VARIABLE-ORDER FRACTIONAL CREEP MODEL OF MUDSTONE UNDER HIGH-TEMPERATURE

In order to study the properties of high-temperature creep for mudstone, MTS810 electro-hydraulic servo material test system and MTS652.02 high temperature furnace are utilized for the creep test of mudstone at 700 degrees C. Considering the visco-elastic-plastic characteristics and the damage effect, the variable-order fractional creep model is established to research the creep character, and it is found that the proposed model can be well fitting of our experimental results. Especially, variable-order function can be used to analyze and study the viscoelastic property evolution of mudstone in process of high-temperature creep. Compositions of mud stone are distinguished by X-ray diffraction technology. The presence of the illite under high temperatures can be used for explaining the viscous feature prevails over the elastic ones in viscoelastic properties.