Experimental study on coal mass strength and fragmentation characteristics under different loading rates
The uniaxial compression test of coal mass samples taken from Yuwang Coal Mine in eastern Yunnan mining area was carried out by Shimazu AG-Ⅰ 250 kN universal testing machine to investigate the strength characteristics and crushing characteristics of protru-ding dangerous coal mass samples under different loading rates.The test results show that the stress and strain curves of coal mass goes through three stages:linear elasticity,plasticity and post-peak failure,and the elastic characteristics become more and more obvious with the increase of loading rate.With the increase of loading rate,the peak strain of the coal mass increases,and the elastic modulus has a linear relationship with the loading rate.The failure mode of coal mass under uniaxial compression is often manifested brittle failure,with the increase of loading rate,the converted diameter of crushed coal sample decreases and the newly added surface area increases,the o-verall degree of fracture increases with the increase of loading rate,which is consistent with the macroscopic degree of coal mass failure.The strength characteristics of coal mass at different loading rates meet Coulomb criterion,and the peak strength and the time to reach the failure have a linear relationship with the loading rate.
loading ratestress and straincoal mass strengthconverted diameternewly added surface area
万方数据
维普
