粗粒土剪胀性大型三轴试验研究

发布时间：2018-05-07 02:03

本文选题：粗粒土 + 三轴试验　；参考：《岩土力学》2014年11期

【摘要】：剪胀性是土体显著区别于一般弹性材料的基本特性,与土体的强度和变形特性密切相关。通过4组不同初始密度的塔城砂砾石常规大型三轴试验,研究剪胀性对粗粒土强度和变形特性的影响。试验结果表明,(1)若体变速率(体变和轴向应变均以压缩为正)先从正值减小到负值并达到最小值,随后又有所增大但仍小于0,则应力-应变曲线为软化型,在比值为最小值时土体剪胀性最大,对应于峰值强度,若体变速率从某一正值单调减小并一直大于0,则应力-应变曲线为硬化型;(2)体变变化趋势取决于剪胀性和压缩性的大小,剪切后期若剪胀速率大于压缩速率,则体变先压缩后膨胀,应力-应变曲线呈软化型,反之若剪胀速率小于压缩速率,则体变一直是压缩的,应力-应变曲线呈硬化型。研究结果对于加深认识粗粒土的强度和变形特性具有重要意义。
[Abstract]:Shear dilatancy is the basic characteristic of soil which is obviously different from the general elastic material and is closely related to the strength and deformation of soil. The influence of shear dilatancy on the strength and deformation of coarse grained soil was studied by four groups of conventional triaxial tests with different initial densities of sand and gravel in Tacheng. The experimental results show that the stress-strain curve is softened if the volume variation rate (both volume strain and axial strain are compressible as positive) from positive to negative and reach the minimum value, and then increase but still less than 0, then the stress-strain curve is softened. When the ratio is the minimum, the shear dilatancy of the soil is the largest, corresponding to the peak strength. If the volume variation rate decreases from a certain positive monotone and is always greater than 0, then the stress-strain curve is the hardening type and the variation trend of the body deformation depends on the magnitude of the shear expansion and compressibility. At the later stage of shear expansion, if the expansion rate is greater than the compression rate, the volume deformation first compresses and then expands, and the stress-strain curve is softened. Otherwise, if the shear expansion rate is less than the compression rate, the volume deformation is always compressed, and the stress-strain curve is hardening. The results are of great significance for further understanding the strength and deformation characteristics of coarse-grained soil.
【作者单位】：南京工程学院建筑工程学院;长江科学院水利部岩土力学与工程重点实验室;
【基金】：长江科学院开放研究基金资助项目(No.CKWV2013205/KY) 南京工程学院校级科研基金项目资助(No.YKJ201330)
【分类号】：TU443;TU411

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