With the development of society and the growth of population, the demand for energy continues to increase. Utilizing subway source heat pump technology to extract shallow geothermal energy for cooling or heating for users, making shield tunnel subways become energy tunnels, is one of the most effective technologies to solve the problem of energy demand. However, the thermal impact of heat exchanger operation on tunnel structures still needs further research. Based on COMSOL Multiphysics software, this paper analyzes the heat exchange performance of the Capillary Heat exchanger (CHE) in energy tunnels and the structural mechanical response of shield tunnel segments during CHE operation under typical heating season and cooling season conditions. The results indicate that the performance of precast CHE in energy tunnels is excellent. A single-ring energy tunnel can provide cooling and heating capacities of 601.62W and 466.28W, respectively, during the cooling and heating seasons, with heat transfer efficiency of 63.46W/m² and 49.19W/m² respectively. The operation of the CHE during the cooling season leads to elongation of the tunnel segments, while during the heating season, compression of the tunnel segments occurs. The maximum tensile stress and maximum compressive stress generated in heating season are 0.60 MPa and 0.73 MPa respectively, while in cooling season they are 0.56 MPa and 0.87 MPa respectively. The compressive stresses generated during the cooling and heating seasons due to CHE operation are far below the compressive limit of C50 concrete, with tensile stresses representing 33% and 23% of the axial tensile strength, respectively. The calculation results indicate that under the design conditions of the heat pump unit, when the heat exchange between the CHE and the tunnel reaches steady state, the impact of CHE heat exchange on the structural integrity of the shield tunnel is relatively minor.