抄録
In many tunnels, icicles and side ices grow in cold climate. Against such a background we usually adapt an icicle prevention by adiabatic treatment for railway tunnel. We previously proposed optimum materials and optimum depth of heat insulator in consideration of statistical atomospheric conditions for the prevention. This paper deals with a thermal behavior of a near end of the heat insulator affected by the cold in non-treated area, and a marginal length which has to be set aside in length of the heat insulator. A two dimensional nonsteady state heat conduction tunnel model is proposed. After the analyzed values are found to well agree with the measured ones of an exisiting tunnel, we propose the marginal length for insulator width according to atomospheric conditions.
