正冻多孔介质耦合模型研究

 通过分析多孔介质孔隙水的相变过程，研究孔隙冰与孔隙水含量随温度改变的变化规律，建立描述冷冻条件下孔隙冰与孔隙水饱和度的数学关系式。通过引入低温多孔介质有效孔隙压力概念，建立基于多孔连续介质力学理论的低温多孔介质孔隙压力变化的耦合模型，提出低温冻结情况下饱和非饱和多孔介质的体积热膨胀系数表达式。应用现有的试验成果论证此研究模型的正确性。研究成果表明建议的模型能够正确地模拟正冻孔隙介质的有效孔隙压力和骨架应力，并能反映冻胀融缩的变形特点，为科学研究低温多孔介质的应力与变形特点提供合理可靠的方法。

STUDY OF COUPLING MODEL OF FREEZING POROUS MEDIA

Based on analysis of the water phase change process in porous media，the volumetric ratio of pore water to pore ice versus temperature is studied. A mathematic relation to describe saturated degree of pore water and pore ice undergoing freezing condition is suggested. Through the introduction of effective pore pressure concept，a coupling model based on theory of porous media is studied to simulate the variation of effective pore pressure under low temperature situation. Formulae to be able to calculate the thermal volumetric dilation coefficient of saturated and unsaturated porous media are employed to describe swelling and shrinkage characteristics of freezing porous media. The comparison results between experimental data and simulated solution validate the correctness of the proposal model in this research. It also indicates that this model could simulate the reasonable solution of effective pore pressure and skeleton stress and describe the swelling and shrinkage deformation feature. Therefore the suggested coupling model is a reasonable and effective approach for the study of the deformation and stress of freezing porous media.