岩石循环冲击损伤演化模型及静载荷对损伤累积的影响  

EVOLUTION MODEL FOR DAMAGE ACCUMULATION OF ROCK UNDER CYCLIC IMPACT LOADINGS AND EFFECT OF STATIC LOADS ON DAMAGE EVOLUTION

作　　者：金解放[1] 李夕兵[2] 邱灿[1] 陶伟[1] 周学进[1] 

机构地区：[1]江西理工大学建筑与测绘工程学院,江西赣州341000 [2]中南大学资源与安全工程学院,湖南长沙410083

出　　处：《岩石力学与工程学报》2014年第8期1662-1671,共10页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助项目(51104068);江西省教育厅科技项目(GJJ13406);江西省科技厅科技支撑计划(20132BBG70106)

摘　　要：为系统、深入探索静载荷与循环冲击组合作用下岩石疲劳力学性能及其影响因素,研究建立岩石损伤累积演化模型,并探索静载荷对岩石损伤累积的影响。基于静载荷与循环冲击组合作用下岩石损伤累积演化具有"快速上升→平缓发展→急速上升"的趋势,并与S型曲线进行对比,将Logistic函数进行逆变换,建立静载荷与循环冲击作用下岩石损伤累积演化的数学模型。将模型中3个参数值固定,变化另一参数值的大小,分析所得损伤曲线簇的变化规律,确定损伤演化模型中参数的物理意义。基于最小二乘逼近理论,建立损伤模型拟合的目标函数,通过在Matlab中编写拟合程序,得到损伤模型的拟合方法。最后用试验数据验证模型的正确性。利用损伤模型拟合不同静载荷下岩石循环冲击的损伤试验结果,分析模型中参数与静载荷间的关系,研究静载荷的大小对岩石损伤累积演化的影响。结果表明,该损伤模型理论依据充分,关系式简单,参数物理意义明确,能表征静载荷与循环冲击组合作用下岩石损伤累积演化的初始阶段、低速阶段和加速阶段,能体现出轴压和围压对岩石损伤累积演化的影响。围压和轴压的大小影响岩石疲劳损伤的演化趋势,围压越大,轴压大小的变化对参数α,β和η的影响越小;无论轴压大小如何变化,围压大小的变化始终影响岩石损伤累积演化趋势。In order to explore the fatigue properties and its influence factors,an evolution model of damage accumulation was established and the effect of static loading on the damage accumulation of rock under cyclic impaction was studied. Compared with the S-shaped growth curve,a model of the damage evolution of rock having a trend of rapid rising,steady development and sharp rising subjected to the coupled static-cyclic impact loadings was established using the inverse transformation of logistic function. The physical meanings of the parameters in the damage accumulation model were determined by analyzing the variation of the curves with three parameters fixed and one varying. The objective function for fitting the damage model was established based on the approximation theory of the least squares. After programmed with Matlab,the data fitting of the damage＆amp;nbsp;accumulation model was calculated and the damage accumulation model was proved to be correct by the test data. The evolution model of damage accumulation was used to fit the experimental data of rock damage upon cyclic impaction under different static loadings. The effect of static loading on damage accumulation was studied through analyzing the relation between the fitting parameters and the static loadings. The axial pressure and the confining pressure have great effect on the trend of dynamic fatigue damage of rock. The change of axial pressure has smaller influence on the parametersα,βandη with the confining pressure increasing. The change of confining pressure always influences evolution the trend of dynamic damage accumulation no matter how much the value of the axial compression is.

关 键 词：岩石力学 循环冲击 静载荷 损伤累积 演化模型 

分 类 号：TU45[建筑科学—岩土工程]