Numerical simulation and experimental validation of the thermal environment in river-crossing cable tunnels: Influence of soil thermal conductivity

Cheng, Jin, Zhong, Ke, Wang, Yiqi, Wang, Liang and Kang, Yanming 2026. Numerical simulation and experimental validation of the thermal environment in river-crossing cable tunnels: Influence of soil thermal conductivity. International Communications in Heat and Mass Transfer 178 (2) , 111614. 10.1016/j.icheatmasstransfer.2026.111614

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Abstract

Due to the difficulty of constructing artificial islands in rivers or seas, overheating risk is particularly pronounced in river-crossing cable tunnels (RCTs) crossing such water bodies, where ventilation length is significantly large. The accuracy of ventilation volume predictions depends on the soil heat absorption quantity, which is primarily controlled by soil thermal conductivity (λs). In practice, λs is typically assumed to be a constant based on national standards (e.g. 1.16 W/(m·oC) in China). However, this simplification neglects the inherent variability of soil thermophysical properties and can introduce substantial design errors. This study investigates the sensitivity of tunnel thermal behavior and soil heat flux to variations in λs using a numerical model validated through experiments conducted on a scaled tunnel test platform. Results show that increasing λs from 0.17 to 1.36 W/(m·oC) leads to a 64% difference in the average lag time of peak soil temperatures at 2.0 m depth, and the temperature gradient at the tunnel wall and the overall heat transfer intensity differ by 50% and 220%, respectively. Consequently, using the recommended λs (1.16 W/(m·oC)) can underestimate the overheated space length ratio (ξ) by up to 98% and misjudge the duration of high-temperature period, which in turn causes deviations in tunnel overheating predictions. The present study provides a theoretical basis for designing ventilation systems in long tunnels crossing rivers and seas.

Item Type:	Article
Date Type:	Published Online
Status:	Published
Schools:	Schools > Architecture
Publisher:	Elsevier
ISSN:	0735-1933
Last Modified:	18 Jun 2026 08:45
URI:	https://orca.cardiff.ac.uk/id/eprint/187612

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