Heat balance model for long-term prediction of the thermal regime of a subway tunnel and surrounding soil

TL;DR

This paper develops a heat balance model using finite element analysis to predict long-term temperature variations in subway tunnels and surrounding soil, considering seasonal atmospheric changes and tunnel ventilation effects.

Contribution

It introduces a comprehensive heat balance model for long-term thermal prediction of subway environments, including soil and tunnel interactions, with numerical analysis of parameter influences.

Findings

Estimated the size of heated soil regions between tunnels.

Analyzed the impact of model parameters on tunnel and soil temperatures.

Provided a numerical solution approach for long-term thermal behavior.

Abstract

For a long-term forecast of the average air temperature in a metro tunnel and surrounding soil, heat balance conditions are modeled in a system that includes two parallel tunnels, a near-tunnels underground space, the earth's surface and atmospheric air with seasonal temperature variation. It is assumed that the air in the tunnels is well mixed, and the thermal effect of ventilation is taken into account by replacing the air in the tunnels with atmospheric air. The system of heat balance equations is solved numerically by the finite element method. A numerical analysis of the influences of the model parameters on the average temperature in the tunnels and surrounding soil is carried out. The dimensions of the soil region with an elevated temperature, located between the tunnels, are estimated.