低含水量粘土的加载速率效应与蠕变变形

Load-rate effect and creep deformation of clay with low water content

  • 摘要: 通过对低含水量藤森粘土(Fujinomori clay)试样的单向固结试验,研究了低含水量粘土的加载速率效应与蠕变变形。所采用的藤森粘土土样有湿润(含水量小于15%)、风干(含水量小于4.5%)与烘干(含水量小于1%)3种。试验中,应变率逐步改变,同时进行了蠕变及加、卸载试验以及小幅度的循环加载试验。试验结果表明:湿润土样、风干土样与烘干土样都有明显的加载速率效应与蠕变变形;在大范围的卸载-重复加载过程中,蠕变变形会由卸载初期的正变形逐步发展为后期的负变形,在这个发展过程中存在着中性点(即蠕变为零,或者无蠕变的点);藤森粘土的加载速率效应随含水量的降低有所降低,即湿润藤森土样的加载速率效应更明显。

     

    Abstract: Resultsof one dimensional compression tests of wet,air-dried and oven-dried Fujinomori clay were presented in this paper.Water content of wet,airdried and oven-dried clay specimen was smaller than 15%,4.5% and 1% respectively.In all tests,axial strain rate was changed stepwise many times and drained creep tests were performed several times during monotonic loading at a constant strain rate.Global unloading-reloading was applied,during which creep loading tests were performed several times.Test results show that: All specimens of Fujinomori clay with low water content show noticeable load-rate effect and creep deformation;During global unloading,creep deformation changes from positive to negative continuously,i.e.the neutral point(zero creep deformation or no creep deformation point) exists in global unloading part of strain-stress curve;load-rate effect of Fujinomori clay with higher water content are more significant than that with low water content.

     

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