Probability distribution of creep parameters of salt rock based on entropy theory

On the basis of creep test data and creep variation trend of salt rock at the location of a proposed gas storage, the creep parameters of such rock salt are obtained by Burgers creep model fitting. The maximum entropy principle is applied to analyze the probability distribution of the creep parameters. Using each central moment of the test data of the creep parameters and the central moment information after the data taking logarithm as constraints, the maximum entropy model for the probability distribution of the creep parameters is established and the density distribution function of the creep parameters is worked out. Different entropy density functions are got by modeling under different constraints, to build relative entropy formula for entropy probability function and the empirical distribution function, and then to select which is more accord with the actual density function by comparative analysis of the relative entropy values. The results show that the probability distribution model of salt rock creep parameters established on the basis of entropy theory can make full use of the information provided by the test data, and effectively avoid the adverse impact on the results of the probability distribution of the parameters due to subjective identification or assumption.