中文摘要：

基于原状红黏土三轴不排水试验,得出桂林红黏土应力-应变关系,分析了原状红黏土结构损伤特性,确定损伤变量D,并对红黏土的损伤演化规律进行分析,验证其损伤本构关系。研究结果表明：桂林原状红黏土的应力-应变关系曲线表现出理想塑性的特点;不同围区条件下,轴向应变1.36%处可视作红黏土应变的门槛阈值,对应的应力作为应力门槛阈值;初始弹性模量和割线模量有关的变量D可作为损伤变量;损伤变量随主应力差的增大而增大,基本呈线性关系,损伤变量与轴向应变基本呈指数函数关系,表明红黏土损伤过程是不可逆的特点;本文提出的损伤本构方程能够较好地拟合红黏土的应力-应变曲线关系,反映不同围压条件下的红黏土结构性损伤变化规律。

英文摘要：

The triaxial undrained test of original red clay is conducted to investigate the stress-strain relationship of the red clay in Guilin.According to the characteristics of structural damage in red clay,damage variable D is determined.And the damage constitutive relations are verified by the damage evolution law of red clay.The results show that the characteristics of the ideal plastic are obviously exposed of the stress-strain relationship curves of the red clay in Guilin.Under the condition of different confining pressure,axial strain 1.36% can be regarded as the threshold of the red clay strain threshold,and the corresponding stress as stress threshold.The initial elastic modulus and secant modulus related variables can be used as damage variable D.Damage variable with the increases of principal stress difference and in the basic linear relationship.The relation of damage variable exponential function and the axial strain shows that the red clay damage process is irreversible.The damage constitutive equation presented in this paper can better fit stress-strain curve of red clay,and reflects red clay structural damage under different confining pressure conditions.