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采选技术与矿山管理

不同应力条件下硬岩强度与破裂特性试验研究

  • 杜坤 , 1, 2 ,
  • 杨颂歌 1 ,
  • 苏睿 1 ,
  • 杨成志 1 ,
  • 王少锋 , 1
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  • 1. 中南大学资源与安全工程学院,湖南 长沙 410083
  • 2. 中南大学高等研究中心,湖南 长沙 410083
王少锋(1989-),男,河南洛阳人,教授,硕士生导师,从事深部硬岩破碎与岩体灾害防控方面的研究工作。

杜坤(1985-),男,山东泰安人,研究员,博士生导师,从事深部矿山开采及岩石力学方面的研究工作。

收稿日期: 2021-01-01

  修回日期: 2021-02-24

  网络出版日期: 2021-07-14

基金资助

国家自然科学基金面上项目“深部硬岩矿山工程围岩非常规破裂演化与阻断机制”(51774326)

国家自然科学基金青年基金项目“高应力硬岩真三轴卸载下扰动破裂特性与机制研究”(51504287)

Experimental Study on Strength and Fracture Characteristics of Hard Rock Under Different Stress Conditions

  • Kun DU , 1, 2 ,
  • Songge YANG 1 ,
  • Rui SU 1 ,
  • Chengzhi YANG 1 ,
  • Shaofeng WANG , 1
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  • 1. School of Resource and Safety Engineering,Central South University,Changsha 410083,Hunan,China
  • 2. Advanced Research Center,Central South University,Changsha 410083,Hunan,China

Received date: 2021-01-01

  Revised date: 2021-02-24

  Online published: 2021-07-14

本文亮点

深部工程围岩内的岩石可能处于一维、二维和三维应力状态下,分别对应室内单轴压缩、双轴压缩和真三轴压缩试验中岩样的应力状态。通过开展单轴、双轴和真三轴压缩试验,系统研究了不同应力状态和水平下岩石非常规破坏的发生机制。不同高宽比和宽厚比岩样的单轴压缩试验结果表明:随着岩样厚度的增加,单轴抗压强度单调增加;随着岩样高度的增加,单轴抗压强度往往先增加后减小,且矮薄岩样更容易发生岩爆和板裂等非常规破坏。双轴或真三轴压缩试验中岩样的抗压强度均表现出明显的中间主应力效应。在相同最小主应力下,随着中间主应力的增加,岩样的双轴抗压强度和真三轴抗压强度均呈先增加后减小的变化趋势,双轴抗压强度增长率则呈先减小而后小幅增大的趋势。通过定义强度增量参数ν和中间主应力位置参数λ构建了指数岩石真三轴强度准则。低围压限制、非对称围压限制和短裂纹扩展路径是引起岩石非常规破坏的主要条件。

本文引用格式

杜坤 , 杨颂歌 , 苏睿 , 杨成志 , 王少锋 . 不同应力条件下硬岩强度与破裂特性试验研究[J]. 黄金科学技术, 2021 , 29(3) : 372 -381 . DOI: 10.11872/j.issn.1005-2518.2021.03.012

Highlights

The unconventional failure phenomenon of rocks,such as slabbing and rock burst,occur frequently in deep engineering,which bring huge financial loss and casualties.The occurring mechanism of the un-conventional failure is still unclear,and the stress state and levels of rocks is the main factors inducing unconventional failure.The surrounding rocks of deep engineering is under a one-dimensional,two-dimensional or three-dimensional stress conditions,corresponding to the stress state of the rock specimen in the uniaxial,biaxial or true triaxial compression tests,respectively.In this study,the uniaxial,biaxial or true triaxial compression tests were carried out to reveal the occurring terms of the unconventional failure of rocks.The isolated ore pillars left after room-pillar mining are usually under one-dimensional compressive stress.Through uniaxial compression tests of rock specimens with different height-width ratios and width-thickness ratios,it is found that the strength of rock specimen exhibits obvious characteristics of non-linear changes as the height and width of rock specimen increase.As the thickness increases,the uniaxial compressive strength increases.As the height increases,the uniaxial compressive strength tends to increase first and then decrease.This is mainly related to the slabbing failure of the dwarf and thin rock specimens.Combining the uniaxial compression test of cuboid rock specimens and the reduction of rock mass mechanical parameters,the safety evaluation of the isolated pillars can be conducted.Based on the fact that the surrounding rocks of underground engineering are often under a two-dimensional stress state,and the fact that rocks far away from the boundaries of underground engineering are often under a three-dimensional stress state,the biaxial compression and true triaxial compression tests of cubic rock specimens have been carried out.The rock strength in biaxial or true triaxial test shows obvious intermediate principal stress effect.Under the same minimum principal stress,the biaxial compressive strength and true-triaxial compressive strength of rocks increases first and then decreases with the increase of the intermediate principal stress,and the change rate of biaxial compressive strength decreases firstly and then shows a little increase.An exponential rock strength criterion was constructed by defining the strength increment parameter ν and the intermediate principal stress position parameter λ.It is considered that low confining pressure limitation,asymmetric confining pressure limitation and short crack propagation path are the main terms for unconventional failures of rocks under multi-dimensional stress conditions.

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脚注

http://www.goldsci.ac.cn/article/2021/1005-2518/1005-2518-2021-29-3-372.shtml

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