The presence of fine particles has a significant impact on the mechanical behavior of hydrate-bearing sediments. In this study, a series of isotropic compression and triaxial tests were conducted using a customized testing system for the hydrate-bearing sediment. Carbon dioxide hydrate was formed in the host sediments, which were mixtures of sand and silty-sized quartzitic or illite fine particles. The isotropic and triaxial compression tests offered valuable datasets of the compression and the swelling indices, yielding stress, strength, stiffness, and dilatancy for hydrate-bearing sediments. The results highlighted that the addition of illite particles enhances compressibility but restricts stiffness and dilatancy. The strength is highly increased by hydrate saturation and less dependent on the mineralogy of fine particles. The cohesion is significantly enhanced by the hydrate saturation due to cementation. With the increasing hydrate saturation, the angle of internal friction increases slightly at lower hydrate saturation but it decreases slightly at higher hydrate saturation. The experimental results and mechanism analysis can be used to assess the stability of the hydrate reservoir under methane-carbon dioxide replacement and provide a reference to estimate the mechanical properties of the methane hydrate reservoir.

细颗粒的存在对含水合物沉积物的力学行为具有重大影响。在这项研究中，使用针对水合物的沉积物的定制测试系统进行了一系列各向同性的压缩和三轴测试。主体沉积物中形成了二氧化碳水合物，这些沉积物是沙子和粉质石英岩或伊利石细颗粒的混合物。各向同性和三轴压缩试验提供了有价值的数据集，包括含水率沉积物的压缩和溶胀指数，屈服应力，强度，刚度和膨胀率。结果突出表明，伊利石颗粒的添加增强了可压缩性，但限制了刚度和膨胀性。水合物的饱和度使强度大大提高，而对细颗粒的矿物学的依赖性则较小。由于胶结作用，水合物饱和会大大增强内聚力。随着水合物饱和度的增加，内摩擦角在较低水合物饱和度时略有增加，但在较高水合物饱和度时略有减小。实验结果和机理分析可用于评估甲烷-二氧化碳置换条件下水合物储层的稳定性，为估算甲烷水合物储层的力学性能提供参考。