基于改进Harris函数的砂岩损伤本构模型研究

Constitutive Model of Sandstone Damage Based on Improved Harris Function

岩石损伤量在岩石损伤的过程中是个动态变化量,通过改进Harris函数,建立了在三维应力作用下岩石损伤本构模型,并通过砂岩的三轴试验确定了模型参数,定性分析了围压、临界损伤值、峰值应变三者间的关系。研究结果表明:1基于改进的Harris函数所建立的砂岩损伤本构模型曲线与实测曲线拟合较好,有良好的适用性;2同一种岩石在不同围压下,临界损伤值不是固定值,它从侧面反映出岩石自身的力学性能与岩石所处的三维应力状态有关;3围压增大,临界损伤值也相应地增大,证明围压对岩石的破坏有抑制作用。分析结果对研究三维应力状态下岩石的损伤破坏机理有一定借鉴意义。

The damage value of rock changes dynamically in the process of rock damage. By improving the Harris function,a damage constitutive model of rock under three-dimensional stress is established,and the parameters of the model are determined through triaxial test on sandstone. The relationships among confining pressure,critical damage value,and peak strain are analyzed qualitatively. Research results show that： 1） the model curve of sandstone＇s damage constitutive model based on improved Harris function is well fitted with the measured curve,and has good applicability; 2） the critical damage value is not a fixed value for the same kind of rock under different confining pressures,indicating that the mechanical properties of rock are related to its three dimensional stress state; 3）the critical damage value increases correspondingly when confining pressure increases,which proves that confining pressure has a restraining effect on rock damage. The analysis results have a certain reference significance for the study of damage mechanism of rock under three-dimensional stress condition.