Effect of clay invasion on shear behavior and dilatancy of unbound aggregate subbase
Effect of clay invasion on shear behavior and dilatancy of unbound aggregate subbase
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DOI：
10.1016/j.trgeo.2015.12.001
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发表时间：
2016-03-01
影响因子：
5.3
通讯作者：
Zhang, Jiasheng
中科院分区：
文献类型：
--
作者：
Chen, Xiaobin;Zhang, Jiasheng
未结合的骨料底基层偶尔会因细路基土的侵入或泵送而被污染，并且评估粘土侵入对剪切和膨胀行为的影响变得具有实际价值。本文介绍了粘土侵入对用作底基层填料的测试花岗岩骨料的剪切和膨胀行为影响的实验研究。为了加深对膨胀的理解，对饱和条件下的骨料-粘土混合物进行了大型三轴试验（TX）试验。粘土侵入未结合的骨料底基层会导致峰值强度和临界强度下降，强度损失 20-30%。粘土包裹体和增加的围压都以抑制膨胀的形式降低了体积应变。对于混合物，剪胀角常数参数与剪应力比之间观察到线性关系。提出了膨胀率和剪应力比的双曲线模型，并确定了参数 a、b、k。结果显示实验图和建模趋势之间具有良好的一致性。这些发现将有利于非粘合骨料材料在路面中的应用。 (C) 2016 Elsevier Ltd. 保留所有权利。
Unbound aggregate subbase is occasionally fouled by the invading or pumping of fine sub-grade soils, and evaluation of clay invasion on shear and dilative behaviors become practically valuable. This paper presents an experimental investigation of the effect of clay invasion on shear and dilative behavior of a tested granite aggregate, used as subbase fill. To deepen the understanding of dilation, the large-scale triaxial tests (TX) tests were conducted on aggregate-clay mixtures in saturated conditions. The invasion of clay into unbound aggregate subbase leads to decreasing peak strength and critical strength, with a 20-30% strength loss. Both the clay inclusion and the increasing confining pressure decrease the volumetric strain in the form of dilation suppression. For the mixtures, the linear relationship was observed between the constant parameter of dilatancy angle and shear stress ratio. A hyperbolic model was proposed for the dilation rate and shear stress ratio, and the parameters, a, b, k, were identified. Results show a good agreement between the experimental diagrams and the modeling trends. The findings would benefit the application of unbound aggregate materials in pavements. (C) 2016 Elsevier Ltd. All rights reserved.