砂土塑性应变增量方向影响因素分析及原因探讨

Analysis on factors affecting the direction of plastic strain increment in sand

以福建标准砂为试验材料,主要研究了不同应力状态下不同应力增量方向对砂土材料塑性应变增量方向的影响及其原因。试验结果表明,随着应力增量方向角增大,塑性应变增量方向角逆时针旋转,但两个角度不重合;应力状态越高,砂土剪胀所对应的应力增量方向角范围越大,塑性应变增量方向角范围越小,并得到砂土处于临界状态时仍有塑性体积应变产生的结论。分别从平均应力增量、广义剪应力增量以及应力状态三个角度阐述了砂土的塑性流动机理,为砂土塑性应变增量方向的相关研究提供理论参考及数值支撑。

Taking the standard sand of Fujian as the test material,the influence of different stress increment directions on the direction of plastic strain increment of sand materials were studied under different stress states and its reasons. The test results show that the plastic strain increment angle rotates counterclockwise with the increase of stress increment direction angle,but the two angles do not coincide;the higher the stress state,the larger the stress increment direction angle range corresponding to sand dilatation,the smaller the plastic strain increment direction angle range,and the plastic volumetric strain still increases in critical state. The plastic flow mechanism of sand was expounded from three aspects of average stress increment,generalized shear stress increment and stress state,which provides theoretical reference and numerical support for the related research of sand plastic strain increment direction.