Intelligent adjustment ventilation duct design and numerical simulation study on enhancement of subgrade thermal stability in cold regions

Traditional ventilation duct systems for embankments in cold regions are limited in their ability to regulate ventilation, which restricts their cooling effectiveness on the subgrade. This study introduces a design method for an Intelligent Adjustment Ventilation Embankment (IAVE) system that dynamically adjusts the ventilation status within the duct based on variations in ground and air temperatures. Numerical simulations were performed to compare the cooling performance and differential settlement control of the Normal Ventilation Embankment (NVE), Temperature-Controlled Ventilation Embankment (TCVE), and IAVE systems. The results demonstrated that, compared to NVE and TCVE, the IAVE system achieved more precise temperature regulation, optimized the use of environmental cooling energy, and exhibited superior long-term cooling and differential settlement control. Among the three main factors influencing IAVE performance—ventilation duct burial spacing, burial depth, and airflow velocity—the burial spacing has the most significant impact on the Artificial Permafrost Table (APT). It not only enhances cooling during cold seasons but also effectively mitigates the re-warming of the subgrade during warm seasons. This research offers an efficient, low-carbon energy utilization structure and provides calculation results to improve the thermal stability of engineering projects in cold regions.