改良粗粒土填料大型三轴试验

发布时间：2018-02-28 09:25

本文关键词： 填料复合砾级配改良大型三轴实验 Duncan-Chang模型　出处：《中南大学学报(自然科学版)》2015年02期 　论文类型：期刊论文

【摘要】：为了解路基填料级配改良后的物理力学特性,向素土中掺加3种粒径范围内不同质量比的碎石,制成4种具有不同颗粒级配的改良填料,采用大型三轴剪切仪对素土和复合砾进行三轴剪切试验。在试验基础上提出轴向应变与侧向应变的二次函数关系,建立体积应变与轴向应变的函数方程,并对试样三轴试验的体积应变和切线泊松比进行预测。研究结果表明:粗颗粒质量分数较高的试料在低围压下出现剪胀现象,在高围压下出现剪缩现象;在低围压下,随着粗颗粒质量分数升高,试样体变由剪缩趋势逐渐转为剪胀趋势;应用邓肯-张模型并求得其参数,得出试样的黏聚力c、内摩擦角φ及切线弹性模量Et随粗颗粒质量分数的增加而增大;邓肯-张模型不能很好地反映粗粒土填料的变形特性;预测结果表明改进模型能较合理地描述粗颗粒土填料的体积应变特性。
[Abstract]:In order to understand the physical and mechanical properties of the improved subgrade filler gradation, four kinds of improved fillers with different particle gradation were prepared by adding three kinds of gravel with different mass ratios in the particle size range to the plain soil. The triaxial shear tests of plain soil and composite gravel were carried out by using a large triaxial shear apparatus. On the basis of the tests, the quadratic function of axial strain and lateral strain was put forward, and the function equation of volume strain and axial strain was established. The volume strain and tangent Poisson's ratio of triaxial test are predicted. The results show that the specimen with higher coarse particle mass fraction has shear dilatation at low confining pressure, shearing shrinkage at high confining pressure, and shearing shrinkage at low confining pressure. With the increase of coarse particle mass fraction, the shear shrinkage trend of the sample is gradually changed to the shear expansion trend, and the Duncan-Chang model is applied and its parameters are obtained. The results show that the cohesive force c, the angle of internal friction 蠁 and the tangent elastic modulus E _ t increase with the increase of coarse particle mass fraction, but the Duncan-Chang model can not well reflect the deformation characteristics of coarse grained soil filler. The prediction results show that the improved model can reasonably describe the volumetric strain characteristics of coarse grained soil fillers.
【作者单位】：中南大学土木工程学院;中南大学高速铁路建造技术国家实验室;
【基金】：国家自然科学基金资助项目(51378514) 高速铁路建造技术国家工程实验室基金资助项目(2008G031-Q)~~
【分类号】：TU411

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