中文摘要：

对含天然气水合物沉积物施加荷载后,其内部固体颗粒间将会发生错动、滑移及滚动,当荷载较小时,沉积物表现为弹性变形;随着荷载的增大,内部将出现塑性流动,水合物晶体重新定向,此时沉积物表现为塑性变形;随着荷载的进一步增大,最终导致沉积物发生破坏,这一过程可以看作是沉积物内部损伤产生和逐渐发展的过程。从复合材料的细观力学机制出发研究含水合物沉积物的材料特性,得到等效弹性常数与水合物含量之间的关系;同时基于损伤力学理论,推导出损伤变量的表达式,建立考虑损伤的含天然气水合物沉积物的本构模型。通过比较不同水合物含量下的计算结果与试验结果,结果表明,所建模型能较好地反映含天然气水合物沉积物的应力–应变关系,验证了模型的可行性。

英文摘要：

When a gas hydrate-bearing sediment is loaded, inter-particle processes such as dislocating, slipping and rolling will take place. Under small loading condition, the sediment deforms elastically; with the applied load increasing, plastic flow may occur, resulting in re-arrangements of hydrate crystal and the sediment deforms plastically; as the applied load further increasing, failure of the sediment will appear. This process represents the whole process of the damage producing and developing in the sediment. From the mesomechanics mechanism perspective of composite material, the material characteristics of gas hydrate-bearing sediments is investigated; and the relationship between hydrate saturation and equivalent elastic constants is established. Based on the principles of damage mechanics, the expression of damage variable is identified; and then a constitutive model for gas hydrate-bearing sediment considering damage is developed. The calculation results are compared with the experimental data for a gas hydrate-bearing sediment with different hydrate saturations. It is shown that the presented model can describe the stress-strain behavior of gas hydrate-bearing sediments quite well and the reasonability and feasibility of the model are verified.