Experimental Investigation And Theoretic Analysis On The Mechanical Properies Of Layered Rock Salt

Nowadays, energy conjuncture is obviously, energy storage become more and more vital. There are many advantaged factors such as high safety on deeply space as a medium for energy storage. Considering the geological formation characteristics of most salt mines in our country, Systemic experimental investigation and theoretic analysis on the mechanical aspects of layered rock salt (rock salt layer with mudstone interlayer) and rock salt and mudstone have been conducted in the dissertation. The analysis results presented may provide experimental basis and mechanical parameters for further study of the stability of the oil/gas storage cavern in layered salt rock formation. There are three aspects for experimental studies and theoretic analysis of the rock salt:(1) Brazilian Test and Direct Shear Test. Testing studies of brazilian test and direct shear test were carried out on the interface of rock salt and mudstone in layered rock salt, it was found that the interface have strong adhesion and don't a soft face. By the results of direc shear test, the strength parameter: C andφof the interface of rock salt and mudstone in layered rock salt samples and rock salt and mudstone are obtained, the numerical value of C andφof the interface of rock salt and mudstone in layered rock salt is close to the rock salt and mudstone. The micro-analysis of granular cementation of the interface of rock salt and mudstone in layered rock salt have been done by scanning electronic microscope.(2) Uniaxial and Triaxial Compress Experiment. Testing studies of uniaxial and conventional triaxial compression were carried out on layered rock salt and rock salt and mudstone, the analysis on properties of the short-term strength and deformation of three samples was conducted. The experiments showed that the uniaxial and conventional triaxial compression failure mode of three samples is obvious different, the presence of mudstone interlayer affects the failure characteristics of layered rock salt remarkably, an analysis on uniaxial and conventional triaxial compression failure mechanism of layered rock salt was conducted basis on the linear elastic theory, The theoretical results indicated it is the match of failure characteristics of layered rock salt. Hoek-Brown failure theory was more compatible with three samples than Mohr-Coulomb failure theory.(3) Uniaxial and Triaxial Creep Test. The analysis on properties of the creep deformation of three samples are conducted, the creep deformation of layered rock salt was similar to rock salt, with the same stress state the steady state creep strain rate of mudstone was lower a order of magnitude than rock salt. The long-term strength of three samples were obtained through the way of dilatancy. A creep constitutive model of rock salt is made by using visco-elastic-plastic theory. Finally, the parameters of constitutive equation are obtained by fitting test data, the theoretic results is proved well by comparison with the experimental results.