超深地层盐岩单轴压缩损伤演化过程分析

Analysis of damage evolution of rock salt under uniaxial compression in ultra-deep formation

以潜江储气库超深地层盐岩为具体研究对象,利用MTS815岩石力学测试系统,开展单轴压缩试验。试验发现:盐岩单轴压缩过程未表现出明显的压密阶段,整个应力-应变曲线可分为较短的初始无损弹性阶段、损伤快速积累的塑性平台阶段、损伤继续发展的峰后阶段等。基于盐岩单轴压缩变形和破坏过程,建立损伤演化数学模型,该模型与试验曲线吻合度较高,能够较好地反应潜江深部盐岩的应力-应变过程及损伤演化过程。针对超深地层盐岩在单轴压缩下的劈裂破坏,给出力学解释。研究成果对地下盐穴储气库的建设具有一定的指导意义。

To address the damage evolution of rock salt in Qianjiang,uniaxial compression tests were carried out by using the MTS815 rock mechanics test system.The specimens were collected from the target formation.The results showed that there was no obvious compaction stage in the uniaxial compression of rock salt.The stress-strain curve could be divided into three stages:initial non-damage elastic stage(very short);plastic platform stage,where the damage accumulated rapidly(very long);failure stage,where damage continued to develop.Based on the deformation and failure process of rock salt under uniaxial compression,a mathematical model of damage evolution was established.The reliability of the model was verified by the experiment,which could well reflect the stress-strain process and the damage evolution of ultra-deep rock salt in Qianjiang.In view of the splitting failure of the ultra-deep rock salt under uniaxial compression,the mechanical explanation was given.The research results have a certain guiding significance for the construction of underground salt cavern gas storage.