采动裂隙煤岩破裂能量耗散特性及机理

Energy dissipation properties and mechanisms of fractured coal-rock mass failure under mining condition

乌鲁木齐矿区主采水平已进入深部开采,高应力强卸荷下动力破坏现象频发。为建立裂隙煤岩耗散能与声发射能量参数的定量关系,更好地了解煤岩体受载破裂特征,揭示高应力下裂隙煤岩破裂能量耗散及其灾变机制,本文采用实验手段分析单轴压缩荷载作用下裂隙煤岩体损伤直至破裂的阶段性特征及其能量释放规律,结果表明:裂隙煤岩物性特征一致性较好,其力学参数离散性大,裂隙煤岩的力学响应特征为非线性本构关系,峰后的应变值应只考虑屈服弱化区域的塑性应变;煤岩样破裂过程可划分为4个阶段:初始受载阶段、弹性阶段、微破裂阶段与峰后破裂阶段;给出了基于声发射能量参数的裂隙煤岩破裂耗散能的理论计算模型,确定了裂隙煤岩破裂应变能与弹性应变能及E_(AE-Ⅱ)/ΣE_(AE)间的关系,研究结果表明裂隙煤岩破裂所耗散的能量随着E_(AE-Ⅱ)/ΣE_(AE)的增加而减少。

Mining level in the Urumqi coal field is now in deep mining. A lot of dynamic failure events take place frequently due to the high-stress. In order to establish quantitative relationship between the dissipated energy of unloading coal-rock masses and AE energy parameters, fracturing characteristics of coal-rock mass under loading are clear shown well. This paper offers an experimental method to analyze stage traits and energy release mechanism from damage to fracture of coal-rock masses under uniaxial compressed loading. The research results indicate that physical-property consistency of the fractured coal-rock masses is preferable but the coal-rock masses has large mechanical-property discreteness. Constitutive relation of the fractured coal-rock masses is nonlinear and strain value after the peak is only plastic strain in yield weakening zone. The process of coal-rock specimens can be classified into four stages including the initial loading stage, the elastic stage, the micro-fracturing stage and the post-peak fracturing stage. Theoretical calculation model for energy dissipation of the fractured coal-rock masses is provided based on AE energy parameters. The quantitative relation contains crucial parameters in cluding strain energy, elastic energy and EAE-Ⅱ/ΣEAE. The dissipated energy of coal-rock mass decreases obviously with EAE-Ⅱ/ΣEAE increasing.