Iterative solution for evolution characteristics of air temperature and heat storage and release in surrounding rock and soil in subway interval tunnels over time
Wang Lihui[1] Lai Deqing[1] Zuo Hu[2] Chen Xinhao[1] Zhang Teng[1] Wang Hongdan[1]
Based on the CHAMPS-BES software, an iterative solution scheme coupling the interval tunnel heat balance model and the temperature field of surrounding rock and soil is proposed. Through multiple iterations, the evolution characteristics of the air temperature, the temperature field, and the heat storage and release in surrounding rock and soil in subway interval tunnels over time are obtained. The research results show that as the number of iterations increases, the accuracy of the tunnel air temperature gradually increases, which reflects the accuracy of this scheme. A study on a typical station interval tunnel in Shanghai finds that the temperature of surrounding rock and soil, wall temperature of surrounding rock, and tunnel air temperature show an increasing trend with the increase of operating years. The highest temperatures of surrounding rock and soil at different distances from the wall of the interval tunnel can reach 33.11, 34.16, and 36.03 ℃ during the early, middle, and long-term operational periods, and the lowest temperatures are 12.67, 15.33, and 17.00 ℃, respectively. Except for the long-term lowest temperature, which is located at a distance of 50 meters away from the wall, the rest are located at a distance of 0.1 meters away from the wall. The highest wall temperatures of surrounding rock can reach 33.27, 34.28, and 36.24 ℃ during the early, middle, and long-term operational periods, and the lowest temperatures are 12.63, 15.06, and 18.87 ℃, respectively. The highest air temperatures of interval tunnels can reach 35.36, 36.31, and 38.21 ℃ during the early, middle, and long-term operational periods, and the lowest temperatures are 11.86, 14.01, and 18.17 ℃, respectively. The surrounding rock and soil are mainly heat storage, and the total heat storage increases with the years, reaching a maximum of 425 922 MJ in September every year and a minimum in February every year.