This work extends the hydro-mechanical phase-field fracture model to non-isothermal conditions with micromechanics based poroelasticity, which degrades Biot’s coefficient not only with the phase-field variable (damage) but also with the energy decomposition scheme. Furthermore, we propose a new approach to update porosity solely determined by the strain change rather than damage evolution as in the existing models. As such, these poroelastic behaviors of Biot’s coefficient and the porosity dictate Biot’s modulus and the thermal expansion coefficient. For numerical implementation, we employ an isotropic diffusion method to stabilize the advection-dominated heat flux and adapt the fixed stress split method to account for the thermal stress. We verify our model against a series of analytical solutions such as Terzaghi’s consolidation, thermal consolidation, and the plane strain hydraulic fracture propagation, known as the KGD fracture. Finally, numerical experiments demonstrate the effectiveness of the stabilization method and intricate thermo-hydro-mechanical interactions during hydraulic fracturing with and without a pre-existing weak interface.

中文翻译：

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具有微机械应变能退化的热多孔弹性介质中的相场断裂模型


这项工作将流体力学相场断裂模型扩展到具有基于微观力学的孔隙弹性的非等温条件，这不仅会随着相场变量（损伤）而且会随着能量分解方案而降低毕奥系数。此外，我们提出了一种新的方法来更新孔隙率，该方法仅由应变变化决定，而不是像现有模型中的损伤演化那样。因此，比奥系数和孔隙率的这些孔隙弹性行为决定了比奥模量和热膨胀系数。对于数值实现，我们采用各向同性扩散方法来稳定平流主导的热通量，并采用固定应力分割方法来考虑热应力。我们根据一系列分析解决方案验证了我们的模型，例如 Terzaghi 固结、热固结和平面应变水力裂缝扩展（称为 KGD 裂缝）。最后，数值实验证明了稳定方法的有效性以及在有或没有预先存在的弱界面的水力压裂过程中复杂的热-水-机械相互作用。