Experimental study of strength characteristics of water-saturated coal specimens under 3D coupled static-dynamic loadings
WANG Wen1,2,3,LI Huamin1,GU Helong1
(1. School of Energy Science Engineering,Henan Polytechnic University,Jiaozuo,Henan 454003,China;
2. Research Center of Coal Resources Safe Mining and Clean Utilization,Liaoning Technical University,Fuxin,Liaoning 123000,China;3. Shanxi Coal Import and Export Group Co.,Ltd.,Taiyuan,Shanxi 030006,China)
Abstract:In order to study the mechanical properties of water-saturated coal specimens under coupled static-dynamic loadings,contrast experiments between 3D coupled static-dynamic loadings and 3D static loadings on both water-saturated coal specimens and natural coal specimens were conducted by using the improved split Hopkinson pressure bar(SHPB) and the RMT–150 test systems. Results shows that,under 3D static loadings,the variation of peak strength of natural coal specimens is 10.49%,while the variation of peak strength of 7 d saturated specimen is 59.98%,with a softening coefficient of 0.81. Under 3D coupled static-dynamic loadings,when the axial pressure is less than 55% of the uniaxial compression strength,the dynamic strengths of the 7 d saturated coal specimens are higher than those of the natural coal specimens,the increased strength of 7 d saturated coal specimens are 7.85%–18.44%(confining pressure 4 MPa) or 8.71%–19.84%(confining pressure 4 MPa) compared to the natural coal specimens. In the case of different confining pressures with the same axial pressure,with the increase of confining pressure,the dynamic strengths of the 7 d saturated and the natural specimens are both increased. Moreover,the increment of dynamic intensity of 7 d saturated coal specimens is larger than that under the natural state,indicating that water-saturated coal specimens are more sensitive to confining pressure. Experimental results show that the effect of water-saturation to the strength of coal specimen is significant,but the strain rate plays a controlling role. The coupling effect between the water and coal fissure causes the larger stiffness under the conditions of medium or high strain rate. The dynamic strength of water-saturated coal specimens increases under 3D static-dynamic loadings.
王 文1,2,3,李化敏1,顾合龙1. 三维动静组合加载含水煤样强度特征试验研究[J]. 岩石力学与工程学报, 2017, 36(10): 2406-2414.
WANG Wen1,2,3,LI Huamin1,GU Helong1. Experimental study of strength characteristics of water-saturated coal specimens under 3D coupled static-dynamic loadings. , 2017, 36(10): 2406-2414.
ROSS C A,JEROME D M,TEDESCO J W,et al. Moisture and strain rate effects on concrete strength[J]. ACI Material Journal,1996,93(3):293-300.
Your browse does not support frame!