Microstructural Interpretation on Reliquefaction of Saturated Granular Soils under Cyclic Loading
by Masanobu Oda, (Prof., Dept. of Civ. and Envir. Engrg., Saitama Univ., Saitama, 338-8570, Japan), Ken Kawamoto, (Res. Assoc., Dept. of Civ. and Envir. Engrg., Saitama Univ., Saitama, 338-8570, Japan), Kiichi Suzuki, (Assoc. Prof., Dept. of Civ. and Envir. Engrg., Saitama Univ., Saitama, 338-8570, Japan), Hiroyuki Fujimori, (Grad. Student, Dept. of Civ. and Envir. Engrg., Saitama Univ., Saitama, 338-8570, Japan), and Masayuki Sato, (Chf. Engr., Tokyo Electric Power Service Co. Ltd., Tokyo 110-0015, Japan)
Journal of Geotechnical and Geoenvironmental Engineering, Vol. 127, No. 5, May 2001, pp. 416-423, (doi: http://dx.doi.org/10.1061/(ASCE)1090-0241(2001)127:5(416))
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Journal Paper |
| Abstract: |
It is well known that the resistance to liquefaction of a saturated sand decreases sharply when it has been presheared, either cyclically or quasistatically, beyond a threshold value. The possible mechanism is discussed in light of recent findings on the microstructural anisotropy developed in preshearing (induced anisotropy). A column-like structure, through which applied stress is mainly transmitted, grows parallel to the major principal stress direction in the strain hardening process. Voids, randomly distributed at first, are also connected in series between the column-like structures. The anisotropic structure can carry the increasing stress as long as the major stress is applied parallel to the elongation direction of the structure. However, it becomes extremely unstable when the major stress is rotated. The excess porewater pressure increases markedly under undrained cyclic loading, particularly when the connected voids are stressed perpendicular to their elongation direction. This is the reason why once liquefied sand sharply loses liquefaction resistance in a subsequent reliquefaction test. |
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