岩石变形破坏过程耗散结构理论分析及损伤模型

将岩石视为系统,运用耗散结构理论分析能量在岩石系统形成有序耗散结构过程中的作用机制,揭示能量演化与强度变化、缺陷系统演化之间的关系和规律,在此基础上,以耗散能为参量建立描述缺陷系统演化过程的非线性动力学方程,推导耗散能演化方程,采用非线性最小二乘法对多种岩石的耗散能演化试验数据进行回归分析,验证耗散能演化方程的正确性。基于能量耗散和耗散能演化方程定义损伤变量表达式,从而得到能够反映岩石内部能量和力学作用机制的损伤演化方程。依据连续损伤理论建立考虑残余强度的岩石三维损伤本构模型,通过与多种岩石不同围压下的试验应力应变曲线进行对比,分析表明理论曲线与试验曲线吻合良好,所建损伤本构模型可以很好地描述复杂应力环境下岩石材料的变形与强度特性。

Dissipative Structure Theory Analysis of Rock Deformation and Failure Process and Damage Constitutive Model

Rock is considered a system, and the energy mechanism is analyzed during the rock system turning into an orderly dissipative structure; the relationship and law between energy evolution and strength variation along with defect system evolution are disclosed. The nonlinear dynamic equation based on dissipated energy that describes the defect system's evolution is established, which can deduce the evolution equation of dissipated energy. The nonlinear least square method is used to analyze the data of the dissipated energy from the compression tests of different kinds of rock under different confining pressures to verify the accuracy of the evolution equation of dissipated energy. The damage evolution law is established based on energy dissipation, which can reflect the energetic and mechanical mechanism inside the rock. A three-dimensional damage constitutive model that considers rock's residual strength is constructed under continuum damage theory. The achieved theoretical stress-strain curves by the damage model are comparatively analyzed with the curves from the tests of different kinds of rock; the results indicate that the proposed constitutive model can describe the strength and deformation behaviors of rock material under a complex stress environment.