粘粒含量对饱和砂土动孔隙水压力的影响

Effect of the Clay Particles on the Dynamic Pore Pressure of a Saturated Sand

用双向电磁振动三轴试验仪进行了动三轴试验,研究了粘粒含量为0%、10%、20%、30%、40%、50%的饱和砂土动孔压的变化规律。按轴向应变ε_f=5%为破坏标准,当土体达到破坏后,取每个振次对应的峰值孔压u_p。研究表明：在粘粒不超过20%时,饱和砂土的孔压u_p增长速率随着粘粒含量的增加而增加。粘粒超过20%后,饱和砂土的孔压u_p开始抑制,粘粒大于40%时孔压u_p得到完全抑制,破坏后的峰值动孔压值基本不变。应用现有的孔隙水压力发展模型对本次试验结果的数据进行了拟合,并对参数进行分析。

The effect of clay contents on the dynamic pore pressure in the saturated sands were studied with dynamic triaxial tests.Samples with clay contents of 0%,10%,20%,30%,40% and 50% were prepared for the tests.The failure criterion of the triaxial tested samples was set to have an axial strain of 5%.After the sample was failed,the peak pore pressure values that correspondent to each cycle were recorded.The results indicate that,when the clay content is less than 20%,the ratio of peak pore pressure increase in the saturated sand increases with the clay contents.Therefore,the clay content helps the peak pore pressure increase.When the clay content is more than 20%,the peak pore pressure increase ratio is reduced by the increase of clay content.When the clay content is greater than 40%,the increase of pore water pressure is completely blocked by the clay content,an approximately constant peak pore pressure was observed after the failure.The regression analyses were also performed on the curve fitting of the current parameters.