饱水煤岩基本力学性能的试验研究

Experimental Study on Basic Mechanical Properties of Water-saturated Coal

利用MTS电液伺服岩石试验系统对煤岩试件进行了饱水与自然两种状态下的单轴压缩与拉伸试验,结果发现,与自然状态煤样相比,饱水煤样单轴抗压强度降低了26.71%,弹性模量降低26.85%,轴向应变增大,普氏系数与泊松比均有所降低;饱水煤样抗拉强度平均降低43.86%,且破坏时间大为缩短。此外,煤岩单轴压缩与拉伸试验曲线均呈锯齿状,其中煤岩单轴压缩过程依次经历裂隙压密、表观线弹性变形、弹塑性变形以及断裂破坏4个阶段,拉伸试验中煤岩受力呈线性增加直至弹脆性拉断,失稳破坏瞬间发生。

The uniaxial compression and tensile tests of coal samples in both water-saturated and natural states were carried out with MTS electro-hydraulic servo rock test system, it was found from the test results that the uniaxial compressive strength of water-saturated coal samples decreased by 26. 71% as compared to that in natural state, the elastic modulus decreased by 26. 85%, the axial strain increased, and the hardness coefficient and Poisson’ s ratio decreased to some extent; the tensile strength of water-saturated coal samples decreased by 43. 86% on an average and the damage time greatly shortened. In addition, the uniaxial compression and tensile test curves of coal samples were all in jagged forms, the uniaxial compression course of coal samples successively went through four phases, including the fissures compaction, the apparent line elastic deformation, the elastic and plastic deformation and the failure, and in the tensile test, the force exerted on coal samples increased linearly until the instability failure occurred instantaneously.