doi:10.16186/j.cnki.1673-9787. 2021120121

Received:2021-12-30 00:00:00

Revised:2022-06-06 00:00:00

Online Date:2023-04-13

Experimental study on mechanical properties of coal specimens withdifferent moisture contents under uniaxial dynamic compression（Online）

ZHAI Xinxian, LIU Qinyu, ZHAO Xiaofan, REN Zhu’an, GUO Zhaoyang

School of Energy Science and Engineering，Henan Polytechnic University，Jiaozuo 454000，Henan，China

Abstract:At present，coal seam water injection in gateway is one of the effective technical measures to prevent coal bumps in longwall top coal caving mining. Raw coal samples were selected in the coal face of Gengcun Coal Mine in Yima mining area，China. The water absorption tests of coal specimens were carried out at laboratory，and cylindrical specimens with different moisture contents were made. SHPB dynamic impact compression tests were carried out. The influences of impact velocities and moisture contents of specimens on their dynamic mechanical properties were studied.The test results show that：（1）The moisture contents of specimens are positively correlated with their absorption times. Bound on the inflection points of water content-soaking time curves，the soaking process of specimens is divided into two stages，i.e.，the early absorption stage and the later absorption stage.（2）The dynamic mechanical parameters of specimens are related to their impact velocities and moisture contents.While the moisture contents of specimens are constant，dynamic compressive strength and dynamic elastic modulus are positively correlated with their impact ve⁃locities.While the impact velocities of specimens are constant，dynamic compressive strength and dynamicelastic modulus are negatively correlated with their moisture contents.（3）According to the yield strength and peak strength of specimens，the whole uniaxial dynamic stress-strain process of the specimens is divided into three deformation stages，namely，the elastic stage，the yield stage，and the strain softening stage.The stress-strain fitting equation for each stage of the specimens was regressed.The conclusions can providereference for the implementation and application of the measures of coal seam water injection by deep bore⁃holes to prevent coal bumps in coal mines.

 Key words:coal specimen;moisture content;dynamic load;SHPB;dynamic mechanical property

CLC:TD315