On the influence of grain shape on the cumulative deformations in sand under drained high-cyclic loading
On the influence of grain shape on the cumulative deformations in sand under drained high-cyclic loading
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DOI：
10.1016/j.sandf.2018.11.001
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发表时间：
2019-02
影响因子：
3.7
通讯作者：
T. Wichtmann;T. Triantafyllidis;L. Späth
中科院分区：
文献类型：
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作者：
T. Wichtmann;T. Triantafyllidis;L. Späth
在排水循环三轴试验中，研究了颗粒形状和表面特征显著不同但粒度分布曲线相同的三种颗粒材料（玻璃珠、近圆形颗粒天然砂和角状颗粒碎砂）的累积响应。对于每种材料，进行了100，000次循环和不同振幅、密度、平均平均压力和平均应力比的多次测试。在玻璃珠和天然砂的情况下，残余应变累积速率与应力或应变幅之间存在近似平方关系（ε今acc <$ε ampl 2），而在碎砂的情况下，残余应变累积速率与应力或应变幅之间存在近似成比例的关系（ε今acc <$ε ampl 2）。三种试验材料的累积响应的最大差异是关于压力依赖性的ε ~ acc。对于玻璃珠和天然砂（不太明显），残余应变累积率下降，平均平均压力，而相反的趋势，得到的碎砂。在小的压力下，玻璃珠的残余应变比天然砂，特别是碎砂大得多，而在较大的压力下，累积应变的这些差异几乎减小。独立的形状和颗粒的表面特性，它被证实，平均应力比是控制参数的循环流动规则。最后，对Niemunis等人提出的高周波积累（HCA）模型的参数进行了讨论。（2005）进行了分析，考虑到晶粒形状参数（纵横比，圆度）从自动晶粒形状分析。
The cumulative response of three granular materials with significantly different grain shape and surface characteristics (glass beads, natural sand with subrounded grains and crushed sand with very angular particles) but identical grain size distribution curve has been studied in drained cyclic triaxial tests. For each material, several tests with 100,000 cycles and different amplitudes, densities, average mean pressures and average stress ratios have been performed. In case of glass beads and natural sand, an approximately square relationship between the residual strain accumulation rates and stress or strain amplitude was found (ε ̇ a c c∼ ε a m p l 2), while an almost proportional dependence was measured for the crushed sand (ε ̇ a c c∼ ε a m p l). The largest differences in the cumulative response of the three tested materials were observed regarding the pressure-dependence of ε ̇ a c c. For glass beads and (less pronounced) for natural sand, the residual strain accumulation rates decreased with average mean pressure, while the opposite tendency was obtained for the crushed sand. At small pressures, the residual strains were much larger for the glass beads than for the natural sand and particularly the crushed sand, while these differences in the accumulated strains almost diminished at larger pressures. Independent of the shape and the surface characteristics of the particles, it was confirmed that the average stress ratio is the governing parameter of the cyclic flow rule. Finally, the parameters of the high-cycle accumulation (HCA) model proposed by Niemunis et al.(2005) were analyzed considering the grain shape parameters (aspect ratio, circularity) obtained from an automated grain shape analysis.