砂土滑动与转动破坏模式的离散元分析

Discrete Element Analysis of Sand in Sliding and Rotational Destruction Mode

砂土的离散型使其内部颗粒在外载荷作用下会发生滑动与转动两种变形,为了直观量化两种变形对其力学特性及抗剪强度的影响,建立了砂土的三轴试验离散元模型,探究两种破坏模式在常规三轴试验中的表现,从而揭示砂土材料在两种破坏模式下表现出的相关规律。结果表明:砂土在仅发生滑动变形时,抗剪强度主要取决于其摩擦系数,且随着摩擦系数的增大急剧上升;砂土在仅发生滚动变形时,其抗剪强度与摩擦系数基本无关;在两种变形共存时,其力学特性偏向与滚动变形的特征,且抗剪强度与上述两种极端变形相比得到极大降低。土的强度是分析计算路基及土工建筑物稳定性的重要力学参数,研究结果为重新认识砂土强度提供了依据。

Sand structure of the discrete type makes its internal particles under external load occur such two kinds of deformation as sliding and rotation,in order to visually quantify the two deformation on its mechanical properties and shear strength,the sand triaxial test discrete element model was established,the performance of the two failure modes in conventional triaxial tests was explored to reveal the relevant laws of sand materials in the two failure modes.The results show that the shear strength of sand mainly depends on the friction coefficient when it is only sliding,and it increases sharply with the increase of friction coefficient.When the sand is rolling,the shear strength basically has no relations with friction coefficient The mechanical properties of the two kinds of deformation are biased and the characteristics of rolling deformation when the two kinds of deformation coexist,and the shear strength is greatly reduced compared with the two extreme deformations mentioned above.The strength of soil is an important mechanical parameter for analyzing the stability of subgrade and geotechnical building.The results of the study have a certain guiding effect on recognizing the strength of sand.