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基于不同层理角度的页岩巴西劈裂试验,利用高速摄像系统和声发射系统,对页岩力学特性、裂纹扩展及声发射特征的层理效应进行了深入研究。结果表明:(1)页岩巴西劈裂破坏过程可以分为压密、弹性和破坏3个阶段;(2)页岩抗拉强度、劈裂模量和应力峰值时变形的各向异性特征明显,层理角度??30°时,层理效应最为明显,??90°时影响最小;(3)??0°和??15°时试样的裂纹破坏面基本是沿着层理面,??30°时裂纹面交切层理面,与加载基线面重合,??45°~90°的各试样的断裂面呈不同程度的偏离加载基线面,为弧面或曲面;(4)??30°和??45°为破坏机制转化角,其中??30°为沿着层理面压致性张拉开裂转化为交切层理面开裂的转化角,??45°为交切层理面开裂转化为交切层理面且沿着层理面不同程度的剪切滑移开裂的转化角;(5)声发射活动性和能量释放随层理角度的增加而加强,主要因为受层理角度的影响,其破坏机制不同,这也进一步验证了页岩随层理角度的变化,其破坏机制的各向异性。能率峰值与抗拉强度具有很好的线性关系,表明声发射能率峰值能很好地反映岩石抗拉伸破坏的程度。
Based on the shale Brazilian splitting experiment with different bedding angles, the layered effect of shale mechanical properties, crack propagation and acoustic emission characteristics was studied by using high-speed camera system and acoustic emission system. The results show that: (1) Brazil shale failure process can be divided into three stages of compaction, elasticity and failure; (2) the anisotropy of shale tensile strain, splitting modulus and stress peak is obvious , The bedding effect is the most obvious when the bedding angle is 30 °, and the least is the effect when the angle is 90 °. (3) The crack damage surface of the specimen at 0 ° and 15 ° is basically along the bedding plane , The intersection of the intersection of plane and the intersection of surface and the intersection of crack and surface at 30 °, coincide with the base line of the load, the fracture surface of each sample of 45 ° ~ 90 ° deviates to different degrees from the baseline surface, 4) 30 ° and 45 ° are the transformation angles of the failure mechanism, where 30 ° is the transformation angle of laminar plane tension-induced cracking and cracking to intersecting bedding plane cracking, (5) Acoustic emission activity and energy release increase with the increase of bedding angle , Mainly due to the influence of the layering angle and the different failure mechanisms. This further verifies that the shale changes with the layering angle and the failure mechanism is anisotropic. Peak energy rate and tensile strength have a good linear relationship, indicating that the peak acoustic emission energy can well reflect the degree of rock tensile damage.