In order to determine the long-term mechanical properties of surrounding rock of salt cavern gas storage, long tri-axial creep test studies on rock salt of the field were carried out. Based on the test data, long-term strength of rock salt was determined, and comparatively analysis was conducted combined with of the instantaneous test. The study results show that: Considering the axial strain, radial strain and volumetric strain to determine the long-term strength of rock salt can ensure reliability of the results. Under the same condition, the less salt content, the value of long-term strength is higher. Tri-axial creep process has a different effect degree between cohesion and internal friction angle; it is more sensitive to cohesion. The strain limit should be considered for the stability analysis of multi-bedded salt cavern gas storage construction and pay more attention about the mechanical properties of the interlayer parts. The study results provide references for researching the surrounding rock long-term mechanical properties of salt cavern gas storage.

According to salt rock creep test data and strain variation regulation of a salt mine, salt rock creep parameters are obtained based on Burgers creep model fitting. Statistical study of the probability distribution of the salt rock Burgers model creep parameters is carried out by K-S, A-D and C-M test method, from which probability model for each creep parameters is obtained. To achieve the purpose of determining the optimal probability model for each creep parameters, considering the acceptable level of various test method to different hypothesis probability model, the author put forward the comprehensive optimal acceptance criteria on the basis of limited comparison method, the correctness of which is proved by test result.

In this paper, two calcined Zhejiang diatomite and Jilin diatomite were modified by organic amine, polyethylene glycol, organocationic ions, organofunction group and metallic ions to adsorption and immobilize enzyme, the different organo-function group and metallic ions lead to the capacity of adsorptive enzyme changing with the variation of IEP value.

The effects of loading rate on splitting test, uniaxial compression strength, strength parameters in triaixal compression test, and creep failure of Hangcheng coal rock were investigated through indoor mechanical experiments. Experimental results shown that tensile strength, uniaxial strength and Youngs modulus of coal rock increased with the increase of loading rate and the increment is very small. Triaixal compression strength and loading rate has a linear relation. Brittleness was very marked under high loading rate. Ductility of coal rock in the steady creep stage diminished with the increase of loading rate, and failure mode of coal rock had a change from low ductility failure mode to ductile-to-brittle failure mode. The results of experimental researches can be used to determine the bottom hole flowing pressure of coalbed methane well.

To build a stress-strain-time relationship of salt rock with unified instantaneous law and creep law, we combine the stress-strain curve with whole process of creep curve, looking for inner relation between softening curve and creep deformation. Finally, the stress-strain-time space surface is obtained. The researching results demonstrated that time and space development law of rock salts can be well reflected by it.