Effect of Particle Size Distribution on Monotonic Shear Strength and Stress-Dilatancy of Coarse-Grained Soils
Effect of Particle Size Distribution on Monotonic Shear Strength and Stress-Dilatancy of Coarse-Grained Soils
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DOI：
10.1061/9780784484678.031
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发表时间：
2023-03
期刊：
影响因子：
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通讯作者：
Mandeep Singh Basson;Alejandro Martinez;J. DeJong
中科院分区：
文献类型：
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作者：
Mandeep Singh Basson;Alejandro Martinez;J. DeJong
天然土壤沉积物可以由大小不一的颗粒组成。在目前的实践中，对粗粒土的抗剪强度和应力-剪胀特性的评估是基于对差级配砂开发的方法，没有明确考虑级配的差异。本文研究了粒径范围对差级配至好级配土单调抗剪强度和应力-剪胀响应的影响。利用三维离散元法（DEM），评估了常用砂基应力-剪胀框架在一系列等级中的适用性。在均匀系数（CU）在1.9到6.9之间变化的情况下，采用球团来精确模拟样品上的颗粒形状。这些试样在不同的相对密度和围应力下进行了各向同性固结排水三轴压缩，目的是分离颗粒大小分布和颗粒形状的影响。评价了不同级配下试件的峰值抗剪强度、临界抗剪强度和剪胀响应。在相同的状态参数下，随着粒径范围的增大，抗剪强度和膨胀速率均增大。然而，临界状态线向下移动，其斜率随着CUis的增加而减小。将DEM结果与Bolton的应力-扩容关系进行比较，以突出使用干净的砂基框架在捕获分级良好的土壤行为方面的不足。
Natural soil deposits can consist of particles with a wide range of sizes. In current practice, the assessment of shear strength and stress-dilatancy behavior of coarse-grained soils is based on methods developed for poorly graded sands, without explicit consideration for differences in gradation. This paper investigates the influence of the range of particle sizes on the monotonic shear strength and the stress-dilatancy response of poorly- to well-graded soils. Using the 3D discrete element method (DEM), the applicability of commonly used sand-based stress-dilatancy frameworks is assessed for a range of gradations. This DEM investigation employs clumps of spheres to accurately simulate the particle shapes on specimens with coefficients of uniformity (CU) varying between 1.9 and 6.9. These specimens were subjected to isotropically consolidated drained triaxial compression at various relative densities and confining stresses with the objective of isolating the effects of particle size distribution from those of particle shape. The peak and critical state shear strengths and the dilatancy responses of the specimens with different gradations are evaluated. For the same state parameter, the results indicate an increase in the shear strength and rate of dilation as the range of particle sizes increases. However, the critical state line shifts downward, and its slope decreases as CUis increased. The DEM results are compared to Bolton’s stress-dilatancy relationship to highlight the inadequacies of using clean sand-based frameworks in capturing the behavior of well-graded soils.