Abstract: The strength of filling body is the key to the development of filling mining technology,and the change of loading rate will affect the strength characteristics of the filling body.Thus,uniaxial compressive strength tests with different cement sand ratio filling block under different loading rates were carried out.Results showed that the strength of filling body firstly increased and then decreased with the increase of loading rate.The maximum strength of the filling body depended on the critical loading rate.Below the critical rate,the strength of the filling body increased with the increase of the rate,but beyond the critical rate,the strength of the test blocks decreased with the increase of the rate.The rapid loading rate limited the development of the internal crack and pore of the filling body,and lowered the strength weakening effect.Meanwhile,the rapid loading rate accelerated the energy accumulation and dissipation process of filling body,shortened the elastic stage of the test blocks.After accumulating more elastic at the pre peak,the test blocks can reach peak axial stress earlier.

Key words: Filling body, Loading rate, Compressive strength, Elastic energy