层状片麻岩力学性质与变形场演化特征研究  

Mechanical properties and deformation field evolution of layered gneiss

作　　者：王晓雷 蒋鹏程 闫顺玺 詹思博 皇甫润 WANG Xiaolei;JIANG Pengcheng;YAN Shunxi;ZHAN Sibo;HUANGFU Run(College of Mining Engineering,North China University of Science and Technology,Tangshan,Hebei 063210,China)

机构地区：[1]华北理工大学矿业工程学院,河北唐山063210

出　　处：《采矿与安全工程学报》2020年第6期1255-1262,共8页Journal of Mining & Safety Engineering

基　　金：国家自然科学基金重大项目(51134005)。

摘　　要：为探究不同层理倾角片麻岩的破裂失稳与变形场演化特征,采用TAW-3000型刚性伺服试验机和VIC-3D全场应变数字散斑测量系统,通过对0°,30°,45°,60°,90°5种层理倾角片麻岩进行单轴压缩试验,揭示不同层理倾角片麻岩力学性质和应变场演化特征。研究表明:随着层理倾角的增加,片麻岩的破坏模式由贯穿层理的张拉和沿层理面的剪切混合破坏向沿层理面的剪切滑移破坏转变,倾角为90°时为沿层理面的张拉劈裂破坏,并且一般有多个破裂面;单轴抗压强度和弹性模量随倾角的增加表现出先降后升趋势,大致呈“V”形,60°时最低,90°时最高;60°时片麻岩单轴抗压强度的层理结构效应最明显;相同倾角时,随着荷载的增加,应变场由均匀分布向着应变集中带分布转变。相同荷载时,倾角越大的试件能越早观测到应变集中带;应变均方差曲线在试件微裂纹压密及弹性阶段较小且变化平缓,在塑性和破坏阶段陡升。不同倾角试件在不同荷载阶段的应变均方差上升幅度不同,峰前荷载75%σ至峰后荷载50%σ是岩石变形显著阶段;分别定义应变均方差曲线第一次出现转折点和斜率陡增点为一、二级预警信号,其中时间预警整体优于应力预警。研究结果可为实际工程岩体的稳定性控制及防治提供理论依据。In order to explore the fracture instability and deformation field evolution characteristics of gneiss with different bedding dip angles,the TAW-3000 rigid servo testing machine and VIC-3D strain digital speckle measuring system have been used to reveal the mechanical properties and strain field evolution characteristics of gneiss with different bedding dip angles through uniaxial compression tests on gneiss of bedding dip angles of 0°,30°,45°,60°and 90°.The results have shown that with the increase of bedding angle,the failure mode of gneiss changes from tensile failure through bedding and shear mixed failure along bedding plane to shear slip failure along bedding plane.When the stratification angle reaches 90°,the failure mode is tension splitting failure along the stratification surface,and there are usually multiple fractures.The uniaxial compressive strength and elastic modulus shows a trend of first decreasing and then rising with the increase of bedding angle,roughly showing a“V”shape,ranging from the lowest at 60°to the highest at 90°.The effect of bedding structure on the uniaxial compressive strength of gneiss is the most obvious at 60°.At the same dip angle,with the increase of load,the strain field changes from uniform distribution to the distribution of strain concentration zone.Under the same load,the larger the dip angle is,the earlier the strain concentration zone can be observed.The strain mean square deviation curve is small and gentle at the compaction and elastic stage of the microcrack,but rises steeply at the plasticity and failure stage.At different loading stages,the mean square deviation of strain increases differently at different angles.The deformation from pre-peak load of 75%σto post-peak load of 50%σis significant.The first turning point and the steep increase point of the strain mean square deviation curve are defined as the first and the second warning signals respectively,and time early warning is better than stress early warning.The research results can provide the

关 键 词：层理效应 力学性质 数字散斑 预警特征点 

分 类 号：TU443[建筑科学—岩土工程]