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天然气水合物沉积物因其作为绿色新型能源且具有广阔的开发前景而备受全球瞩目。水合物在水合物沉积物(俗称能源土试样)中有不同的赋存型式,如孔隙填充型和胶结型等。针对孔隙填充型水合物的赋存形态,生成特定饱和度的能源土试样。开展了同一π平面上不同中主应力系数(b=0、0.25、0.50、0.75、1.00)的真三轴排水试验的三维离散元模拟,将微观参数接触组构及剪切滑移率的演化规律与材料的宏观力学响应相结合,分析了中主应力对孔隙填充型能源土的宏微观力学响应的影响。结果表明:强接触处组构张量的大、中、小主值随b的变化规律与大、中、小主应力及大、中、小主应变随b的变化规律表现出良好的相关性。三向应力状态下的破坏强度接近Lade-Duncan破坏准则。能源土试样剪切滑移率随着中主应力系数的增大而增大;当处于三轴拉伸状态时,试样的剪切滑移率最大。
Gas hydrate deposits have drawn global attention because of their potential as green new energy sources and their promising development prospects. Hydrates have different patterns of occurrence in hydrate deposits (commonly known as energy soil samples), such as pore-filled and cemented types. Aiming at the occurrence mode of pore-filling hydrate, energy soil sample with specific saturation is generated. Three-dimensional discrete element simulation of true triaxial drainage tests with different mid-main stress coefficients (b = 0,0.25,0.50,0.75,1.00) on the same π-plane was carried out. The evolution of micro-parameter contact structure and shear slip ratio Law and the macroscopic mechanical response of the material, the influence of middle principal stress on the macro-micromechanical response of the pore-filled energy soil is analyzed. The results show that the major, minor and major principal values of the large, medium and small principal tensions of strong contact points vary with the variation of b, the principal stresses of large, medium and small, and the principal, intermediate, . The failure strength under three-stress state approaches the Lade-Duncan failure criterion. The shear slip rate of energy soil samples increases with the increase of the main stress coefficient, and the shear slip rate of the sample increases with the triaxial tension.