Effects of loading frequency and specimen size on the liquefaction resistance of clean sand

초록

This study investigates the effects of loading frequency ( f ) and specimen size on the liquefaction resistance of clean sand. A series of cyclic direct simple shear tests were conducted on Jumunjin sand with varying consolidated relative densities (40% and 80%), f values (0.05, 0.10, and 0.20 Hz), and diameter to height ( D/H ) ratios (3.63, 3.18, 2.82, and 2.54). The results demonstrated the significant influence of f and D/H ratio on the number of cycles to liquefaction ( N cyc - liq ) and the cyclic resistance ratio ( CRR 15 ). It was observed that increasing f linearly increased N cyc - liq . Increasing the specimen height also led to higher N cyc - liq values irrespective of the f or relative density. Moreover, a positive correlation between CRR 15 and f indicated that higher f yielded higher CRR 15 . This relationship was more pronounced in dense sand than in loose sand. Specimen height also significantly affected CRR 15 , with increasing the specimen height resulting in higher CRR 15 values. Furthermore, the effect of f on CRR 15 was less significant compared to the influence of specimen height. The effect of f on the normalized cyclic resistance ratio ( NCRR ) was relatively negligible for loose sand but more substantial for dense sand depending on the D/H ratio. Data analysis revealed that the NCRR generally decreases as the D/H ratio increases. An interpolation formula was provided to calculate the NCRR based on the D/H ratio regardless of the f and relative density.

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