三轴试样高径比对试验影响的颗粒流数值模拟

发布时间：2018-04-29 23:34

本文选题：粗粒土 + 高径比　；参考：《中南大学学报(自然科学版)》2015年07期

【摘要】：基于离散元软件PFC3D,通过编制可破碎的颗粒簇单元,模拟三轴试验中不同高径比试样应力应变特性的差异,通过比较强度和变形参数差异探讨适合粗粒土的高径比。研究结果表明:高径比越小,试验得到的内摩擦角越大,围压越大,由于颗粒破碎导致的内摩擦角越小;满足莫尔-库仑准则破坏面的最小高径比随着围压的增加而减小,但都大于现在室内试验常用的高径比;峰值强度随着高径比的增加而减小,随着围压的增大,不同高径比之间峰值强度相对误差减小;割线模量与高径比呈折线形关系;不同高径比之间割线模量的差异随高径比范围的不同而不同,且最小高径比的割线模量与现在室内试验常用高径比的割线模量在低围压下差异较大。依据模拟结果,认为粗粒土的三轴试样高径比应大于2.5。
[Abstract]:Based on the discrete element software PFC3D, the differences of stress-strain characteristics of samples with different aspect ratios in triaxial tests were simulated by compiling broken particle cluster units. The ratio of height to diameter suitable for coarse grained soil was discussed by comparing the strength and deformation parameters. The results show that the smaller the ratio of height to diameter, the greater the angle of internal friction and the larger the confining pressure, the smaller the angle of internal friction due to particle breakage, and the smaller the minimum ratio of height to diameter of the failure surface satisfying the Mohr Coulomb criterion decreases with the increase of confining pressure. The peak strength decreases with the increase of the ratio of height to diameter, and decreases with the increase of confining pressure, and the relative error of peak strength between different ratio of height to diameter decreases, the relationship between Secant modulus and ratio of height to diameter is broken. The difference of Secant modulus between different aspect ratio is different with the range of height to diameter ratio, and the Secant modulus of the minimum aspect ratio is quite different from that of the height to diameter ratio commonly used in laboratory tests under low confining pressure. According to the simulation results, it is considered that the ratio of height to diameter of triaxial specimen should be greater than 2.5.
【作者单位】：河海大学岩土力学与堤坝工程教育部重点实验室;河海大学岩土工程科学研究所;香港理工大学土木工程系;
【基金】：国家重点基础研究发展规划(973计划)项目(2013CB036404) 高等学校博士学科点专项科研基金资助项目(20110094110002) 高等学校学科创新引智计划项目(B13024)~~
【分类号】：TU411

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