Shigen-to-sozai, Vol.116, No.7, pp.577-582.
Shear Displacement Behavior of Rocks in Shear
Fatigue Process
― Experimental study on cyclic fatigue process
of rocks under direct shear test (2nd Report)
―
Fumio SUGIMOTO1, Mitsumasa FURUZUMI2, Mamoru ABE3 and Tadao IMAI1
| 1. Faculty of Engineering and Resource Science,
Akita University, Akita 010-8502 2. Faculty of Engineering, Iwate University 3. Department of Geoscience and Technology, Graduate School of Engineering, Tohoku University |
| In this study, the behavior of upper and lower (permanent) shear displacements was investigated with cyclic shear loading tests for two kinds of rocks. The behavior of shear displacement obtained in this study may be classified into two processes. In one process, shear displacement is induced mainly by the closure of pores and cracks, the deformation within grains and sliding. In the other one, it is induced mainly by the growth of cracks. In case of neglecting the effect of normal stress, the slope of the equation expressing the relationship between the minimum rate of upper shear displacement and the number of cyclic loading on log-log graph is -1.02 for Kimachi sandstone and -0.92 for Tohoku marble. It is -1.09 for Kimachi sandstone and -1.00 for Tohoku marble when the rate of lower shear displacement is minimum. Upper shear displacement where the rate of upper shear displacement increases rapidly corresponds to shear displacement at the peak shear stress in the convenient direct shear test. Similarly, lower shear displacement where the rate of lower shear displacement increases rapidly corresponds to the permanent shear displacement at the peak shear stress. |
| KEY WORDS: Rock, Cyclic Shear Loading, Shear Displacement, Rate of Shear Displacement, Shear Stress-Shear Displacement Curve |