Experimental study on tensile and compressive mechanical properties of coal samples under influence of water content

doi:10.16265/j.cnki.issn1003-3033.2024.06.0104

Abstract

Abstract:

In order to reveal the effect of water content on the tensile and compressive mechanical properties of coal samples, coal samples from the No.22 seam of the Hanjiawa coal mine were selected. Brazilian disc splitting tests, uniaxial compression tests, and triaxial compression tests were conducted on coal samples with different moisture contents and confining pressures to explore the mechanical characteristics of water containing coal samples. The results show that the strength and elastic modulus of coal samples decreases exponentially with increasing water content. When the coal samples reach saturation, the strength and elastic modulus decrease by 48.3% and 37.6% respectively. With the increase in water content, the plasticity of coal samples is enhanced, and the samples are prone to breakage. Under triaxial compression, the peak value of failure and the strength of coal samples increase with the increase of confining pressure. However, the strength of water-bearing coal samples under different confining pressures is obviously lower than that of dry coal samples. The water content has little effect on the internal friction angle of coal samples but has a significant effect on the cohesive force of coal samples.

Key words: water content, coal sample, tensile, compression test, mechanical property

CLC Number:

X936

ZHANG Meichang, BAI Chenhao, QI Yun, WANG Wei, XUE Kailong, REN Jiewei. Experimental study on tensile and compressive mechanical properties of coal samples under influence of water content[J]. China Safety Science Journal, 2024, 34(6): 146-156.

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试样编号	直径/ mm	长度/ mm	含水率/ %	峰值载荷/kN	抗拉强度/MPa
BD-1	49.57	26.63	0	4.29	2.07
BD-2	49.69	25.633	0	3.82	1.91
BD-3	49.50	26.36	0	3.59	1.75
平均值	—	—	—	3.90	1.91
BDW1-1	49.60	25.14	1.76	2.23	1.14
BDW1-2	49.47	25.33	1.70	2.20	1.12
BDW1-3	49.79	25.11	1.81	2.57	1.31
平均值	—	—	—	2.33	1.19
BDW2-1	49.51	26.67	3.62	1.56	0.75
BDW2-2	49.75	26.40	3.58	1.94	0.94
BDW2-3	49.69	27.03	3.57	1.90	0.90
平均值	—	—	—	1.80	0.86

编号	直径/ mm	长度/ mm	含水率/%	围压/ MPa	强度/ MPa	弹性模量/GPa
DC-4	49.81	99.16	0	2	61.8	4.1
DC-5	49.79	100.15	0	4	66.7	3.8
DC-6	49.75	94.65	0	6	75.7	4.1
DC-7	49.78	97.77	0	10	85.6	4.0
WC1-4	49.81	99.96	1.69	2	48.7	3.0
WC1-5	49.78	100.23	1.78	4	63.8	2.9
WC1-6	49.82	100.17	1.77	6	70.3	3.0
WC1-7	49.85	100.11	1.82	10	75.4	3.2
WC2-4	49.83	100.06	3.57	2	40.6	2.2
WC2-5	49.78	101.22	3.56	4	50.8	2.5
WC2-6	49.81	100.08	3.52	6	58.3	2.6
WC2-7	49.80	100.35	3.62	10	67.2	2.9