Abstract: In order to understand the self-healing property of the damaged salt rock in excavation disturbed zone (EDZ) during the utilization of salt cavern, self-healing experiments of damaged salt rock under the effect of the brine soaking and drying were carried out. The results are as follows. The mechanical properties of the damaged salt rock can be recovered after being soaked in brine and dried at different temperatures. The recovery effect increases with the increase of temperature in the test temperature range 35-80℃. The acoustic emission characteristics of the damaged salt rock specimen during the secondary loading process after healing show that the Felicity ratio is less than 0.1. It can be concluded that the Kaiser effect is not established, which indicates that part of the damage of the salt rock can heal at the mesoscopic scale during the self-healing process. Based on the mesoscopic morphology characteristics of the salt rock specimens after healing, three different physical mechanisms of damage healing in rock salt are summarized: healing of microcracks based on diffusion, filling of microcracks based on crystallization of NaCl crystal, healing of the boundaries of crystal in the crushing zone. During the process of salt rock damage healing, the brine filled in the cracks not only provides a channel for the material transfer but also provides a number of base material for crystalline, which lays the foundation for damage healing. The increasing temperature provides more energy for the healing and increases the recrystallization density, improving the speed and the degree of damage healing.

Key words: salt cavern, rock salt, excavation disturbed zone (EDZ), damage healing