孔隙水压力对饱和砂的剪切模量和阻尼比的影响

本文通过动三轴进行饱和砂的液化试验,考察三种砂的剪切模量和阻尼比随孔隙水压力变化的规律。由试验可知:①饱和砂的剪切模量与阻尼比随孔隙水压力的增加而降低;②在一般情况下,剪切模量、阻尼比与孔隙水压力及剪应变幅之间的关系可分别表示为可分离变量的函数:G（u,γ）=f（u）·Gm（γ）及λ（u,γ）=g（u）·λ_m（γ）,对试验所用的三种砂已给出表达式;③在接近液化时,橡皮膜对试验结果有较大的影响,应进行修正。

Influence of Pore Water Pressure on Shear Modulus and Damping Ratio of Saturated Sands

The dynamic characteristics of three kinds of Sands ware examined by means of dynamic triaxial tests. The results are summarized as follows: （1）shear modulus and damping ratio of saturated sands all decrease with the increase of pore water pressure. （ 2 ）shear modulus and damping ratio may be expressed as the functions of pore water pressure and shear-strain amplitude: G =f（u） &;#183; Gm（γ）, λ = g（u）&;#183;λm （λ）.From the test results the expressions of G-u and λ-u under the test condition are derived by separating variable. （ 3 ）the effect of sample films on test results is studied and analysed. With the effect of films modified, both shear modulus and damping ratio of the soil during liquefaction may be considered to approach zero.