Experimental Study on Creep Characteristics and Long–Term Strength of Anthracite

Coal pillars from old mines undergo creep, a type of time?dependent deformation. Research on underground engineering stability coal has increasingly focused long?term strength as an important mechanical index the creep characteristics pillars. This study performed conventional triaxial compression and tests anthracite under different confining pressures. The law was studied according to test results. results demonstrated following: (1) elastic modulus peak strain increased exponentially with pressure. (2) Under low stress levels, exhibited only instantaneous deformation attenuation creep. In contrast, deformation, steady high levels; accelerated occurred until failure when reached particular value. (3) By fitting steady?state rate functional relationship between axial established, threshold in high?stress?level areas suggested optimum anthracite. (4) ratio various pressure grades ranged 70% 91%.