摘要
我国西南山区水利水电工程中玄武岩断续柱状节理赋存环境复杂,室内力学特性试验是探究柱状节理玄武岩失效模式与劣化机制的有益手段,借助3D打印技术、MTS单轴压缩试验与微距相机拍照,深化研究了柱状节理玄武岩试样的变形失效模式,讨论了柱状节理玄武岩试样各向异性效应并对其进行了量化分析研究。研究结果表明:(1)受柱体倾斜角度的影响,柱状节理玄武岩试样的破坏形态差异性较为显著,可以总结出3类典型失效模式,沿柱状节理网络的轴向劈裂失效模式、沿柱状节理面的剪切-滑移失效模式以及贯穿节理网络的张拉-剪切失效模式,失效模式符合坝址区地下洞室开挖过程中实际揭露的柱状节理玄武岩破坏情况;(2)柱状节理玄武岩试样峰值强度与变形模量随柱体倾角的变化曲线呈现“肩型”各向异性;(3)引入强度和模量各向异性比概念,给定了不同倾斜角度工况下柱状节理玄武岩试样的各向异性等级。该研究结果对实际工程岩体的变形失效模式与各向异性特征分析具有一定的参考价值。
The occurrence environment of intermittent columnar jointed basalts in water conservancy and hydropower projects in the mountainous regions of southwest China is complex.Indoor mechanical testing is a valuable method for investigating the failure pattern and degradation mechanism of columnar jointed basalts.With the help of 3D printing technology,MTS uniaxial compression test and macro camera photography,the failure pattern of columnar jointed basalts is extensively investigated,and the anisotropic effect of columnar jointed basalts is discussed and quantitatively analyzed.The research results show that the failure pattern of simulated columnar jointed basalt samples varies significantly due to the influence of the inclination angle of the cylinder.In line with the failure phenomena of columnar jointed basalts that are exposed in underground excavation engineering of dam area,three typical failure patterns of physical models of columnar jointed rock masses are presented.Axial splitting failure along the columnar joint network,shear-slide failure along the columnar joint surface,tensile-shear failure through the columnar joint network are observed.The variation curves of the peak strength and deformation modulus of simulated columnar jointed basalt samples with the change of column inclination angle present the“shoulder shape”anisotropy.The concept of strength and modulus anisotropy ratio is introduced,and the anisotropy grade of simulated columnar jointed basalt samples under different inclined angles is given.The research results have certain reference value for the analysis of deformation and failure pattern and anisotropic characteristics of actual engineering rock masses.
作者
孔洋
阮怀宁
汪璋淳
KONG Yang;RUAN Huai-ning;WANG Zhang-chun(Department of Geotechnical Engineering,Nanjing Hydraulic Research Institute,Nanjing,Jiangsu 210024,China;Institute of Geotechnical Research,Hohai University,Nanjing,Jiangsu 210029,China)
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2024年第S01期259-266,共8页
Rock and Soil Mechanics
基金
国家自然科学基金长江水科学研究联合基金(No.U2240221)
国家自然科学基金(No.41831278)
关键词
玄武岩
失效模式
变形破坏
各向异性
柱状节理
basalt
failure pattern
deformation and failure
anisotropy
columnar joint
