关键词: 隧道仰拱, 软塑黄土, 换热性能, 温度应力, 现场试验

Abstract: Energy tunnel, which is based on ground source heat pump system, is one of the green, economical and efficient geothermal heat exchange techniques. It can integrate both the anti-freezing and heat preservation for tunnel. Based on the Yinchuan-to-Xi′an high-speed railway tunnel located in loess region, the heat exchange tubes are placed in series in the tunnel invert, and the ground source heat pump system has been built. The heating system is operated under different input powers as well as the inlet and outlet temperature, and the temperature and stresses of the inverted arch are measured. The thermal response characteristics of the tunnel under difference input powers are discussed and analyzed, including heat transfer capacity and thermal induced stresses, etc. Under this field test condition, the results show that the temperature of the inverted arch of tunnel has increased by 4.2℃ and 7.1℃ under 0.5 kW and 1.0 kW input power, respectively. With the increase of water temperature, the invert temperature increases slightly in a short period of time. When the heat propagation path has stabilized, the invert temperature finally presents a linear relationship. The increment of axial stress of the inverted arch of tunnel is larger than that of the longitudinal stress. The axial stresses are 1.15 and 1.29 times of longitudinal stresses under 0.5 kW and 1.0 kW input power, respectively.

Key words: tunnel invert, soft plastic loess, heat transfer capacity, temperature stress, field test