鉴于盐岩地下储库界面对储气(油)库稳定性和密闭性的重要影响,分别从细观和宏观方面对其变形与破损特性开展研究。细观方面:开展含界面盐岩的电镜扫描试验,分析表明:盐岩与夹层界面处颗粒结合紧密、相互嵌合,胶结良好,为储库密闭性提供有利条件。宏观方面:基于复合岩体理论构建层状盐岩交接界面的应力表达式,进而分析界面的变形及破损特性。分析表明,界面附近应力状态极为复杂,硬夹层对盐岩体具有约束锚固作用,且界面处易产生应力集中,进而诱发储库围岩体裂纹扩展直至破坏。综合细观、宏观分析表明,裂纹起裂机制和渗透通道形成是界面的细观结构特性及其应力状态共同影响的结果。研究成果为进一步分析地下盐岩储库的稳定性和密闭性提供一定参考。
For the significant influence of the interface between salt rock and interlayer on the stability and tightness of gas (oil) storage caverns in bedded salt rock, related research of meso and macro-aspects on the fracture properties of the interface has been launched. On meso-aspects, scanning electron microscope(SEM) has been carried out; and the results reveal that the grains embedded with each other very tightly so the cementation near the interface is good; it supplies advantageous guarantee for the tightness of the caverns. On macro-aspect, based on the mechanical theory of composite laminated rocks, the expressions of stresses near the interface of bedded salt rock have been established; and the characteristics of deformation and fracture of interlayer have also been analyzed. The research above indicates that the stress state of the interface is very complex. The anchoring effect of hard interlayer exerting to salt rock has been indicated; and the research also reveals that the stress concentration tends to occur near the interface between hard interlayer and salt rock. Combining the aspects of meso and macro together, the research shows that the mechanism of fracture initiation and propagation, and the formation of percolation paths, are induced by both the meso-structure properties and the macro stress state of the interface. The analysis provides some references for further study of the stability and tightness of storage caverns in bedded rock salt.