双轴压缩条件下碎石集料静力剪切特性研究

发布时间：2018-06-07 18:57

  本文选题：碎石路基 + 离散元　； 参考：《铁道学报》2014年06期

【摘要】：基于离散单元法,利用PFC2D内置Fish语言编制碎石集料双轴实验条件,结合计算机语言与PFC2D中Clump命令编制将球形单元转化为随机多边形块体单元的程序。通过对比室内大型三轴试验对数值模型进行参数标定与验证,在此基础上分析3种典型粒径碎石集料的应力-应变特性以及抗剪强度特性。结果表明,围压对集料的应力-应变特性影响明显。对于不同粒径的碎石集料而言,随着围压的增加,偏应力峰值增加而应力比减小;在本文选定的围压范围内碎石集料均呈现出先压缩最终剪胀的特性,围压越大,压缩量大,最终的剪胀越不明显;碎石集料的强度包络线为非线性,相同围压条件下的抗剪强度随着粒径的增大而增加;表征摩擦角随围压的增加而减小,相同围压下,粒径越大,表征摩擦角也越大。
[Abstract]:Based on the discrete element method and using PFC2D built-in Fish language to compile the biaxial experimental conditions of gravel aggregate, combined with the computer language and the Clump command in PFC2D, the program of transforming spherical element into random polygonal block element is compiled. The parameters of the numerical model were calibrated and verified by comparing the large scale triaxial tests in laboratory. On this basis, the stress-strain characteristics and shear strength characteristics of three typical grain-size aggregates were analyzed. The results show that the confining pressure has an obvious effect on the stress-strain characteristics of aggregates. For gravel aggregates with different particle sizes, with the increase of confining pressure, the peak value of deflection stress increases and the stress ratio decreases. In the range of confining pressure selected in this paper, the aggregate exhibits the characteristics of first compression and final shear expansion, the larger the confining pressure, the greater the compression. The ultimate shear expansion is less obvious, the strength envelope of gravel aggregate is nonlinear, the shear strength increases with the increase of particle size under the same confining pressure, the characteristic friction angle decreases with the increase of confining pressure, and the particle size increases with the same confining pressure. The larger the angle of friction is.
【作者单位】： 北京交通大学土木建筑工程学院;多年冻土区公路建设与养护技术交通行业重点实验室青海研究观测基地;
【基金】：国家自然科学基金(41371081,51378057) 国家基础研究计划(2012CB026104) 北京交通大学博士生创新基金(KCTB12023536)
【分类号】：TU45
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本文编号：1992407