基于应变强度理论的岩石疲劳损伤本构模型

Fatigue Damage Constitutive Model of Rock and Correlation Analysis between Model Parameters and Fatigue Damage

针对岩石疲劳损伤的本构模型问题,通过分级加卸载试验。根据所得到应力应变曲线,分析其疲劳特征,根据应变强度理论,建立岩石疲劳损伤本构模型;使用Levenberg-Marquardt算法拟合得到本构的参数值,并对参数演化进行分析。研究表明:(1)随着试验进行,岩石残余应变逐渐累积,应力应变曲线和滞回环位置逐渐右移;(2)拟合参数与应力峰值有关,呈现有规律的变化;(3)根据应变强度理论建立的疲劳损伤本构模型能够较好地描述岩石在加卸载情况下的应力应变变化关系。

Aiming at the constitutive model of rock fatigue damage,the staged loading and unloading test is passed.According to the obtained stress-strain curve,analyze its fatigue characteristics,and the fatigue damage constitutive model of the rock is established according to the strain strength theory;the Levenberg-Marquardt algorithm is fitted to obtain the constitutive parameter values,and the parameter evolution is analyzed.The research shows that:(1)As the test progresses,the residual rock strain gradually accumulates,and the stress-strain curve and the hysteresis loop position gradually move to the right;(2)The fitting parameters are related to the peak stress and show regular changes;(3)According to the strain The fatigue damage constitutive model established by the strength theory can better describe the stress-strain relationship of the rock under loading and unloading conditions.