固结比对砂土动剪切模量及地表反应谱的影响

采用共振柱试验方法，研究了固结比对砂土最大动剪切模量以及对动剪切模量比与剪应变非线性关系的影响。通过土层地震反应计算，初步给出了这种影响对地表反应谱作用的估计。对福建标准砂和哈尔滨砂进行了系统试验，提出了计算不同固结比砂土最大动剪切模量的建议公式，公式显示固结比kc>1、最大动剪切模量较kc=1时的增长程度明显比Hardin公式要大。同时，给出了固结比对动剪切模量比与剪应变非线性关系及其对地表反应谱的影响。结果表明，固结比对砂土动剪切模量比与剪应变非线性关系有一定影响。随着固结比增加，模量比非线性关系曲线有一定提高，在强地震动作用下的土层反应分析中应考虑实际固结比的影响。

Effects of consolidation ratios of sands on dynamic shear modulus and response spectrum of soil surface

The effects of the consolidation ratios on the maximum dynamic shear modulus and the dynamic shear modulus versus the shear strain of sands are presented by using the resonant column method. The effects of the dynamic shear modulus versus the shear strain under different consolidation ratios on spectrum of surface ground motion are evaluated by the soil layer response calculation. The Fujian’s standard sand and Harbin’s sand of China are employed in the tests. The recommended formula considering the effects of the consolidation ratios on the maximum dynamic shear modulus of sands is given. The new formula indicates that the increasing degree of the maximum dynamic shear modulus due to kc>1 is significantly larger than that described by Hardin and Black’s formula. The effects of the consolidation ratios on dynamic shear modulus versus the shear strain and surface ground motion are demonstrated. The results indicate that the dynamic shear modulus versus the shear strain increases with increasing of the consolidation ratios; and the effects of the consolidation ratios on dynamic shear modulus versus the shear strain should be considered for the incidence of the strong shock.