The reasons that the differences in temperature distributing and thermal stresses are produced in water conveying Box Bridge under solar radiation are analyzed in this paper. By FEM software ANSYS, temperature field and thermal stresses are simulated. Results indicate that temperature distribution in water-conveying concrete box bridge due to solar radiation is very complex. Temperature changes in the top plate are the most severe, followed by web-plate, with the bottom slab minimum. The actual temperature distribution can be approximately considered as conic curve. Under solar radiation considerable thermal stresses are produced in concrete box bridge both along the longitudinal and transverse direction and their value exceed tensile strength of the concrete. Therefore, thermal stresses under solar radiation must be considered in the design of water-conveying box bridge and temperature reinforcing bars should be appropriately added to the structure.

Heat transfer model of buried pipe heat exchanger is established first, and solved by the ANSYS finite element simulation software. Model is verified by experiment, average error is 6.4%. On the above basis, return water temperature of buried pipe and soil temperature are analyzed during whole operation. Through whole cooling season, outlet water temperature of buried pipe increased by 6.7°C, up to 21.2°C. After 45 days on transition season, temperature reduced 3.2°C, up to 18°C. Within one year, temperature difference is above 1.1°C before-and-after heating and cooling operation. It reveals that soil temperature cannot fully recover only by natural heat conduction and soil heat storage appears, which should be paid more attention in the project.