This paper describes field experiments and evaluation on a snow melting system by using underground thermal energy in order to verify its energy saving performance. Firstly, experiments on a snow melting tank with a vertical earth heat exchanger which is 30m in depth were made and it was found that the heat extraction rate from the underground reached approximately 1.4kW. Secondly, an evaluation program on the snow melting system was developed, and the program was verified to give good predictions on the system performance.
As a result of system simulations on a snow melting area, a length of the vertical earth heat exchanger and the tank volume, it was clarified that the energy consumption and CO² emissions were greatly reduced comparing with conventional snow melting systems.

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The authors discussed the existing method to evaluate the avalanche risk for Hokuriku Shinkansen, and specified its meanings from the engineering viewpoint. In the method, the avalanche risk was determined qualitatively as the product of starting risk and the risk to reach the site under consideration. However, the meaning of the calculated avalanche risk was not defined in qualitative terms. In order to take measures against the avalanche for Tohoku Shinkansen from Morioka to Hachinohe at the entrance of each mountain tunnel, the risk was first evaluated by using the same method as that for Hokuriku Shinkansen. Second, the resistance to the expected avalanche load was discussed with special attention paid to the existing structures, such as buffering works to minimize the effect of micro-pressure waves. Consequently, the avalanche resistance of the existing structures was found to be approximately 20kN/m². Furthermore, avalanches with a load of not less than 20kN/m² may occur at slopes whose avalanche risk was greater than 70%.

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