横观各向同性板岩三轴力学特性及其本构模型  

Triaxial mechanical properties and constitutive model of transversely isotropic slate

作　　者：陈晔磊 李地元[2] 王立川[3,4] 李化云 张鹏飞[2] 吴剑 CHEN Yelei;LI Diyuan;WANG Lichuan;LI Huayun;ZHANG Pengfei;WU Jian(School of Architecture and Civil Engineering,Xihua University,Chengdu 610039,China;School of Resources and Safety Engineering,Central South University,Changsha 410083,China;School of Civil Engineering,Central South University,Changsha 410075,China;China Railway 18th Bureau Group Co.,Ltd.,Tianjin 300222,China;China Railway Southwest Research Institute Co.,Ltd.,Chengdu 611731,China)

机构地区：[1]西华大学建筑与土木工程学院,四川成都610039 [2]中南大学资源与安全工程学院,湖南长沙410083 [3]中南大学土木工程学院,湖南长沙410075 [4]中铁十八局集团有限公司,天津300222 [5]中铁西南科学研究院有限公司,成都611731

出　　处：《铁道科学与工程学报》2023年第2期661-670,共10页Journal of Railway Science and Engineering

基　　金：国家自然科学基金高铁联合基金重点资助项目(U1934211)。

摘　　要：板岩属于典型的横观各向同性材料,其物理力学特性具有明显的方向性。对5种不同层理夹角板岩试样进行2组围压(5 MPa和10 MPa)下的三轴试验,试验结果表明:三轴压缩下不同层理角度板岩的峰值强度、残余强度均随围压的增大而增大,但试验范围内的围压对其径向变形的影响有限,岩石试样弹性阶段的轴向应变增大了17%,径向应变增大了6%;岩石三轴峰值强度、残余强度与层理夹角呈非线性关系,水平层理夹角试样的峰值强度最大,45°层理夹角试样的峰值强度最小,60°层理夹角试样的残余强度最小。板岩最小主应力与岩体层理面的夹角会因开挖后的应力重分布而发生改变,在考虑其力学特性和层理夹角关系的基础上,建立了板岩横观各向同性弹塑性本构模型,通过整体坐标系中的广义胡克定律描述岩石应力-应变关系的弹性部分,计算得到整体坐标系中的弹性刚度矩阵;采用改进后的Mohr-Coulomb屈服准则、非关联流动法则和应变硬化准则描述其塑性部分。本构模型所需的材料参数(如弹性参数,塑性参数)通过常规三轴试验获得,采用FORTRAN语言对UMAT子程序进行二次开发,在ABAQUS中实现了板岩弹塑性本构模型的构建,并将理论模型所得结果与三轴试验结果进行对比,发现所构建的横观各向同性板岩弹塑性本构模型是合理的。The slate is a typical transversely isotropic material, and its physical and mechanical properties have obvious directivity. In this paper, a series of triaxial compression tests were carried out on the slate specimens with five groups of bedding angles under two confining pressure levels(5 MPa and 10 MPa). The testing results indicated that the peak and residual strength values increase with increasing confining pressure, but the confining pressure has less effect on the radial strain of the specimens under the current confining pressure range studied.The axial strain and radial strain values increase by 17% and 6% during the elastic stage, respectively. The triaxial strength of the slate has nonlinear relationship with its bedding angle. The maximum peak strength occurs at the horizontal bedding angle of the specimens, and the minimum peak strength occurs at the bedding angle of 45° and the minimum residual strength occurs at the bedding angle of 60°. The angles between minimum principal stress of slate and bedding plane of rock mass change due to stress redistribution after excavation. Based on the relationship between mechanical properties of slate and bedding angle, the elastoplastic constitutive model of slate was established. In the global coordinate system, the elastic part of the stress-strain relationship was described by the generalized Hooke’s law, and the elastic stiffness matrix was calculated. While considering the effect of bedding angle on rock strength, the plastic part was obtained based on Mohr-Coulomb criterion, nonassociated flow rule and strain hardening criterion. The parameters(e. g., elastic and plastic parameters) in the elastoplastic constitutive model can be obtained from the conventional triaxial tests. Through the secondary development of UMAT subroutine by FORTRAN language and implementation of the elastoplastic constitutive model of slate, the constitutive model of slate was numerically established in ABAQUS. The results of theoretical model were compared with those of triaxia

关 键 词：横观各向同性 板岩 非关联流动法则 本构模型 数值实现 

分 类 号：TU45[建筑科学—岩土工程]