含水合物松散沉积物三轴试验及应变关系模型  

Triaxial shear test and strain analysis of unconsolidated hydrate-bearing sediments

作　　者：李彦龙[1,2] 刘昌岭[1,2] 刘乐乐[1,2] 黄萌[1,3] 孟庆国[1,2] 

机构地区：[1]青岛海洋地质研究所国土资源部天然气水合物重点实验室,山东青岛266071 [2]海洋科学与技术国家实验室海洋矿产资源评价与探测技术功能实验室,山东青岛266071 [3]中国海洋大学,山东青岛266100

出　　处：《天然气地球科学》2017年第3期383-390,共8页Natural Gas Geoscience

基　　金：国家自然科学基金面上项目(编号:41376078);国家自然科学基金青年科学基金项目(编号:41606078;11402131);中国科学院天然气水合物重点实验室基金(编号:Y607ke1001)联合资助

摘　　要：通过系列含水合物松散沉积物三轴试验,分析了沉积物应力—应变曲线基本变形规律,建立了用于描述轴向应变—体积应变、轴向应变—侧向应变关系的半经验模型,探讨了不同模型参数的敏感性及其物理意义。首次建立了三轴剪切破坏条件下含水合物松散沉积物发生应变软化、应变硬化2种破坏形式临界条件的判别方法。结果表明:建立的软化、硬化临界条件预测模型与试验结果吻合较好;在一定起始孔隙比条件下,含水合物沉积物破坏过程中的应变硬化、应变软化特性是由有效围压、水合物饱和度共同控制的;应变关系模型中不同的模型参数对曲线形态的影响机理不同,明确各模型参数的物理意义对于进一步认识应变关系曲线演化规律具有重要意义。Triaxial shear test is one of the effective ways to obtain strength parameters of hydrate-bearing sediment.Both volumetric strain and lateral strain were analyzed through triaxial shear test of unconsolidated hydrate-bearing sediments.A series of new semi-empirical equations were provided for axial-volumetric strain,axial-lateral strain and corresponding model parameters.Based on these analyses,critical failure mode prediction method was firstly provided.The results show that,in case of constant initial void ratio,failure mode of hydrate-bearing sediment is controlled by several parameters,such as effective confining pressure,hydrate saturation.The failure mode prediction method provided in this paper fits well with the experimental data.Furthermore,different model coefficients＇ effects on strain relationships are different,probing into the physical meaning of each coefficient is essential for further understanding of strain relationships.

关 键 词：含水合物沉积物 三轴试验 体积应变 轴向应变 侧向应变 

分 类 号：TE53[石油与天然气工程—油气田开发工程]