粘性土剪切带与屈服应力的探讨

An exploration of shear band of cohesive soils and yield stress

利用全自动三轴仪,对南京地区典型的粉土、粉质粘土试样进行了固结不排水剪试验,研究具有剪切带性状试样的孔隙水压力随偏应力的变化关系,分析屈服应力、孔隙水压力和土体分叉之间的关系.试验结果表明,孔隙水压力的峰值可以表征土体局部开始屈服,并出现应变局部化的状态.围压的增大会延迟土体分叉,而干密度较大时易出现剪切带.可用土体初始分叉点来确定土体的强度参数.

The undrained shear tests of Nanjing silty and silty clay were conducted by the KTG to investigate relationships between pore water pressure and deviator of specimens with shear band, and to analyze yield stress and pore water pressure and soil bifurcation. The experimental analysis shows that water pressure peak can illuminate the state when some districts in soil begin to yield and deformation localization occurs. The soil bifurcation will be delayed as the confining pressure increases. But shear band is apt to come in the specimen with high dry density. The strength parameters can be determined by onset of soil bifurcation.