Why the OCR may reduce the small strain shear stiffness of granular materials?
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The small strain shear stiffness G0 of the soil is of interest and importance in both theory and practice. It is expected that for granular materials G0 would slightly increases with over-consolidation ratio (OCR). However, laboratory tests indicate that G0 may decrease with increasing OCR, especially for loose specimens, which is counterintuitive. To explore the underlying mechanism, discrete element method (DEM) is used to investigate the effect of OCR on G0. The DEM simulations successfully capture the laboratory observations. The analyses at the particulate level reveal that the decrease in small strain stiffness is mainly due to the decreases in coordination number and the uniformity of contact force distribution during unloading process.
KeywordsDiscrete element method Micromechanics OCR Poisson’s ratio Small strain stiffness
The work presented in this paper is supported by National Key Research and Development Program (Grant No. 2016YFC0800200), National Natural Science Foundation of China (Grant Nos. 51308408, 41772283) and Fundamental Research Funds for the Central Universities. These supports are gratefully acknowledged.
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