考虑颗粒破碎的砂土临界状态特性描述

发布时间：2018-08-30 11:53

【摘要】：近年来,随着土石坝和高填方等工程的兴建,粒状土得到了广泛的应用。粒状土在高应力作用下会发生颗粒破碎的现象相当严重,因此粒状土的颗粒破碎问题不容忽视。为了更合理地描述颗粒破碎对粒状土中砂土力学特性的影响,首先分析砂土试验结果,得出了砂土颗粒分别在平均正应力和剪应力作用下的破碎特性。其次,基于UH(unified haedening,统一硬化)模型,引入可以表示砂土压缩破碎和剪切破碎的相关参数,建立了可以考虑颗粒破碎的砂土本构模型。该模型不仅能够反映砂土的剪胀、剪缩、应变硬化和软化等特性,而且可以反映在平均正应力的作用下,不同的压缩曲线最终会归一的特点,同时还能够反映剪应力作用下砂土临界状态线下移的现象。最后,使用模型预测了Lade的常规三轴试验,模型预测结果与试验结果符合良好,说明该模型能够合理地描述砂土的力学特性。
[Abstract]:In recent years, granular soil has been widely used with the construction of earth-rock dams and high-fill projects. Particle breakage occurs seriously in granular soil under high stress, so the particle breakage of granular soil can not be ignored. In order to describe more reasonably the effect of particle breakage on the mechanical properties of sand soil in granular soil, the results of sand soil test are analyzed, and the breakage characteristics of sand particles under the action of average normal stress and shear stress are obtained. Secondly, based on the UH (unified haedening, uniform hardening model, the constitutive model of sand can be considered by introducing the relevant parameters which can represent the compression and shear breakage of sand. The model can not only reflect the properties of sand such as dilatancy, shearing shrinkage, strain hardening and softening, but also reflect the characteristics that the different compression curves will be homogenized under the action of average normal stress. At the same time, it can also reflect the phenomenon that the critical state line of sand soil moves down under the action of shear stress. Finally, the conventional triaxial test of Lade is predicted by using the model, and the predicted results are in good agreement with the experimental results, which shows that the model can reasonably describe the mechanical properties of sand.
【作者单位】：北京航空航天大学交通科学与工程学院;
【基金】：国家重点基础研究发展计划项目(2014CB047001) 国家自然科学基金项目(51179003,11272031)
【分类号】：TU441

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