橡胶纤维-砂混合料力学特性的离散元三轴试验研究

Triaxial shear test of mechanical characteristics on rubber fiber-sand mixtures based on particle flow code simulation

橡胶砂作为一种轻质填料在岩土工程中具有良好的应用前景,为揭示橡胶纤维-砂混合料强度特性、偏应力-轴向应变曲线及微观结构的变化规律,开展了橡胶纤维-砂不同配比的三轴剪切试验,基于颗粒流理论和PFC3D程序,对橡胶纤维-砂混合料的三轴剪切试验进行了数值模拟,并与室内试验结果进行了比较。结果表明:随着橡胶含量的增加,试样的应力-应变关系由应变软化型向应变硬化型过渡,试样剪切过程中体变形式逐渐由体胀型变为体缩型;同一围压下橡胶纤维含量高的试样变形模量小,表明橡胶材料的掺入有助于增强试样的压缩性能。

Rubber fiber-sand mixture has long been recognized as a light energy absorbing material with a good application prospect in engineering.To illustrate the variation laws of strength characteristics,curves of stress-strain and micromechanism of rubber fiber-sand mixtures,this study cinducted a triaxial shear test for different proportions of rubber fiber-sand mixture.The study performed the numerical simulation of triaxial tests on rubber fiber-sand mixtures using particle flow theory based on PFC3D,then compared the results of numerical experiments and laboratory tests.The results show that:the stress-strain relation is transited from strain softening to strain hardening,and the volumetric strain changes to shrinking from expansion gradually with the increase of the rubber fiber contents.Under the same confining pressure,the higher the rubber fiber contents are,the smaller the deformation modulus is.This indicates that the incorporation of rubber helps to enhance the compression performance of the sample.