摘要
循环荷载下盐岩流变模型,是岩石力学的重要内容之一。利用Poyhting-Thomson模型,根据岩样真实循环加载疲劳过程,推导出初始匀速加载段和正弦循环加载段的应变随时间变化的本构方程。对盐岩进行了循环加载疲劳试验,由于疲劳损伤的原因,平均应变值随时间延长等速增加。据此,对理论本构方程进行了修正,用时间的幂函数来描述应变增量,得到了修正的Poyhting-Thomson疲劳流变本构方程。匀速加载阶段理论模型能较好模拟试验曲线。用修正的流变本构模型对循环加载疲劳阶段的应变曲线的上限线、下限线和中间线进行拟合分析,得到了相应的拟合参数。取参数的平均值,用修正模型对试验疲劳曲线进行了模拟,模拟曲线与试验曲线比较接近,几乎可以代替试验。通过试验和数学验证表明,Poyhting-Thomson模型及其修正的模型,来描述循环载荷作用下盐岩的疲劳应变发展是可行的,能较好的刻画应变随时间变化的规律。
The rheological model of rock salt under cyclic loading is one of important contents of rock mechanics.Here,according to the actual cyclic loading fatigue process of rock salt samples,rock salt's strain versus time constitutive equation within initial uniform velocity loading stage and sinusoidal cyclic loading one was deduced based on PoyhtingThomson model.The cyclic loading fatigue tests of rock salt were conducted.Due to fatigue damage,the average strain increases at equal speed with increase in time.Accordingly,the theoretical constitutive equation was modified,and the power function of time was used to describe the strain increment to obtain the modified Poyhting-Thomson fatigue rheological constitutive equation.In uniform velocity loading stage,the theoretical model was able to simulate the test curve well.The modified rheological constitutive model was used to fit the upper limit line,lower limit one,and middle one of rock salt's fatigue strain curve in cyclic loading stage to get corresponding fitting parameters.Then taking the average values of fitting parameters,the modified model was used to simulate the fatigue test curve,the simulated curve agreed well with the test one and it could almost replace the test one.Test and simulation showed that Poyhting-Thomson model and its modified model are feasible to describe rock salt's fatigue strain development under cyclic loading,they can better depict the law of rock salt's strain versus time.
作者
许宏发
齐亮亮
刘斌
柏准
XU Hongfa;QI Liangliang;LIU Bin;BAI Zhun(State Key Lab of Disaster Prevention and Mitigation of Explosion and Impact, Army Engineering University of PLA, Nanjing 210007, China)
出处
《振动与冲击》
EI
CSCD
北大核心
2018年第13期203-209,共7页
Journal of Vibration and Shock
基金
江苏省自然科学基金项目资助(BK20141067)