重塑粉质黏土的剪切蠕变特性及本构模型研究

通过室内三轴试验,对重塑粉质黏土的剪切蠕变特性进行研究,分析了粉质黏土在不同偏应力水平下和不同偏应力分级方式下的蠕变变形特性。试验表明,粉质黏土的偏应变蠕变变形与对数时间关系具有明显的非线性;在同样的剪切应力水平下,不同的加载分级方式对试样的最终偏应变量有明显的影响,加载分级越多,最终的偏应变量越小。基于试验数据,建立了适合描述重塑粉质黏土蠕变特性的双曲线模型,并对模型参数的物理意义和取值方法进行了讨论。分析表明,模型参数的取值与应力水平及试样的初始孔隙比有关;结合试验结果,给出了粉质黏土剪切蠕变双曲线模型参数取值建议。

Research on Creep Characteristics and Creep Model of Reconstituted Silty Clay

Triaxial tests were carried out under different shear stress level and with different loading stages to investigate the creep behavior of reconstituted silty clay. The results show that the deviatoric strain-lgt curves of the silty clay under different stress levels and with different loading stages are nonlinear, and the higher the shear stress level is, the more deviatoric creep develops. It is also found that the preloading steps have a pronounced effect on the final deviatoric strain development with that the more stages of the loading, the less deviatoric strain evolves. Based on the tests, a hyperbolic model is proposed to describe the creep behavior of the reconstituted silty clay. Two model parameters, both with sound physical meanings, were analyzed according to the test data. It was found that the model parameters are related to the stress level and the initial void ratio of the soil sample. The values of the model parameters were then suggested for silty clay under triaxial shear.