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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。
In recent years, with the construction of earth-rock dams and high fill and other projects, granular soil has been widely used. Granular soil under high stress will occur under the phenomenon of particle crushing is quite serious, so the particle crushing of granular soil can not be ignored. In order to describe the effect of particle crushing on the mechanical properties of sand in grained soil more reasonably, the sand test results were firstly analyzed and the crushing properties of sand particles under the mean normal stress and shear stress were obtained respectively. Secondly, based on the unified hardening (UH) model, the relevant parameters which can represent the compression and shear of sand are introduced, and the constitutive model of sand which can consider the particle breakage is established. The model can not only reflect the characteristics of sand dilatancy, shear shrinkage, strain hardening and softening, but also reflect the characteristics of different compressive curves that will eventually be normalized under the mean normal stress, and also reflect the effect of shear stress Under the critical state of sand down line phenomenon. Finally, the model was used to predict Lade’s conventional triaxial test. The model predictions are in good agreement with the experimental results, which shows that the model can reasonably describe the mechanical properties of sand.