突出煤岩纵波波速与应力相关关系

Correlation between longitudinal wave velocity and stress in outburst coal-rock

为探究井下煤与瓦斯突出灾害的发生机理并实现监测预警,运用微机控制电液伺服岩石试验机对突出型煤试样进行单轴加载破坏实验,分析了试样破坏特征及力学特性,采集震动波信号,与实际结果拟合后得到波速与应力的耦合规律,并建立了波速与应力间的试验关系模型,利用矿震信号进行了突出煤层震动波层析成像现场试验验证。结果表明,在单轴加载条件下,纵波波速与突出煤样应力之间存在指数函数关系Vp=a+ke rx,在加载初始阶段纵波波速变化梯度大,随后变化梯度逐渐减小并趋于线性,与实测值的相关系数计算结果表明模型相关度达0.883,能较准确描述波速与应力的变化关系。现场震动波层析成像得到的应力异常区域与现场采掘地质条件对应良好,验证了上述突出煤岩纵波波速与应力的正相关关系。震动波层析成像可应用于突出煤层应力集中区探测,对矿井突出危险区域预测具有重要的现实意义。

In order to explore the mechanism of coal and gas outburst disasters and to realize monitoring and early warning,the uniaxial compression failure test of the briquette coal samples was carried out by electro-hydraulic servo rock testing machine,and the failure characteristics and mechanical properties of the samples were analyzed.The P-wave generated during the experiment was collected to fit the actual shock wave,so as to discover the coupling law between wave velocity and stress and establish the experimental correlation model between them.Finally,the field test verification of mine tremor velocity tomography was conducted by the mine seismic signal.The results showed that under the condition of uniaxial compression,there was an exponential function relationship between P-wave velocity and stress V p=a+ke rx.At the initial stage of compression,the P-wave velocity changed greatly,and then the gradient gradually decreased and tended to linearity.The model correlation is 0.883,which could accurately describe the correlation between wave velocity and stress.The stress anomaly region obtained by mine tremor velocity tomography corresponded well with the on-site mining geological conditions,which verified the positive correlation between P-wave velocity and stress.Mine tremor velocity tomography can be applied to the exploration of stress concentration areas in coal seams,which has important practical significance for the prediction of mine dangerous areas.