Abstract During construction of bedded salt cavern,the handing interlayer collapses periodically as the size of salt cavern expands. Meanwhile,gypsum interlayer has varying degree of weakening when soaked in brine with different temperature and different concentration. It can cause the pipeline to break and fracture. Moreover it has a dramatic impact on the shape and speed of construction of salt cavern. The problem is the research background of mechanism of interlayer's collapse. Based on the theory of annular plate, a mechanical model for the analysis of the gypsum interlayer's collapse is established. Besides, the non-bucking failure and bucking failure of annular plate are analyzed in this paper. Finally, the concept of periodic caving pace and the flowchart of calculating is proposed. The flowchart is applied to measure to the failure characteristics of gypsum interlayer. Through the theory and simulation analysis and example demonstration,it was showed that the periodic caving pace decrease gradually with the increasing area of salt cavern. Periodic caving times was affected by temperature and concentration of brine. The caving pace of gypsum interlayer which not be soaked in brine was reduced to 8.50 m from 12.00 m and collapsed three times. However, the caving pace of gypsum interlayer which be soaked in hot brine (70 ℃) was reduced to 1.98 m from 4.05 m and collapsed seven times. Periodic caving times increased with the increase of temperature and concentration of brine.
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