摘要
对于峰后线性应变软化的地质体材料,剪切带内部的总剪切应变等于弹性剪切应变(由经典弹性理论描述)及由微结构效应而引起的局部塑性剪切应变(由非局部理论或梯度塑性理论描述)之和。若剪切应力—塑性剪切应变曲线的斜率的绝对值(称之为软化模量)小于剪切弹性模量的两倍,则在剪切带的任一剖面内存在两个总剪切应变不依赖于剪切应力的点,称之为常剪切应变点。在这两个点上,弹性剪切应变的降低和局部塑性剪切应变的增加处于平衡状态,总剪切速度达到它的最大值或最小值。在两个常剪切应变点之间,局部总速度随剪切应力率的降低而增加。剪切带内部的局部总速度分布是非线性的,这与通常采用的剪切带内部速度的线性分布假定(忽略微结构效应)不同。
For linear strain-softening geomaterials at post-peak, the total shear strain in the shear band （localized shear zone） is composed of the elastic strain （described by the classical elastic theory） and the local plastic shear strain due to the microstructural effect （described by the nonlocal theory or gradient-dependent plasticity）. If the shear softening modulus （the absolute value of the slope of the shear stressplastic shear strain curve） is less than two times of the shear elastic modulus, then two constant shear strain points exist in any section of a shear band. At the two points, the total shear strain is independent of the shear stress; the decrease of the elastic shear strain and the increase of the local plastic shear strain reach an equilibrium state; and the total shear velocity reaches its maximum or minimum value. With a decrease of the shear stress rate, the total shear velocity increases between the two constant shear strain points. In the shear band, the velocity distribution is nonlinear, as it is different from the traditional assumption of linear velocity distribution （neglecting the microstructural effect）.
出处
《防灾减灾工程学报》
CSCD
2009年第4期368-375,共8页
Journal of Disaster Prevention and Mitigation Engineering
基金
国家自然科学青年基金项目(50309004)资助
关键词
地质体材料
剪切带
常剪切应变点
速度分布
局部化
梯度塑性理论
geomaterials
shear band
constant shear dient-dependent plasticity strain point
velocity distribution
localization
gra
