Non-coaxial constitutive response of idealized 3D granular assemblies to rotation of principal stress axes

* Dr. of Agr., Research Associate, Dept. of Marine System Eng., Kyushu University, Fukuoka 812-8581 ** Dr. of Eng., Assistant Professor, Dept. of Environmental and Civil Eng., Hachinohe Inst. Tech., *** Dr. of Eng., Professor, Dept. of Marine System Eng., Kyushu University, Fukuoka 812-8581 **** Dr. of Eng. and Dr. of Agr., Professor, Dept. of Agr. Eng., Kyushu University, Fukuoka 812-8581 ***** Dr. of Eng., Professor, Dept. of Civil. Eng., Tohoku University, Sendai 980-8579