最大动态剪力模数次增加率之预测

正规化最大动态剪力模数次增加率Ｎ＿ｇ之观念虽然已被提出，但是其影响因素之精确指标仍待后人研究。因此，本文深入探讨粘性土壤在现场有效覆土压力长期作用下，时间效应对最大动态剪力模数Ｇ＿（ｍａｘ）之影响，并与剪力波速回归公式作比较，以期达到预测Ｎ＿ｇ值之目标。在一般物理性质对时间效应之影响研究中，Ｎ＿ｇ值有随塑性指数Ｉ＿ｐ值增加之趋势，而平均颗粒粒径Ｄ＿（５０）愈小时，Ｎ＿ｇ值愈大，且重模试体之Ｎ＿ｇ值较原状试体为小。由本文之Ｎ＿ｇ－Ｉ＿ｐ－Ｃ值之关系可知，粘土含量Ｃ相同时，若Ｉ＿ｐ值愈大，则Ｎ＿ｇ愈大。而Ｎ＿ｇ－Ｉ＿ｐ－Ｃ＿ａ值三者之关系中，若二次压缩指数Ｃ＿ａ值相同，则Ｉ＿ｐ值愈大时，Ｎ＿ｇ值愈大。

Prediction of Secondary Increment Rate of Dynamic Shear Modulus

The idea of“the secondary increment rate of dynamic shear modulus”has been proposed for a long while.However,the influence factors of this rate is still under investigation,Therefore,the “long-term time effect”onthe maximum dynamic shear modulus G_max under the effective overburden pressure was studied in this article, Theregression equations of shear wave velocity were examined as well.The secondary ineronrent of normalized shearmodulus N_g was found increasing as the value of plastic index I_P increased. But,the N_g decreased as the 50% parti-cle size D₅₀ inereased. The N_g of an undisturbed sample is larger that that of a remolded sample in the relationshipof N_g-D₅₀. From the N_g-I_p-C relation,the N_g was becoming larger along with the I_p in the same amount ofclay C. With the same value of secondary compression index C_a,the N_g increased as the I_p increased in the N_g-I_p-C_a relationships.