Dimensionless analysis of soil temperature field of shallow subway tunnel

Abstract

For evaluating the long-term heat storage capacity of a shallow subway tunnel's soil layer, a dimensionless mathematical model is established based on the heat conduction of tunnel surrounding rock. Using the finite volume method, the heat balance equations of the dimensionless internal and boundary elements for the soil temperature field are solved numerically. An analysis of the evolution of soil temperature field and tunnel wall temperature with time is presented in this paper. A long-term heat exchange results in a significant coupling superposition effect between the atmospheric air temperature disturbance domain and the subway air temperature influence domain in the subway tunnel. In addition, a simple calculation method for the unstable heat transfer criterion is provided by looking at a chart, and the long-term heat storage capacity of tunnel surrounding rock can be determined quickly. An engineer can use this method to expeditiously design the environmental control system of a subway tunnel.