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天然气水合物(以下简称水合物)的不当开发可能会带来一系列的地质灾害和环境问题,因此,开展含天然气水合物地层开采过程中的安全稳定性评估显得尤为重要,而建立能有效描述含水合物沉积物的力学行为的本构模型是安全稳定性分析的核心前提。在分析含CO_2水合物砂土的三轴力学特性的基础上,把含水合物沉积物视为水合物和土颗粒骨架组成的复合胶结性材料,参考胶结土体的建模思路,引入附加内变量描述水合物对土体的胶结影响,建立了含水合物砂土的屈服函数和非关联流动法则,建立了含水合物砂土的本构模型。通过模型验证及分析,模型能较好地模拟不同围压下和不同水合物含量下含水合物砂土的应力应变曲线,反映含水合物砂土的力学特性。
The improper development of natural gas hydrates (hereinafter referred to as hydrates) may bring about a series of geological disasters and environmental problems. Therefore, it is particularly important to carry out safety and stability assessment during the development of gas hydrate formations, and establishment can be effectively described. The constitutive model of the mechanical behavior of the hydrate deposits is the core premise of the safety and stability analysis. Based on the analysis of triaxial mechanical properties of CO 2 -containing hydrated sands, the hydrate deposits are regarded as composite cementing materials consisting of hydrates and soil particles, referring to the modelling concept of cemented soils and introducing additional The variable describes the cementation effect of hydrate on soil, establishes the yield function and non-associated flow rule of hydrated sand, and establishes the constitutive model of hydrated sand. Through model validation and analysis, the model can simulate the stress-strain curves of hydrated sand under different confining pressures and different hydrate content, reflecting the mechanical properties of hydrated sand.