岩土力学2024，Vol.45Issue(7)：1987-1999,13.DOI:10.16285/j.rsm.2023.1641
赋存环境对含甲烷水合物沉积物力学特性的影响
The effect of occurrence environments on the mechanical behavior of methane hydrate-bearing sediments
摘要
Abstract
The shear strength and stiffness characteristics of methane hydrate sediments in seabed reservoirs are crucial for the safe and efficient exploration and exploitation of hydrates.To investigate the impact of changes in occurrence environments on the shear strength characteristics of muddy hydrate-bearing sediments,a series of drained shear tests have been conducted on methane hydrate-bearing muddy silt sediments under varying conditions of saturation(water-saturated and gas-saturated)and confining pressure based on the improved triaxial shear tester for hydrate-bearing sediments.The experimental results show that changes in the occurrence environment in sediments have significant effects on the shear strength and stiffness characteristics of hydrate-bearing muddy silt sediments.Compared to gas-saturated sediments,the shear strength of hydrate-bearing sediments with the same hydrate saturation greatly reduces under water-saturated condition,with a maximum reduction ratio of 52.0％.Although the effect of occurrence environmental changes on the internal friction angle of sediment is limited,the effect on the cohesion of sediment is significant.Compared to the results from gas-saturated sediments,the reduction ratio of the effective cohesion for the water-saturated hydrate-bearing sediments can reach 68.1％.Furthermore,the exponential equation is developed for describing the relation between the effective cohesion and hydrate saturation.Under water-saturated conditions,the deformation modulus of hydrate-bearing sediments decreases significantly,with a maximum reduction ratio of 72.7％for E50.Additionally,the deformation modulus increases linearly with hydrate saturation under water-saturated conditions.Lastly,based on the stress analysis of the skeleton of hydrate-bearing sediments under gas-saturated and water-saturated conditions,the evolution mechanism of the mechanical properties of hydrate-bearing sediments under these two different occurrence environments is preliminarily revealed.The observations can offer fundamental data and methods for recovering the occurrence mechanism of methane hydrate-bearing sediments and assessing the stability of the reservoir.关键词
甲烷水合物/泥质粉砂/水饱和/抗剪强度/变形模量Key words
methane hydrate/muddy silt/water-saturated/shear strength/deformation modulus分类
建筑与水利引用本文复制引用
冯帅,陈盼,周家作,韦昌富..赋存环境对含甲烷水合物沉积物力学特性的影响[J].岩土力学,2024,45(7):1987-1999,13.基金项目
国家自然科学基金项目(No.51939011) （No.51939011）
中国科学院青年创新促进会(No.2020326) （No.2020326）
中国科学院武汉岩土力学研究所创新探索项目.This work was supported by the National Natural Science Foundation of China(51939011),the Youth Innovation Promotion Association,CAS(2020326)and the Innovation and Exploration Project by Institute of Rock and Soil Mechanics,Chinese Academy of Sciences. （51939011）
