ZHAI X X, LIU Q Y, ZHAO X F,et al.Experimental study on mechanical properties of coal specimens with different moisture contents under uniaxial impact[J].Journal of Henan Polytechnic University(Natural Science) ,2023,42(5):18-28.

doi:10.16186/j.cnki.1673-9787.2021120121

Received:2021/12/30

Revised:2022/06/06

Published:2023/09/25

Experimental study on mechanical properties of coal specimens with different moisture contents under uniaxial impact

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 Geng Village in Yima mining area，China.The water absorption tests of coal specimens were carried out at laboratory，then cylindrical specimens with different moisture contents were made.The Hopkinson（SHPB）uniaxial impact compression tests were carried out to study the influence of impact velocity and moisture content of specimens on their dynamic mechanical properties.The test results showed that：（1）The moisture content of specimens was positively correlated with their soaking time.Bound on the inflection points of water content-soaking time curve，the soaking process of specimens was divided into two stages，namely the early soaking stage and the late soaking stage.（2）The dynamic mechanical parameters of specimens were related to their impact velocities and moisture content.While the moisture content of specimens was constant，dynamic compressive strength and dynamic elastic modulus were positively correlated with their impact velocity.While the impact velocity of specimens was constant，dynamic compressive strength and dynamic elastic modulus were 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 was 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 could provide reference for the implementation and application of the measures of coal seam water injection by deep boreholes to prevent coal bumps in coal mines.

Key words:coal specimen;uniaxial impact;impact velocity;moisture content;SHPB;dynamic mechanical property

不同含水率煤样单轴冲击力学性质试验研究_翟新献.pdf