考虑冻融效应的岩石损伤统计强度准则研究

Study of damage statistical strength criterion of rock considering the effect of freezing and thawing

从岩石微元强度服从Weibull分布的角度出发,运用损伤力学理论,考虑冻融与荷载的耦合作用,建立了岩石总损伤模型,并开展红砂岩冻融循环力学特性试验,验证了模型的合理性.在此基础上,根据岩石应力应变曲线的极值特性,利用多元函数全微分的方法建立了考虑冻融效应的岩石强度准则.研究表明:模型参数与岩石变形破坏参量的理论关系,可反映冻融损伤的内在机制与所选物理量的一般变化规律,增强了准则的适应性;所建强度准则的理论曲线与试验曲线吻合度较高,并能够反映岩石强度莫尔包络线的曲线特征,且考虑了岩石的损伤特性;与其它强度准则相比,该强度准则能反映不同冻融次数下各极限状态的应力应变与岩石参数之间的关系,可为寒区岩土工程结构稳定性评价提供一定的参考.

Based on the strength of rock micro-unit obeys the Weibull random distribution,a damage constitutive model was built with considering coupling action between freeze-thaw and load,and the test of the mechanical properties of the red sandstone in freeze-thaw cycles was used to verify the rationality of the model.Then,according to the concept of the characteristicsof the stress strain curve,the method of full differential function was employed to establish the damage statistical strength criterion of rock,which considered the effect of freezing and thawing.The results show that the theoretical relationship between the model parameters and the rock deformation and failure parameters can reflect the change of the internal mechanism and the physical quantity,and the theoretical curve of the strength criterion is more approaching to the experimental result,which greatly enhance the adaptability of the criterion.Besides,the strength criterion,which consider the damage characteristics of rock,can reflect the characteristics of the rock strength Mohr envelope curve.Compared with existing researches,the strength criterion advised in this paper has better ability to describe the relationship between stress and strain with strength of rock in different freezing and thawing cycles,and which is helpful to provide reference for the evaluation of structural stability in geotechnical engineering.