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  • CN 62-1112/TF 
  • ISSN 1005-2518 
  • 创刊于1988年
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采选技术与矿山管理

单轴压缩试验中减弱端部效应新型方法研究

  • 贾敬锎 ,
  • 黄滚 ,
  • 汪龙 ,
  • 成墙 ,
  • 甄利兵
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  • 1.重庆大学煤矿灾害动力学与控制国家重点实验室,重庆 400044
    2.重庆大学资源与安全学院,重庆 400044
贾敬锎(1996-),男,河北石家庄人,硕士研究生,从事岩石力学与工程方面的研究工作。cqujjk@163.com

收稿日期: 2020-12-23

  修回日期: 2021-03-04

  网络出版日期: 2021-07-14

Study on a New Method of Weakening End Effect in Uniaxial Compression Test

  • Jingkai JIA ,
  • Gun HUANG ,
  • Long WANG ,
  • Qiang CHENG ,
  • Libing ZHEN
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  • 1.State Key Laboratory of Coal Mine Disaster Dynamics and Control,Chongqing University,Chongqing 400044,China
    2.School of Resources and Safety Engineering,Chongqing University,Chongqing 400044,China

Received date: 2020-12-23

  Revised date: 2021-03-04

  Online published: 2021-07-14

摘要

为了减弱端部效应对单轴抗压强度测量的影响,提出一种新型的单轴压缩试验方法。该方法采用与试件材质相同的岩石作为垫块进行单轴压缩试验,设置了(25+50+25)mm和(20+60+20)mm 2种试件高度组合进行试验,并与高度为50 mm、60 mm的单一试件的试验结果进行对比。结果表明:该新型试验方法可以降低单轴压缩试验中端部效应对测量岩石单轴抗压强度的影响,并得到更为均匀的径向应变;(25+50+25)mm和(20+60+20)mm组合试件相比高度为50 mm和60 mm的单一试件,单轴抗压强度分别降低了38.41%和39.69%,相比标准试件,单轴抗压强度也有所降低。数值模拟结果表明:无论有无端部摩擦,组合试件的单轴抗压强度均与理想状态下模拟所得的岩石试件的单轴抗压强度值接近;无端部摩擦时单个试件与组合试件具有均匀的径向应变;有端部摩擦时组合试件的径向应变较为均匀。数值模拟结果证明了该新型试验方法减弱了端部效应,但并未完全消除。

本文引用格式

贾敬锎 , 黄滚 , 汪龙 , 成墙 , 甄利兵 . 单轴压缩试验中减弱端部效应新型方法研究[J]. 黄金科学技术, 2021 , 29(3) : 382 -391 . DOI: 10.11872/j.issn.1005-2518.2021.03.003

Abstract

As a difficult point in rock mechanics,end effect has been widely concerned by scholars.The phenomenon of end effect is caused by the friction between the indenter of testing machine and rock specimen in the process of compression,which usually causes the measured compressive strength of rock increased.However,the more intuitive performance of end effect is that the radial strain of rock is larger in the middle and smaller at both ends.According to Saint-Venant’s principle,when the height diameter ratio is greater than 2.0,the influence of the end effect can be ignored,but only the influence of the end effect on the measured uniaxial compressive strength can be ignored,which doesn’t form uniform stress in the specimen.Therefore,the method of weakening the end effect should be further studied.By summarizing the research of domestic and foreign scholars,it is found that there are two main methods to reduce the end effect,they are reducing the end friction and controlling the end deformation.The first method is to add friction reducing agent between the indenter of the testing machine and the end of the rock specimen,but it can’t completely eliminate the end effect.The second method is to use the metal specimen with the same mechanical parameters as the rock specimen as the cushion block,but it is too difficult to find this kind of metal material.Based on the second idea,to reduce the influence of end effect in the measurement of uniaxial compressive strength,a new uniaxial compression test method was proposed.In this method,uniaxial compression test was carried out using the rocks with the same material as the specimen as the cushion block.Two combination forms of (25+50+25)mm and (20+60+20)mm are set for the experiment,and the experimental results are compared with those specimens with the height of 50 mm and 60 mm.The results show that the new experimental method can reduce the influence of end effect on the measurement of uniaxial compressive strength of rock and obtain more uniform radial strain.Compared with the specimens with the height of 50 mm and 60 mm,the uniaxial compressive strength of the specimens with the height of (25+50+25)mm and (20+60+20)mm is reduced by 38.41% and 39.69% respectively,ad-ditionally,the strength is also decreased comparing with the standard specimen.Numerical simulation results show that the uniaxial compressive strength of the combined specimen with or without end friction is close to the uniaxial compressive strength of the standard specimen in ideal state.All of the specimens have uniform radial strain without end friction.The radial strain of the combined specimen is relatively uniform when there is end effect.Numerical simulation results prove that the new experimental method reduces the end effect,but it can’t completely eliminate the end effect.

参考文献

null Akai K,Mori H,1967.Study on the failure mechanism of a sandstone under combined compressive stresses[J].Transaction of Japan Society of Civil Engineering,147:11-24.
null Al-Chalabi M,Huang C L,1974.Stress distribution within circular cylinders in compression[J].International Journal of Rock Mechanics and Mining Science&Geomechanics Abstract,11(2):45-56.
null Bai Shiwei,Lin Shisheng,Zhu Weishen,1982.Uniformity of stress distributions in rock cylinder specimen under uniaxial compression[J].Chinese Journal of Geotechnical Engineering,4(4):193-203.
null Brady B T,1971.Effects of inserts on the elastic behavior of cylindrical materials loaded between rough end-plates[J].International Journal of Rock Mechanics and Mining Science,8:357-369.
null Fan Pengxian,Wang Jiabo,Liu Jiagui,al et,2019.The influence of end condition on the test strength of red sandstone samples[J].Journal of Basic Science and Engineering,29(2):426-437.
null Geng Yongming,2019.Study on Best Aspect Ratio of Standard Test Specimens for Rock Material During Deformation and Failure[D].Lanzhou:Lanzhou University.
null Guo Baohua,2009.Numerical analysis of size scale,inner hole and end restraint effects of rock samples[J].Chinese Journal of Rock Mechanics and Engineering,28(Supp.2):3391-3401.
null Hou Hongtao,Zhang Sheng,Wu Guofeng,2015.Influence of stress distribution regulation of sample ends on uniaxial compression with pad[J].Journal of Anhui University of Science and Technology (Natural Science),35(3):59-62.
null Liang Zhengzhao,2005.Three-dimensional Failure Process Analysis of Rock and Associated Numerical Tests[D].Shenyang:Northeastern University.
null Liang Zhengzhao,Tang Chun’an,Zhang Juanxia,al et,2007.Three-dimensional damage model for failure process of rocks and associated numerical simulation of geometry effect[J].Rock and Soil Mechanics,(4):699-704.
null Liang Zhengzhao,Wu Xiankai,Tang Shibin,al et,2018.Numerical simulation on end effect of rock specimens based on the anisotropic interface element model[J].Journal of Basic Science and Engineering,26(3):526-537.
null Liu Jiguo,Zeng Yawu,2005.Numerical simulation of the end frictional effect of rock specimens[J].Journal of Engineering Geology,13(2):297-251.
null Pan Pengzhi,Zhou Hui,Feng Xiating,2008.Research on effect of loading conditions on failure processes of rocks with different sizes under uniaxial compression[J].Chinese Journal of Rock Mechanics and Engineering,(Supp.2):3636-3642.
null Peng S D,1971.Stresses within elastic circular cylinders loaded uniaxially and triaxially[J].International Journal of Rock Mechanics and Mining Science,8(5):339-432.
null Szczepanik Z,Milne D,Hawkes C,2007.The confining effect of end roughness on unconfined compressive strength [C]//The Proceedings of the 1st Canada-US Rock Mechanics Symposium-Rock Mechanics Meeting Society’s Challenges and Demands. London:Taylor&Francis Ltd:793-797.
null Tang C,Tham L,Lee P,al et,2000.Numerical studies of the influence of microstructure on rock failure in uniaxial compression — Part II:Constraint,slenderness and size effect[J].International Journal of Rock Mechanics and Mining Sciences,37(4):571-583.
null Wang Xuebin,Pan Yishan,Sheng Qian,al et,2002.Numerical simulation on strain localization of end constraint of rock specimen[J].Journal of Engineering Geology,10(3):233-236.
null You Mingqing,2016.End effects on strengths of rocks under true triaxial compression[J].Chinese Journal of Rock Mechanics and Engineering,35(Supp.1):2603-2607.
null You Mingqing,2018.Study on ends effect in conventional triaxial compression test and the strengths property of granites[J].Chinese Journal of Rock Mechanics and Engineering,37(Supp.1):3160-3168.
null You Mingqing,Hua Anzeng,1997.The size effect of uniaxial compression of rock specimen and support capacity of ore pillar[J].Journal of China Coal Society,(1):39-43.
null You Mingqing,Su Chengdong,2004.Effect of length of fine and coarse crystal marble specimens on uniaxial compression tests[J].Chinese Journal of Rock Mechanics and Engineering,(22):3754-3760.
null You Mingqing,Zou Youfeng,2000.Discussion on heterogeneity of rock material and size effect on specimen strength[J].Chinese Journal of Rock Mechanics and Engineering,(3):391-395.
null Yu Jian,Wang Yanyan,Wang Qing,al et,2019.Study of triaxial mechanical test based on MSV method for reducing end friction effect[J].Journal of China Three Gorges University(Natural Sciences),41(5):59-64.
null 白世伟,林世胜,朱维申,1982.单轴压缩圆柱状岩石试件应力分布均匀性的研究[J].岩土工程学报,4(4):193-203.
null 范鹏贤,王贾博,刘家贵,等,2019.端部条件对红砂岩试件测试强度影响的试验研究[J].应用基础与工程科学学报,29(2):426-437.
null 耿永明,2019.岩石材料标准试件变形破坏的最佳长径比研究[D].兰州:兰州大学.
null 郭保华,2009.岩样尺度、孔道及端部摩擦效应的数值分析[J].岩石力学与工程学报,28(增2):3391-3401.
null 侯宏涛,张盛,吴国峰,2015.垫块对单轴压缩试样端部应力分布规律的影响[J].安徽理工大学学报(自然科学版),35(3):59-62.
null 梁正召,2005.三维条件下的岩石破裂过程分析及其数值实验方法研究[D].沈阳:东北大学.
null 梁正召,唐春安,张娟霞,等,2007.岩石三维破坏数值模型及形状效应的模拟研究[J].岩土力学,(4):699-704.
null 梁正召,吴宪锴,唐世斌,等,2018.基于各向异性界面单元的岩石端部效应数值模拟[J].应用基础与工程科学学报,26(3):526-537.
null 刘继国,曾亚武,2005.岩石试件端面摩擦效应数值模拟研究[J].工程地质学报,13(2):297-251.
null 潘鹏志,周辉,冯夏庭,2008.加载条件对不同尺寸岩石单轴压缩破裂过程的影响研究[J].岩石力学与工程学报,(增2):3636-3642.
null 王学滨,潘一山,盛谦,等.2002.岩石试件端面效应的变形局部化数值模拟研究[J].工程地质学报,10(3):233-236.
null 尤明庆,2016.端部效应对岩石真三轴压缩强度的影响[J].岩石力学与工程学报,35(增1):2603-2607.
null 尤明庆,2018.常规三轴压缩的端部效应及花岗岩强度的研究[J].岩石力学与工程学报,37(增1):3160-3168.
null 尤明庆,华安增,1997.岩样单轴压缩的尺度效应和矿柱支承性能[J].煤炭学报,(1):39-43.
null 尤明庆,苏承东,2004.大理岩试样的长度对单轴压缩试验的影响[J].岩石力学与工程学报,(22):3754-3760.
null 尤明庆,邹友峰,2000.关于岩石非均质性与强度尺寸效应的讨论[J].岩石力学与工程学报,(3):391-395.
null 余健,王岩岩,王晴,等,2019.基于MSV方法削弱端部摩擦效应的三轴力学试验研究[J].三峡大学学报(自然科学版),41(5):59-64.
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