基于图形测量技术的煤岩力学三轴试验研究

Research on Triaxial Test of Coal Rock Mechanics Based on Graphical Measurement Technology

为研究初始围压对煤岩力学特性的影响,以王庄煤矿9105工作面煤体为研究对象,通过HC-SPT-100型高压三轴试验机、HC-U7型非金属超声波探测仪、4K科研相机等仪器,利用数字图像测量技术开展不同初始围压下原煤试件加载试验,探究不同围压对煤体弹性模量、峰值应变、残余应力和破坏裂隙的影响规律,研究结果表明:弹性模量、峰值应变和残余应力随围压的增大而增大;随围压的增大各峰值应变增长速率不同,轴向峰值应变增长速率最快,体峰值应变增长速率次之,径向峰值应变增长速率最慢;不同围压加载破坏下煤体裂隙特征明显,主要以斜交裂隙为主;采用Jaeger法求得不同围压下煤岩体破坏临界强度值与试验值比较误差较小,符合Jaeger单结构面理论.

In order to study the effect of initial confining pressure on the mechanical properties of coal and rock,the coal body of Wangzhuang Coal Mine 9105 working face was taken as the research object.Using HC-SPT-100 high pressure triaxial shear test machine,HC-U7 non-metallic ultrasonic detector,4K scientific research camera and other instruments,the loading experiments of raw coal specimens under different initial confining pressures were carry out,and the effects of different confining pressures on the elastic modulus,peak strain,residual stress and failure cracks of coal body were studied.It shows that the elastic modulus,the peak strain and the residual stress increase with the increase of confining pressure.As the confining pressure increases,the growth rate of each peak strain is different.The axial peak strain growth rate is the fastest,followed by the volumetric peak strain growth rate,and the radial peak strain growth rate is the slowest.Under different confining pressures,the fracture characteristics of coal body are obvious,mainly consisting of oblique cracks.The error between the critical strengths of coal rock under different confining pressures obtained by Jaeger's method and the experimental values is small,which is consistent with Jaeger's single structural surface theory.