Effect of specimen preparation methods on the maximum dynamic shear modulus of sand

The maximum dynamic shear modulus (G_dmax) of sand is one of the key indicators characterizing its dynamic properties, which plays a crucial role in seismic safety evaluations of related structures. However, due to complexities in remolded specimen preparation methods and experimental gradations, the understanding of influencing factors on G_dmax remains inconsistent and requires ongoing research. This study integrated an improved wave velocity testing device into a medium-sized triaxial apparatus to conduct shear wave velocity tests on remolded sand specimens prepared using various methods (moist tamping, dry tamping, and air pluviation), investigating the variation patterns of G_dmax. The results demonstrate that: Specimens prepared by different methods show minimal differences in void ratios under identical consolidation stress conditions. Compared with other methods, moist tamping specimens achieve faster fabric stabilization under low consolidation stresses and exhibit stronger resistance to volumetric deformation under high consolidation stresses. The preparation method significantly affects G_dmax under low consolidation stresses, with maximum relative differences reaching approximately 20% (moist tamping > dry tamping > air pluviation). These differences gradually diminish with increasing consolidation stress. Although introducing void ratio parameters significantly improves the prediction accuracy of G_dmax, parameters corresponding to different specimen preparation methods still show notable differences, with maximum relative discrepancies exceeding 10%.