含CO_2水合物沉积物力学特性研究

Mechanical Properties of CO_2 Hydrate Sediment

参照我国南海神狐海域含天然气水合物富集区沉积物的特点,配制近似粒径的泥质粉细砂作为水合物的赋存骨架,利用含天然气水合物多功能设备制备含CO_2水合物泥质粉细砂,进行三轴剪切试验,研究水合物对赋存介质的强度与变形特性的影响。试验结果表明:在净围压相同的情况下,随着水合物饱和度增大,含CO_2水合物沉积物的强度和刚度都增大并出现剪胀现象,土样黏聚力也有明显上升,但对内摩擦角影响不大。在饱和度相同的情况下,随着围压的增大,土样的强度逐渐增强,应变硬化趋势明显,且剪胀趋势减弱。

Referring to the characteristics of sediments in the natural gas hydrate-rich area of the Shenhu sea area in the South China Sea,the Silty fine sand specimens with approximate particle size was prepared as the hydrated skeleton,and the CO2 hydrate samples was prepared by using the natural gas hydrate triaxial test system.The CO2-hydrate soil samples were conducted triaxial shear test to study the effects of hydrate on the strength and deformation characteristics for the medium.The experimental results show that with the same net confining pressure,as the hydrate saturation increases,the strength and stiffness of CO2 hydrate deposits increase and dilatancy occurs,and the cohesion of soil samples also increases significantly.However,it has little effect on the internal friction angle.In the case of the same saturation,as the confining pressure increases,the strength of the soil sample gradually increases,and the strain hardening clearly trend with dilatancy tend to decrease.