轴对称单轴压缩岩石材料应变局部化剪切带数值模拟研究

摘要

利用FLAC3D数值软件中的应变硬化一软化本构模型,模拟轴对称单轴压缩条件下岩石试件应变局部化剪切带的形成过程,同时对不同端面效应下长径比效应对应变局部化剪切带的影响进行分析.结果表明,岩石试件的应变局部化剪切带的启动、发展到最终形成是一个渐进的演化过程.端面效应和长径比效应均影响应变局部化剪切带的形状和岩石强度.光滑边界应变局部化剪切带形成于试件上下端面,摩擦边界形成于试件中部区域,且摩擦边界时试件的峰值强度高于光滑边界,峰值强度后的软化阶段陡峭于光滑边界.随着岩石试件长径比的增加,岩石的峰值强度在逐步降低,达到峰值强度所需的时步却呈增加的趋势.这一研究成果有助于加深理解岩石破坏过程.%Using strain hardening-softening constitutive model of FLAC3D numerical software,the formation process of strain localization shear zone was simulated under the axisymmetric uniaxial compression condition for rock specimen,and the influence of length-to-diameter ratio effect on the strain localization shear zone was also analyzed under the effect of different end faces.The results showed that startup,development and the final form of the strain localization shear band is a gradual evolutionary process of the rock specimen.End face effect and length-to-diameter ratio effect affect shape and rock strength of the strain localization shear zone.Strain localization shear zone is formed in the upper and lower end face of the specimen with smooth boundary,while that is formed in the central area of the specimen with friction boundary.At the same time,peak strength and subsequent softening stage of friction boundary are higher than those of smooth boundary.With the increase of length-to-diameter ratio,the peak strength of the rock is reduced gradually,and the required time step is increased to obtain peak intensity.These research results will help deepen the understanding of rock failure process.