Abstract Effective volume reduction resulted by cavern shrinkage is one of the common risk types in the operation phase of salt cavern gas storage. Cavern shrinkage risk will lead to damage or collapse of cavern wall rock,even serious accidents. Aimed at the possible cavern shrinkage risk during operation phase of salt cavern gas storage,volumetric shrinkage formula of steady state creep phase is derived on the condition of spherical cavern with constant internal pressure in the limitless and ideal salt rock. Combined with the cavern shrinkage risk classification of salt cavern gas storage,the limit state equation of cavern volume shrinkage is created. On the assumption that every random variable in the limit state equation follows normal distribution,probability of risk occurrence under different levels is calculated using reliability analysis. Then the change regularity of stress-difference between grostress and internal pressure and risk probability of every level is analyzed. Lastly,the elastic deformation,initial creep deformation and accelerated creep deformation are taken into consideration and the calculations result is discussed. The research results can provide theoretical reference for the operation management of salt cavern gas storage.
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Received: 25 September 2011
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