1. 1) Agostini, R., Cesario, L., Conti, A., Masetti, M. and Papetti, A.: Flexible gabion structures in earth retaining works, Officine Maccaferri S. p. A., 1987.
2. 2) Christoffersen, J., Mehrabadi, M. M. and Nemat-Nasser, S.: A micromechanical description of granular material behavior, J. Appl. Mech., 48, pp. 339-344, 1981.
3. 3) Thornton, C. and Barnes, D. J.: Evolution of stress and structure in particulate material, Chap. 11, in: Applied Solid Mechanics -1, (eds) A. S. Tooth and J. Spence, Elsevier, 1986.
4. 4) Endres, A. L.: The effect of contact generation on the elastic properties of a granular medium, J. Appl. Mech., 57, pp. 330-336, 1990.
5. 5) 金谷健一: 粒状体の粒子モデルと仮想仕事の原理, 土質工学会論文報告集, 20, No. 3, pp. 111-116, 1980.