均质度对层理页岩破坏过程声发射影响的数值模拟

Numerical simulation of influence of homogeneous degree on layer shale acoustic emission

采用真实破裂过程分析软件RFPA^(2D)(realistic failure process analysis),结合所取江西页岩岩芯的室内强度、泊松比、弹性模量等实验结果,对不同均质度的不同方向层理面页岩在单轴压缩破坏下的过程及其声发射特性进行了数值模拟。研究表明:页岩层理面方向和均质度对其抗压强度、破坏模式和声发射特性有显著影响。垂直于层理面加载时的抗压强度大于平行于层理面加载时的抗压强度,而其声发射累计数小于平行于层理面加载的声发射累计数。加载方向与层理面垂直时,层理弱面发生剪切破坏,而基质体发生劈裂破坏。加载方向与层理面平行时,主要发生沿层理弱面的竖向劈裂。随着均质度增大,模型峰值应力增大,声发射计数减少,声发射信号出现时间延迟,持续时间变短。声发射的集中带与基元破坏形成的宏观裂纹的位置一致。

Numerical simulation on layer shale in Jiangxi with different degrees of homogeneity and different beddings plane in uniaxial compression tests was studied by the usage of the Realistic Failure Process Analysis software-RFPA2D,and the combination with the experimental result of material parameters,such as strength,Poisson＆#39;＆#39;s ratio and elastic modulus of shale,etc.Study showed that the remarkable effect of homogeneous degree and beddings on compressive strength,failure mode and acoustic emission characteristics of layer shale.Compressive strength when loading perpendicularly to the bedding plane was greater than that when loading parallelly to the bedding plane,while the AE cumulative number was smaller than that of parallel beddings plane load.The failure modes were shear failure along the weak beddings and split failure across the matrix of shale when loading perpendicularly to the bedding plane.That loading direction was parallel to the bedding plane leads to split failure along weak bedding planes.The higher homogeneous degree,the greater peak strength of layer shale samples,and the less total number of AE,in the meantime,a time delay of acoustic emission signals happens while duration time shortens.Acoustic emission bands were located at the similar positions of macroscopic crack due to elements failure.