摘要
为探究细粒含量f_c、相对密度D_r以及初始有效围压σ'3c对饱和砂-粉混合料小应变剪切模量G_(max)的影响,对具有不同f_c,D_r和σ'_(3c)的混合料开展了一系列弯曲元试验.试验发现:随着f_c的增加,Dr=35%,50%的混合料的G_(max)先减小后略有增大,Dr=60%的混合料的G_(max)逐渐减小;当Dr相同时,具有不同fc的混合料的G_(max)都随σ'_(3c)的增大而增大,且G_(max)随σ'_(3c)的增长速率基本保持不变;当σ'_(3c)相同时,G_(max)随孔隙比的增大而减小,f_c对G_(max)随孔隙比增大而减小的速率有明显影响.分析表明:当f_c确定时,Hardin模型能很好地预测G_(max),但随f_c的增大,模型参数A先减小后增大;考虑f_c,e和σ'_(3c)对G_(max)影响的修正Hardin模型能较好地预测不同类别砂-粉混合料的G_(max),且G_(max)预测值的误差基本小于10%.
In order to investigate the influences of the fine content fc,relative density D_r,and initial effective confining pressure σ'_(3c) on the small-strain shear modulus G_(max) of sand-silt mixtures,a series of bender element tests were performed on saturated sand-silt mixtures with various fc,Dr and σ'_(3c).The test results show that,as f_c increases,G_(max) of the mixtures with D_r = 35% or 50% first decreases and then increases slightly,while G_(max) for D_r = 60% case presents a decreasing tendency. σ'_(3c) causes an increase in G_(max) with different f_c at a given Dr,and the growth rate of G_(max) with σ'_(3c) remains basically unchanged. In addition,G_(max) decreases with the increase of the void ratio at a fixed σ'_(3c),and f_c has a strong influence on the decreasing rate of G_(max) at a constant σ'_(3c). The testing results reveal that Gmax for a specified f_c case can be estimated reasonably using the Hardin model. However,as f_c increases,the best-fitting parameter A of the Hardin model first decreases and then increases. The modified Hardin model,considering the influences of fc,σ'_(3c) and e,can be used to predict Gmax for different types of sand-silt mixtures,and the errors of the predicted Gmax are basically less than 10%.
引文
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