1. 1) K. Aoki, T. Inaba, Y. Shiogama and Y. Tezuka, “Evaluation of geological conditions by drilling logging system”, Proceedings of the 8th Japan Symposium on Rock Mechanics, pp.67-72 (1990).
2. 2) H. Schunnesson, “Rock characterisation using percussive drilling”, International Journal of Rock Mechanics and Mining Sciences, Vol.35, No.6, pp.711-725 (1998).
3. 3) S. Minagawa, M. Arakawa, T. Itoh and S. Hashizume, “Prediction of geological condition of forward tunnel face with drilling energy and the behavior of tunnel excavated”, Proceedings of tunnel engineering, JSCE, Vol.8, pp.139-144 (1998).
4. 4) T. Hara, S. Kumagai, T. Kimura and T. Hirano, “Sequential application of several survey systems in tunneling for accurate ground classifications”, Proceedings of tunnel engineering, JSCE, Vol.12, pp.189-194 (2002).
5. 5) R. Hikima, K. Isjiyama, J. Tsukada and Y. Ishii, “The comparison of geological survey system using hydraulic drilling to face and core boring in soft sedimentary rock”, Proceedings of the 30th Symposium on Rock Mechanics, pp.238-242 (2000).