关键词: 盐岩, 初始损伤, 保压时间, 裂隙发育度, 损伤愈合

Abstract: The aim of this study is to investigate the damage recovery effect of salt rock under confining pressure conditions. Thus the damage recovery experiments have been performed on the salt rock specimens with different initial damage degrees under different confining pressures and holding time. Based the controlling theory of strain, the effects of the above three factors on the strain and damage recovery are analyzed under compression. The results indicate that the self-recovery ability of salt rock can be changed by confining pressure. The strain recovery process can be divided into three phases: fast recovery, retard recovery and slow recovery which are depending on the confining pressure, degree of growing cracks and holding time . Firstly, it is shown that the strain recovery process can be approximately fitted by a negative exponential function. Secondly, the increases of both holding time and confining pressure are beneficial to the effects of strain and damage recovery to a certain degree. Especially, the increase of confining pressure within the holding time can not only raises the whole recovery rate, but also prolongs the retard recovery stage. Finally, the ranking of damage magnitudes of salt rock specimens remains unchanged, even though the specimen with a higher damage degree has a high recovery rate in the pressure holding time. The high confining pressure can promote the strain and damage recovery of salt rock, but a higher confining pressure may cause the phenomenon of false recovery.

Key words: salt rock, initial damage degree, holding time of pressure, fracture development, damage recovery