沉积角对净砂宏微观力学特性影响的离散元分析

发布时间：2018-02-11 00:16

本文关键词： 离散元方法椭圆颗粒各向异性净砂双轴压缩试验　出处：《岩土力学》2016年02期 　论文类型：期刊论文

【摘要】：由颗粒定向排列导致的初始各向异性对净砂力学特性影响明显。为探究这一影响,首先采用自编的离散元软件生成4种不同沉积方向的椭圆颗粒净砂样,并分别对4种试样进行双轴压缩试验;其次,通过将离散元模拟结算与室内试验结果对比以验证该方法的可行性;最后,通过分析模拟结果研究沉积方向所产生的影响。结果表明:4种试样均出现应变软化及剪胀现象;随着沉积角δ的增加,试样具有由应变软化逐渐向应变硬化发展的趋势,试样的剪胀性逐渐减弱;在δ=0°时试样取得最大峰值内摩擦角和最大残余内摩擦角,且随着δ的增大试样的峰值内摩擦角先降低然后基本不变,残余内摩擦角逐渐减小;颗粒排列初始优势方向基本与沉积方向平行,但随着轴向应变的增大,颗粒排列优势方向逐渐向平行于加载面方向旋转,接触点的优势方向由最初垂直于沉积方向逐渐向垂直于加载面方向旋转,且这两种旋转的改变幅度随着沉积角δ的增大而增大;而强接触力的优势方向始终垂直于试样的加载面。
[Abstract]:The initial anisotropy caused by the directional alignment of particles has obvious influence on the mechanical properties of clean sand. In order to explore this effect, four kinds of elliptical pure sand samples with different deposition directions were generated by discrete element software. Four kinds of specimens were tested under biaxial compression. Secondly, the feasibility of the method was verified by comparing the simulation results of discrete elements with the results of indoor tests. By analyzing the simulation results, the influence of deposition direction is studied. The results show that the strain softening and shear dilatation appear in all of the four samples, and with the increase of deposition angle 未, the specimens have the tendency of developing from strain softening to strain hardening. The maximum peak internal friction angle and the maximum residual internal friction angle are obtained at 未 0 掳, and the peak internal friction angle decreases first and then remains unchanged with the increase of 未, and the residual internal friction angle decreases gradually. The initial dominant direction of particle arrangement is basically parallel to the direction of deposition, but with the increase of axial strain, the dominant direction of particle arrangement gradually rotates parallel to the direction of loading plane. The dominant direction of the contact point rotates gradually from the original vertical direction to the vertical direction of the loading plane, and the amplitude of the two rotation increases with the increase of the deposition angle 未. The dominant direction of the strong contact force is always perpendicular to the loading surface of the specimen.
【作者单位】：河海大学岩土工程系;同济大学土木工程防灾国家重点实验室;同济大学土木工程地下建筑与工程系;杭州钱江经济开发区建设局;
【基金】：国家杰出青年科学基金项目(No.51025932) 国家自然科学基金项目(No.51179128)~~
【分类号】：TU43

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