Experimental Research on Creep Failure Characteristics of Gypsum Rock Based on Rock Longitudinal Wave Velocity

Abstract

Creep damage of rock is one of the fundamental factors that lead to collapse of large goaf in gypsum mine, and in different damage stage, rock wave velocity show out different characteristics. In the paper, microscopic characteristics of gypsum rock are analyzed by technology of electron microscope scanning. Then variation characteristics of gypsum rock wave velocity under uniaxial compression are tested, through rock servo experimental system and rock wave velocity testing instrument. Finally, relationship between variation characteristics of wave velocity,damage and destruction law of gypsum rock are studied, which under condition of graded incremental loading. Results show that damage of gypsum rock specimen is a “cumulative- extended” process, which is discontinuous change. Under creep condition, phenomenon of “sudden increase” of longitudinal wave velocity appears before critical failure, which is an important feature of creep failure of gypsum rock. And the value of creep failure strength is larger than that of uniaxial compression strength.