Abstract: To study the long-term strength characteristics of filling paste in coal mine, the uniaxial compression experiments and creep experiments of filling paste specimens have been performed. The weight ratio of cement, fly ash to coal gangue has been 1∶4∶6 in those specimens. The physical characteristics, instantaneous deformation modulus and other features of filling paste specimens have been analyzed based on the experimental results. The results have shown that filling paste has poor density and strong compressibility, and the internal structure of filling paste becomes homogeneous and dense during the slow loading process. Under each stress level of creep experiments, the instantaneous deformation modulus of filling paste increases gradually with the enhancements of stress and deformation before the failure of specimens, and the growth rate is 1.77×10 5 %. At the same time, the strain rates in elastic strain stage decrease gradually. The results have also indicated that the creep strength is higher than uniaxial compressive strength, the average creep coefficient is 1.09, and that the macroscopic strength hardening has occurred in creep experiment.

Key words: filling paste, creep experiment, instantaneous deformation modulus, strain rate, hardening mechanism, macroscopic hardening