Linkage-based device for creep testing of coal rock

The creep properties of coal rock have been extensively investigated under conventional uniaxial stress conditions, whereas few studies have considered its characteristics or the process of seepage under triaxial stress. This study proposes and verifies a linkage-based creep test device for coal rock to study its creep characteristics under triaxial stress. The deformation, pressure, and signals of acoustic emission under triaxial stress were measured by using a specially designed data measurement system. The experimental device uses the connecting rod loading mechanism for continuous constant pressure loading. Through theoretical calculations and finite element analysis, the authors show that the strength and stiffness of the device satisfy the requirements of a maximum load of 300 kN. A creep test was carried out to verify the operation of the proposed device and analyze the creep characteristics of sandstone under different confining pressures. The results show that the device can analyze the catastrophic characteristics of sandstone, and this proves its validity and reliability in terms of monitoring the continuous pressure or constant pressure of sandstone during creeping. The device provides a new method to study the creep properties of coal rock under different stresses and seepage conditions.