瓦斯压力对突出煤层煤样力学特征影响规律的研究

Study on influence law of gas pressure on mechanical characteristic of coal samples in outburst coal seam

为了研究瓦斯气体对煤岩力学参数及动力灾害的影响,选取贵源煤矿2号井9~#煤层为研究对象,设计了含瓦斯煤岩单轴压缩试验装置,利用RMT-150C力学试验机对煤岩在不同瓦斯压力条件下的力学特性开展试验。研究结果表明,瓦斯压力对煤的单轴抗压强度、应力—应变曲线及弹性模量存在显著影响。煤的单轴抗压强度及弹性模量与瓦斯压力呈负相关关系;瓦斯压力为0、0.5、1.0、1.5、2.0 MPa时煤样的平均抗压强度分别为24.37、19.37、12.78、10.40、7.35 MPa,平均弹性模量分别为3.388、3.359、2.614、2.124、1.143 GPa;与不含瓦斯煤样相比,瓦斯压力为0.5、1.0、1.5、2.0 MPa时煤样的单轴抗压强度分别降低了20.52%、47.56%、57.32%、69.84%,弹性模量分别下降了0.86%、22.85%、37.31%、66.26%。随着瓦斯压力逐渐增大,煤岩由脆性向延性逐渐转变,冲击性逐渐降低。研究结果有助于进一步揭示贵州地区煤与瓦斯突出事故频发的内在原因。

In order to study the influence of gas on mechanical parameters and dynamic disasters of coal and rock, the No.9 coal seam of No.2 well in Guiyuan Coal Mine was selected as the research object, the uniaxial compression test device of gas bearing coal and rock was designed, and the mechanical properties of coal and rock under different gas pressure were studied by using RMT-150 C mechanical test machine. The results show that the gas pressure has a significant effect on the uniaxial compressive strength, stress-strain curve and elastic modulus of coal. The uniaxial compressive strength and elastic modulus of coal are negatively correlated with gas pressure;when the gas pressure is 0 MPa, 0.5 MPa, 1.0 MPa, 1.5 MPa and 2.0 MPa, the average compressive strength of the coal sample is 24.37 MPa, 19.37 MPa, 12.78 MPa, 10.40 MPa and 7.35 MPa, respectively, and the average elastic modulus is 3.388 GPa, 3.359 GPa, 2.614 GPa, 2.124 GPa and 1.143 GPa, respectively;compared with coal samples without gas, when the gas pressure is 0.5 MPa, 1.0 MPa, 1.5 MPa and 2.0 MPa, the uniaxial compressive strength of coal samples decreases by 20.52%, 47.56%, 57.32% and 69.84%, and the elastic modulus decreases by 0.86%, 22.85%, 37.31% and 66.26%, respectively. With the gradual increase of gas pressure, coal and rock change from brittleness to ductility, and the impact decreases gradually. The results are helpful to further reveal the internal causes of frequent coal and gas outburst accidents in Guizhou.