A fully coupled thermo-poro-mechanical finite element analysis to predict the thermal pressurization and thermally induced pore fluid flow in soil media
A fully coupled thermo-poro-mechanical finite element analysis to predict the thermal pressurization and thermally induced pore fluid flow in soil media
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DOI：
10.1016/j.compgeo.2019.103250
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发表时间：
2020
影响因子：
5.3
通讯作者：
Mohammadreza Mir Tamizdoust;Omid Ghasemi-Fare
中科院分区：
文献类型：
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作者：
Mohammadreza Mir Tamizdoust;Omid Ghasemi-Fare
饱和多孔介质中的温度梯度和热传递可能影响孔隙流体压力和/或孔隙流体流量，这取决于介质和饱和流体的热、机械和水力性质。因此，人们发展了几种热-水-力学（THM）模型来从理论上分析土壤介质的热行为。本文采用热-孔-力学耦合模型研究了瞬态和准稳态条件下可变形多孔介质中的传热传质问题。考虑了多孔介质不同性质的影响和重要性，模拟了两种不同情况下的不同情景。结果证实，为了准确地预测热增压和总应力的变化，必须仔细考虑土壤和饱和流体的性质的温度依赖性。结果发现，即使是轻微的扰动孔隙度的变化和温度依赖性的流体的热膨胀系数可以极大地影响热加压的孔隙流体在非常低的渗透性土壤（如粘土），而孔隙流体密度的变化支配热诱导的孔隙流体流动在高渗透性土壤（如砂和粉砂）。此外，热对流和热诱导孔隙流体流动的可行性进行了讨论，在不同的温度和渗透率值的参数研究。结果表明，Boussinesq近似是处理准稳态条件下热致孔隙流体流动的关键假设。
Temperature gradient and heat transfer in saturated porous media may affect pore fluid pressure and/or pore fluid flow depending on thermal, mechanical, and hydraulic properties of the media and the saturating fluid. Therefore, several Thermo-hydro-mechanical (THM) models have been developed to theoretically analyze the thermal behavior of soil media. In this study a coupled thermo-poro-mechanical model is adopted to investigate the heat and mass transfer in deformable porous media in a transient and quasi-steady state conditions. The Effects and importance of different properties of porous media are carefully taken into account to simulate two different cases with different scenarios. The results confirm that in order to accurately predict the thermal pressurization and changes in total stress, temperature dependency of properties of the soil and saturating fluid must be considered carefully. It is found that even a slight perturbation in porosity variation and temperature dependency of the thermal expansion coefficient of the fluid can greatly influence the thermal pressurization of pore fluid in very low permeable soils (e.g. clays), while variations of pore fluid density governs thermally-induced pore fluid flow in high permeable soils (e.g. sands and silty sands). Moreover, the feasibility of heat convection and heat-induced pore fluid flow is discussed in a parametric study with different temperature and permeability values. The results demonstrate that the Boussinesq approximation is a key assumption when dealing with heat-induced pore fluid flow in quasi-steady state condition.