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为了探索煤质页岩的压缩变形及损伤破坏特性,利用MTS岩石材料力学试验机,得到了煤质页岩的单轴和三轴压缩试验曲线,研究了单轴三轴压缩全过程中页岩损伤软化特征的异同;在此基础上,研究分析了页岩压缩过程中外力功、能量耗散以及能量释放机理,结合页岩特性和岩石强度破坏理论,建立了基于能量原理的页岩损伤演化本构方程:①单轴应力状态下,页岩损伤全过程可用能量原理损伤本构方程模拟;②三轴应力状态下,当轴向应力小于围压时,页岩本构关系可近似用线性方程模拟;当轴向应力大于围压时,应用基于能量原理损伤本构方程进行模拟。模型与试验结果对比分析显示,所建的模型力学参数简单,物理参数意义明确,能充分描述页岩单轴应变软化及三轴应变硬化阶段变形特征。
In order to explore the compressive deformation and damage characteristics of coal-based shale, the uniaxial and triaxial compression test curves of coal-bearing shale were obtained by MTS rock mechanics testing machine. The shale On the basis of this, the mechanism of external force work, energy dissipation and energy release during shale compression was studied. Based on the shale characteristics and the rock failure theory, the damage evolution of shale based on energy principle was established Constitutive equation: (1) In the uniaxial stress state, the energy principle can damage the constitutive equations in the whole process of shale damage; (2) Under the condition of triaxial stress, the constitutive relation of shale can be approximated linearly Equation simulation; when the axial stress is larger than confining pressure, the damage constitutive equation based on energy principle is simulated. The comparative analysis between the model and experimental results shows that the model has simple mechanical parameters and clear physical parameters, which can fully describe the deformation characteristics of shale uniaxial strain softening and triaxial strain hardening stage.