黄土三轴剪切蠕变特性研究

Triaxial shear creep characteristics of loess

以陕西省杨凌示范区某黄土边坡黄土试样为研究对象,进行了一系列室内三轴剪切蠕变试验,对三轴应力条件下黄土的剪切蠕变特性进行了研究,分析了时间、偏应力水平对应变速率的影响。建立了适合杨凌地区黄土的经验蠕变模型,通过与Burgers模型的比较发现,该经验蠕变模型具有精度高、参数少且获取途径简便的优点,能够很好地描述杨凌地区黄土的应力–应变–时间关系。另外,由试验资料发现三轴应力条件下黏滞系数与偏应力、时间具有密切的关系,并推导出黏滞系数与偏应力、时间的经验公式,并对该经验关系进行了验证。

By taking the samples from a loess slope of Yangling District in Shaanxi Province as the study object,a series of triaxial shear creep tests are carried out to analyze the shear creep characteristics of loess under complex stress condition.Based on the experimental data,the impact of time and deviatoric stress on strain rate is analyzed.An empirical creep model suitable for Yangling District is proposed.It is shown that the model can describe the stress-strain-time relationship with higher accuracy,fewer parameters and easier method of obtaining parameters by the comparison between empirical creep model and experimental data.Besides,under triaxial stress condition,the viscous coefficient is closely related to the deviatoric stress and time.An empirical formula is suggested to simulate the relationship among the viscous coefficient,the deviatoric stress and the time.The verification results prove its applicability and accuracy.