基于大型直剪的砂土及其筋土界面剪胀性研究

发布时间：2018-04-14 17:26

  本文选题：剪胀特性 + 三向土工格栅　； 参考：《施工技术》2015年S2期

【摘要】：采用大型直剪仪,对三向土工格栅加筋北京地区砂土的界面剪胀特性进行了试验研究,通过大型直剪试验模拟砂土加筋时的剪切作用过程,得出了以下结论:1砂土在剪切过程中都是由短暂的剪缩效应发展为稳定的剪胀效应;2在低含水率时砂土的剪胀效应较明显,随着含水率的增加,剪胀效应有一个先降低后升高的过程,当含水率增大到12%且竖向应力为215~323k Pa时,砂土的剪胀效应会超过含水率为2.5%时的剪胀效应;3当竖向压力小,砂土较为松散时,砂土基本没有剪胀效应,但是随着竖向压力的增大,砂土的剪胀效应经历从无到有并且是先升高后降低的过程。当竖向应力在215~323k Pa时剪胀效应最显著;4格栅加筋可以降低砂土的剪胀效应,并且压力越大降低效果越明显。
[Abstract]:In this paper, the interfacial shear dilatancy of sand reinforced by three direction geogrid in Beijing area is studied by using a large direct shear apparatus, and the shear process of reinforced sand is simulated by large scale direct shear test.The following conclusions are drawn: the shear dilatation effect of sand with low moisture content is obvious, and the shear dilatation effect is obvious with the increase of water content, and the shear dilatation effect of sand is changed from the transient shear shrinkage effect to the stable shear dilatancy effect in the shear process.When the moisture content increases to 12% and the vertical stress is 215323kPa, the shear expansion effect of sand will exceed that of 2.5 when the vertical pressure is small and the sand is looser.There is no shear expansion effect in sand, but with the increase of vertical pressure, the shear expansion effect of sand goes from scratch to existence and then decreases.When the vertical stress is at 215223kPa, the shear expansion effect is the most obvious and the shear expansion effect can be reduced with the reinforcement of the grid, and the greater the pressure is, the more obvious the shear expansion effect is.
【作者单位】： 北京工业大学城市与工程安全减灾教育部重点实验室;
【基金】：高等学校博士学科点专项科研基金(20121103110022) 北京工业大学研究生科技基金(ykj-2014-10632)
【分类号】：TU411
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本文编号：1750331