为了研究板岩三轴蠕变特性,根据层理方向,对板岩进行0°和90°制备岩样,然后分别进行5 MPa、15 MPa和20 MPa围压的三轴蠕变试验.试验结果显示:围压和层理面是板岩蠕变的影响因素,围压越大,板岩的弹性模量和峰值强度越大.15 MPa围压下弹性模量和峰值强度各向异性度最大.同一围压下,平行层理面的峰值强度和弹性模量比垂直层理面的大.应力-应变曲线呈"厂"字形,板岩在低应力水平下蠕变很小,在临近破坏的高应力水平下有明显蠕变现象.围压越低,蠕变现象越明显,垂直层理面比平行层理面更易发生蠕变破坏.板岩每级加载都会出现瞬时应变且近似呈线性变化.板岩在最后一级加载下经历了初期蠕变、稳态蠕变和加速蠕变,在5 MPa和15 MPa围压下稳态蠕变期间有突变蠕变.板岩蠕变破裂形式主要沿层理面发生破坏,在低围压下附带张拉破坏,在高围压下附带剪切破坏.%In order to study the triaxial creep characteristics of slate,and according to the bedding direction,0° and 90°slate rock samples are prepared, then triaxial creep test are conducted under the confining pressure of 5 MPa,15 MPa and 20 MPa.The results show that confining and bedding are the influencing factors of slate creep, with the confining pressure increases,the elastic modulus and the peak strength of slate get greater.The degree of anisotropy is the greatest with the confining pressure of 15 MPa.With the same confining pressure, the peak strength and elastic modulus of parallel bedding are greater than those of vertical bedding.The stress-strain curve like a Chinese word"chang",the slate creeps slowly under the low stress level,and creeps obviously when comes to the high stress level.The lower the confining pressure is,the more obvious the creep phenomenon is,the verti-cal bedding samples are more prone to creep damage than parallel bedding.The instantaneous strain which shows approximate linear change is found in each stage of slate loading.The plate rock experiences initial creep,steady-state creep and accelerated creep under the last stage loading,there is saltatorial creep during the steady-state creep under the confining pressure of 5 MPa and 15 MPa.The rupture form of slate creep mainly occurs along with the bedding plane,there will be tensile failure under low confining pressure, and shear failure will be occured under the high confining pressure.
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