变形条件下岩石裂隙的气-液两相渗透特性及其耦合效应研究

The variation of gas-liquid two phase permeability of rock fracture under deformation and its coupling effect is a key issue that needs to be addressed urgently in the areas of rock engineering, and is also a fundamental subject in the field of rock mechanics. By laboratory tests, theoretical analysis and numerical simulation, the project intends to give an insight into the microcosmic surface property of rock fracture and its influence on the gas-liquid two phase permeability. The capillary pressure model and two phase relative permeability model will be presented with the consideration of the microcosmic surface property of rock fracture. The variation model for gas-liquid two phase permeability of rock fracture will also be presented to account for the effects of deformation. Then, a mathematical model and a numerical method for coupled deformation-two phase flow processes for rock fracture will be presented with the consideration of the variation of two phase structure influence on stress state and deformation properties. Finally, the coupled deformation-two phase flow processes under the condition of rainstorm will be simulated to capture the instability of fractured rock bank slopes, and the dynamic two phase flow processes of for water sealed underground petroleum storage caverns and nuclear waste repository with the consideration of excavation disturbances will be simulated. This study will provide an important theoretical contribution to the issue of gas-liquid two phase flow behaviors and its coupling effects under deformation for rock fracture, and also provide important actual application value for seepage control design and optimization of rain-induced landslide, water sealed underground petroleum storage caverns and underground nuclear waste repository engineering in China.

变形条件下岩石裂隙气-液两相渗透特性及其耦合效应是众多岩体工程中迫切需要解决的关键问题，也是岩石力学领域的重要基础性研究课题。本项目采用试验、理论分析和数值模拟相结合的方法，研究裂隙的微观形貌特征对气-液两相渗透特性的影响，建立基于微观形貌特征的岩石裂隙毛细压力曲线模型和两相相对渗透系数模型，研究变形条件下岩石裂隙的气-液两相渗透机理，建立变形条件下气-液两相渗透特性模型以及裂隙变形与气-液两相渗流耦合理论模型与数值模拟方法，模拟降雨条件下裂隙岩质边坡的水-汽两相渗流、变形与滑坡过程，模拟水封油气洞库两相渗流场的动态变化过程以及开挖条件下地下核废料处置库围岩中的水-汽迁移过程。研究成果对深化变形条件下岩石裂隙气-液两相渗透特性演化机制及其耦合效应的研究具有重要的理论意义，对于解决我国降雨诱发岩质边坡滑坡、高放废物地质处置、水封油气洞库等工程中的渗控设计与优化问题具有重大的应用价值。

变形条件下岩石裂隙气-液两相渗透特性及其耦合效应是众多岩体工程中迫切需要解决的关键问题，也是岩石力学领域的重要基础性研究课题。本项目采用试验、理论分析和数值模拟相结合的方法，重点研究了裂隙的微观形貌特征对气-液两相渗透特性的影响，建立了基于微观形貌特征的岩石裂隙毛细压力曲线模型和两相相对渗透系数模型，研究了变形条件下岩石裂隙的气-液两相渗透机理，建立了变形条件下气-液两相渗透特性模型以及裂隙变形与气-液两相渗流耦合理论模型。并针对降雨诱发滑坡、水封石油洞库、CO2地质封存工程中的变形、单相/多相渗流问题展开了数值模拟和工程应用分析，经过三年努力，取得的主要创新性研究成果如下：（1）首次揭示了能考虑复杂变形（尤其是剪切变形）情况下裂隙形貌特征变化规律，并基于此提出了基于形貌特征演化的岩石裂隙饱和/非饱和/气-液两相渗透模型（包括毛细压力曲线模型及相对渗透系数模型）；（2）采用数学模型描述了水封石油洞库油品蒸汽压力对洞库围岩渗流场的影响，运用有限元数值方法首次揭示了油品蒸汽入侵洞顶围岩的情况，并据此提出了基于三维数值模拟分析的水封准则；（3）分析了我国首个CO2地质封存示范工程-神华鄂尔多斯CO2处置库深部岩体裂隙产生、发展的原因及岩体渗透特性演化的内在原因。研究成果对深化变形条件下岩石裂隙气-液两相渗透特性演化机制及其耦合效应的研究具有重要的理论意义和应用价值。研究期间发表论文5篇，其中被SCI/EI检索3篇，另外在投相关论文3篇，申请发明专利1项，培养硕士研究生5名。