Analysis of long-term temperatures inside tunnels during winter in Gangwon, South Korea

Tunnels are among the main components of transport infrastructure systems and as such must be protected against damage. As damage is particularly prevalent in cold climates, tunnels in Gangwon province, the coldest region of South Korea, were investigated in this research. The temperatures inside three tunnels (one short tunnel and two medium-length tunnels) were measured during the winter season (November to March) using iButton sensors installed on the surface of the tunnel linings at a height of 2 m from the ground. The long-term temperature data measured in this way were analysed and the results showed that January was the coldest month. The minimum and maximum daily air temperatures most frequently appeared during 3–6 a.m. and 2–4 p.m., respectively. The highest temperature gradient was found to occur 30 m from the entrance or exit. The temperatures inside the tunnels were significantly affected by external wind induced by vehicle traffic volumes compared with the natural wind direction, the wind velocity and rainfall. It is concluded that tunnel damage caused by frost heave and freeze–thaw action can be reduced by frequent inspection and evaluation.