Q_2黄土流变特性及其统计损伤流变模型

Study on rheological properties and statistical damage rheological model for Q2 loess

摘要: 通过对西安地区不同湿度原状Q2黄土的单轴蠕变试验和三轴蠕变试验,得到了Q2黄土的单轴、三轴蠕变曲线和应力-应变等时曲线。试验曲线分析表明,Q2黄土具有明显的非线性流变特性。Q2黄土的粘弹性特性可采用五元件广义的Kelvin模型来描述,其线性粘塑性特性可用与一滑块并联的Maxwell模型来描述,而非线性粘塑性特性可通过损伤与塑性应变的耦合作用来反映。在考虑损伤门槛值的统计损伤及黄土粘弹塑性组合模型的基础上,应用应变等效原理,建立了考虑瞬时损伤的统计损伤流变模型,并通过拟牛顿法确定了相应的模型参数。该模型能够很好地模拟黄土流变非线性特征,该模型不仅参数较少,而且适用性较广。

Abstract: By means of indoor uniaxial and triaxial creep tests under different pressure of Q2 loess with different water contents in Xi’an areas,the uniaxial and triaxial creep curves and stress -strain isochronous curves are got. The results show that Q2 loess has nonlinearity rheological properties. On the basis of these,viscoelastic creep phase is simulated by the generalized Kelvin model,linear viscoplastic creep phase is simulated by the Maxwell model which is parallel connected by a slider,and nonli...