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天然气水合物的分解开采过程将会劣化深海能源土的力学性能,从而引发一系列岩土工程问题。因此,要实现天然气水合物的安全开采,需要对能源土的强度和变形特性开展研究。结合深海能源土微观胶结模型,通过平面应变双轴试验的离散元模拟,研究了深海能源土剪切带形成机理以及剪切带内外的宏微观变量特征。结果表明:水合物胶结提升了深海能源土的强度,且使其呈现出明显的应变软化特性;剪切带在峰值应力后开始产生,伴随着胶结的大量破坏以及各宏微观变量的局部化;剪切带内外各宏微观变量差异明显,随着轴向应变的增加,土体微观结构也随之发生变化。
Natural gas hydrate decomposition mining process will degrade the mechanical properties of deep-sea energy soils, causing a series of geotechnical problems. Therefore, in order to realize the safe exploitation of natural gas hydrate, the strength and deformation characteristics of energy source soil need to be studied. Combined with deep-sea soil microcosmic cementation model, the formation mechanism of deep-sea energy soil shear zone and the characteristics of macro-micro variables inside and outside the shear zone are studied by discrete element simulation of plane-strain biaxial test. The results show that the hydrate cementation enhances the strength of deep-sea energy soils and makes it show obvious strain softening characteristics. The shear band begins to emerge after peak stress with a large amount of cementing failure and localization of the macroscopic and micro-variables. The macroscopic and microscopic variables within and outside the shear zone are obviously different. As the axial strain increases, the microstructure of the soil changes accordingly.