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为深入认识含气页岩力学各向异性及其变形特征,选取典型地表露头页岩,沿与页岩原生层理面呈不同夹角方向取芯,进行纵波波速测试、单轴压缩试验、三轴压缩试验,主要研究含气页岩固有的各向异性及其强度、变形、破裂特征。结果表明:页岩是一种脆性层状岩石,其纵波速度、弹性模量、抗压强度随钻芯角度φ不同存在显著的各向异性;页岩原生层理弱面和围压对其变形、破裂形态有很大影响。纵波速度、弹性模量随钻芯角度φ的增加而降低,抗压强度受弱面影响较大,泊松比变化不明显。单轴压缩时,页岩层理弱面对其破裂形态影响很大,弱面开裂与层间剪切破坏共存;三轴压缩时,围压对其破裂形态影响较大,破裂方式以剪切破裂为主。
In order to understand the mechanics anisotropy of gas shale and its deformation characteristics, the typical representative shale heads were selected and taken coring at different included angles with the original bedding plane of shale. The longitudinal wave velocity test, uniaxial compression test, Axial compression test, mainly study the inherent anisotropy of gas shale and its strength, deformation, rupture characteristics. The results show that shale is a brittle layered rock and its longitudinal wave velocity, elastic modulus and compressive strength have significant anisotropy with different core angle φ. Shale is deformed by weak surface and confining pressure , Rupture morphology has a great impact. P-wave velocity and elastic modulus decrease with the increase of the core angle φ. The compressive strength is greatly affected by the weak plane, and the change of Poisson’s ratio is insignificant. In the uniaxial compression, the weak face of shale layer has a great influence on its rupture morphology, and the weak face cracking coexists with the interlaminar shear failure. Under triaxial compression, confining pressure has a great influence on its rupture morphology, and the rupture mode is shear fracture Mainly.