Small-strain stiffness of sand subjected to stress anisotropy
Small-strain stiffness of sand subjected to stress anisotropy
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DOI：
10.1016/j.soildyn.2016.06.004
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发表时间：
2016-09-01
影响因子：
4
通讯作者：
Khalili, Nasser
中科院分区：
文献类型：
--
作者：
Payan, Meghdad;Khoshghalb, Arman;Khalili, Nasser
通过小应变剪切模量表示的小应变下土壤的刚度对于评估各种应力状态下的地质结构的变形至关重要。虽然以往对砂土小应变剪切模量的研究大多集中在各向同性应力状态，但岩土工程中存在无数土体处于各向异性应力状态的情况。在本研究中，利用在各向同性和各向异性载荷条件下对饱和砂样品进行的一组综合弯曲单元测试的结果，评估了应力各向异性对砂的小应变剪切模量 (G(max)) 的影响。结果表明，在各向异性载荷条件下砂的小应变剪切模量比在给定平均有效应力下受到各向同性应力状态的砂的小应变剪切模量更大。研究还表明，与颗粒相对圆形和球形的均匀砂相比，对于形状不规则且粒度分布较宽的砂，应力各向异性对砂的小应变剪切模量的影响更为明显。根据实验结果，开发了一种新的 G(max) 模型，该模型在预测受应力各向异性作用的砂的小应变剪切模量时考虑了粒度特征和颗粒形状的贡献。 (C) 2016 Elsevier Ltd. 保留所有权利。
Stiffness of soils at small strains expressed through the small-strain shear modulus is critical for the evaluation of deformations of geo-structures subjected to a variety of stress states. While most of the previous studies of small-strain shear modulus of sands have focused on the isotropic stress state, there exist innumerable situations in geotechnical engineering in which the soil is under an anisotropic stress state. In this study, the influence of stress anisotropy on the small-strain shear modulus (G(max)) of sands is evaluated using the results of a comprehensive set of bender element tests conducted on saturated sand samples under isotropic and anisotropic loading conditions. It is shown that the small-strain shear moduli of sands under anisotropic loading conditions are greater in magnitude than those subjected to isotropic stress states at a given mean effective stress. It is also shown that the influence of stress anisotropy on the small-strain shear modulus of sands is more pronounced for sands with irregular in shape grains and wider grain size distribution in comparison to uniform sands of relatively rounded and spherical grains. Based on the experimental results, a new G(max), model is developed which incorporates the contribution of grain size characteristics and particle shape in the prediction of the small-strain shear modulus of sands subjected to stress anisotropy. (C) 2016 Elsevier Ltd. All rights reserved.