岩石强度对于组合试样力学行为及声发射特性的影响

为研究岩石强度对煤、岩体整体失稳的影响,测试并研究了不同组合煤岩试样单轴压缩过程的破裂形式、应力应变特性、试样强度、声发射特性等规律,分析了岩石强度对于组合试样力学行为的影响。结果表明:组合试样应力-应变曲线位于煤体和岩石之间,更加靠近煤体;随着岩石强度的升高,组合试样从屈服到达峰值的速度越来越快;煤体相同条件下,岩石的强度较低时,组合试样裂纹会向岩石内扩展,同时岩石发生拉伸破坏,岩石强度较大时,破裂主要发生在煤体内;组合煤岩试样屈服点和峰值的应力比值相差不大,屈服点和峰值的应变比值随岩石强度的升高不断升高,两者比值和岩石强度呈线性关系;组合试样峰值应力处声发射信号能量值和脉冲值随岩石强度的增加呈线性升高。

Effects of rock strength on mechanical behavior and acoustic emission characteristics of samples composed of coal and rock

In order to study the effect of rock strength on the overall instability of coal and rock，different coal and rock composite samples were tested under uniaxial compression condition，and the failure mode，stress-strain characteristics，uniaxial compression strength and acoustic emission characteristics during the uniaxial compression process were researched，besides，the effect of rock strength on mechanical behavior of composite samples was analyzed.The results show that the stress-strain curve of composite sample situates between that of the rock and the coal but closer with the coal stress-strain curve.With the increasing of rock strength，the rate of the combination sample from yield to peak is faster and faster.When the rock strength is low，the crack propagation in coal body expands to the rock，and tensile failure happens to the rock.With the same coal in the composite samples，when the rock strength is high，rupture occurs mainly in the coal.The ratio of yield point stress and peak stress of composite samples vary quite little with each other，the ratio of yield point strain and peak strain increases with the rising of the rock strength，and the ratio has linear relationship with rock strength.The energy and pulse of acoustic emission signals at the peak strength point of the combination sample increase linearly with rock strength rising.