 3.2%. While ice cooling has the greatest cooling range, followed by increasing ventilation air volume, and spray cooling has the smallest. (3) Increasing the ventilation air volume can accelerate the air replacement circulation in the cave, which can be regarded as a basic cooling measure. Ice-cooling can achieve large-scale temperature reduction by melting and absorbing heat, which can be used in tunnels with high heat damage level. Spray cooling can achieve local area cooling, dust removal, and humidification, which can be used as an auxiliary cooling measure for tunnel face to achieve local tunnel cooling.