岩石试样脆塑性破裂全过程数值试验研究  

Numerical Experiment on the Whole Process of Brittle and Plastic Fracture of Rock Samples

作　　者：姜波[1] 汤雷[2] 赵新铭[1] 石鑫炜 李国栋 JIANG Bo;TANG Lei;ZHAO Xinming;SHI Xinwei;LI Guodong(Department of Civil and Airport Engineering,Nanjing University of Aeronautics and Astronautics,Nanjing,Jiangsu 210016,China;Materials&Structural Engineering Department,Nanjing Hydraulic Research Institute,Nanjing,Jiangsu 210024,China;STECOL CORPORATION,Tianjin 300384,China)

机构地区：[1]南京航空航天大学土木与机场工程系,江苏南京210016 [2]南京水利科学研究院材料结构研究所,江苏南京210024 [3]中国电建市政建设集团有限公司,天津300384

出　　处：《矿业研究与开发》2021年第1期81-87,共7页Mining Research and Development

基　　金：国家自然科学基金资助项目(51739008,51527811);中国电力建设股份有限公司科技项目(KJ-2019-032)。

摘　　要：为了探究岩石试样形状与其塑性性能的关系,在PFC2D中建立了中颗粒大理岩和三峡花岗岩的数值模型,进行不同高宽比数值试样的单轴压缩试验。比较应力-应变曲线,发现随着高宽比的减小,两种岩性的试样均出现了由脆性破坏向延性破坏发展的趋势。同时声发射模式由主震-后震型向前震-主震-后震和群震型转化。另外,利用两种常见的脆性评价方法,计算了不同高宽比试样的脆性指数。随着高宽比的变化,岩石的脆、塑性性能体现出巨大的差异性,试样脆性指数与其高宽比呈正相关关系。根据应力-应变曲线、声发射曲线、裂缝扩展形式和脆性指数的变化情况,较好地阐述了岩石试样随高宽比的改变所呈现出脆-延-塑性转化的特性。岩石的脆、塑性破坏的本质是因为其裂缝扩展方式的显著不同,岩石的脆性失稳是由一条或者较少的主裂缝贯穿引起,而塑性失稳往往会产生较多的主裂缝。In order to explore the relationship between the rock samples’shape and their plastic properties,numerical models of medium-particle marble and the Three Gorges granite were established in PFC2 D,and the uniaxial compression test of numerical specimens with different aspect ratios were carried out.Comparing the stress-strain curves,it could be found that as the aspect ratio decreases,both specimens show a trend from brittle failure to ductile failure.At the same time,the acoustic emission mode is transformed from the main-post shock type to front-main-post shock and group shock type.In addition,the brittleness index of specimens with different aspect ratios was calculated by two common brittleness evaluation methods.With the change of aspect ratio,the brittle and plastic properties of rock show great difference,and the brittleness index of the specimen is positively correlated with its aspect ratio.According to the changes of stress-strain curve,acoustic emission curve,fracture propagation and brittleness index,the characteristics of brittle-ductile-plastic transformation of rock specimens with the change of aspect ratio are well described.The essence of brittle and plastic fracture of rock lies in different ways of fracture propagation.Brittle instability of rock is caused by one or a few of main fractures penetrating through,while plastic instability always produces lots of main fractures.

关 键 词：单轴压缩 PFC 高宽比 脆性评价 裂缝扩展 

分 类 号：TD315[矿业工程—矿井建设] TU45[建筑科学—岩土工程]