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采用长江科学院大型真三轴仪,对粗粒土进行了一系列不同中主应力系数条件下的真三轴试验和平面应变试验,研究了中主应力对粗粒土的应力变形的影响规律。试验结果表明,中主应力比b一定时,应力–应变关系曲线的斜率和峰值强度随着固结压力的增大而增加,在低围压条件下,体变关系曲线在加载过程中表现为先剪缩后剪胀的特性,而在高围压下,整个加载过程中表现剪缩的特性;固结压力一定时,随着b值的增大,应力在峰值后的软化现象愈加明显,体变全过程曲线表现出剪胀特征对应的固结压力越来越低,小主应变–大主应变关系曲线的斜率绝对值增大。研究成果可为进一步研究粗粒土的本构模型奠定基础。
The true triaxial test and plane strain test of coarse grained soil with different middle principal stress coefficients were carried out by the large true triaxial apparatus of Yangtze River Scientific Research Institute. The influence of middle principal stress on the stress and deformation of coarse grained soil was studied. The experimental results show that the slope and peak strength of the stress-strain curve increase with the increase of the consolidation pressure when the middle principal stress is higher than b. Under the low confining pressure conditions, the volume transformation curve shows as After shearing and shrinking, the stress-strain softening phenomenon after the peak value becomes more obvious with the increase of b value, The curve of body deformation process shows that the consolidation pressure corresponding to the dilatancy feature is getting lower and lower, and the absolute value of the slope of the small principal strain-principal strain curve increases. The research results can lay the foundation for the further study of the constitutive model of coarse grained soil.