Quantifying ground temperature characteristics affected by underground buildings in spatial-temporal distributions

Abstract

Ecological and human environments face growing threats from the severe Subsurface Urban Heat Island (SUHI) effect, which simultaneously presents opportunities for shallow geothermal energy utilization. Underground buildings emerge as a key driver of ground temperature change—both the dynamic effects of underground buildings on ground temperature and their hourly spatial-temporal distribution remain poorly characterized. This knowledge gap not only restricts the efficient utilization of ground source heat pumps, but also causes unnecessary environmental pollution. In this context, this study simulates the dynamic effect of the water table, hydraulic head, and the geometric dimensions and temperature operation modes of underground buildings on the surrounding ground temperature field under the hydrogeological conditions of Beijing, China. Key findings include: (1) the influence of hydraulic gradient on ground temperature increases with horizontal distance, while soil thermal conductivity shows an asymmetric response to ±20% variation; (2) water table depth governs lateral thermal asymmetry, with higher water tables enhancing upstream–downstream temperature differences; (3) building width impacts vertical temperatures 2.4 times more than depth, while horizontal effects depend solely on depth; (4) building types induce distinct seasonal fluctuations, with amplitudes increasing over time and peaking in early spring; and (5) the interaction of geometric dimensions and temperature operation modes produces more pronounced and divergent ground temperature variations (+ 3.3 °C at 40 m depth, seasonal swing 11–22.5 °C) penetrating to 80 m depth. These insights contribute to mitigating SUHI and improving the utilization of geothermal resources.