基于煤岩冲击与大变形特征的统一脆延性指标研究  

Study on unified brittle-ductility index based on burst tendency and large deformation of coal-rock

作　　者：李震[1,2] 史文豪 高鑫 张呈祥 崔恒 徐玉龙 LI Zhen;SHI Wenhao;GAO Xin;ZHANG Chengxiang;CUI Heng;XU Yulong(School of Civil Engineering,Henan Polytechnic University,Jiaozuo454003,China;Collaborative Innovation Center of Coal Work Safety and Clean High Efficiency Utilization,Jiaozuo454003,China;Shandong Energy Group Co.,Ltd.,Jinan250014,China;China Railway Siyuan Survey and Design Group Co.,Ltd.,Wuhan430063,China)

机构地区：[1]河南理工大学土木工程学院,河南焦作454003 [2]煤炭安全生产与清洁高效利用省部共建协同创新中心,河南焦作454003 [3]山东能源集团有限公司,山东济南250014 [4]中铁第四勘察设计院集团有限公司,湖北武汉430063

出　　处：《煤炭科学技术》2022年第10期19-27,共9页Coal Science and Technology

基　　金：河南理工大学杰出青年基金资助项目(J2021-2);国家自然科学基金资助项目(51704097)。

摘　　要：冲击倾向性和延性分别是硬脆性煤岩和软岩的本质属性,开展岩性表征和脆延转换研究对深部工程安全采掘具有重要意义。为提出一种综合表达脆性破坏和软岩大变形特征的评价指标,总结了现有的冲击倾向性指标,基于全应力-应变曲线建立了统一脆延性指标(B_(u)),并结合试验数据进行了分析与探讨。结果表明:统一脆延性指标反映了煤岩脆/延性变形特征与破坏程度,统一脆延性指标B_(u)<0对应峰后应变硬化,B_(u)=0对应理想弹塑性变形,B_(u)>0对应峰后应变软化,B_(u)趋于正无穷对应理想脆性破坏;基于统一脆延性指标将冲击倾向性划分为3个等级,B_(u)<4.0时为无冲击倾向性,B_(u)介于4.0~28.0时为弱冲击倾向性,B_(u)>28.0时为强冲击倾向性。统一脆延性指标为无量纲指标,可以反映单轴条件和不同应力水平下脆性破坏特征,以及软弱或高应力水平下煤岩峰后应变硬化特征,尤其突出了单轴条件下不同煤岩脆性跌落的差别,对测试峰后急剧跌落煤岩的冲击倾向性有非常好的适用性。Burst tendency and ductility are the essential attributes of hard and brittle rocks respectively.It is of great significance to carry out lithology characterization and brittle-ductile transformation research for safe mining in deep engineering.In order to propose a comprehensive evaluation index to express the burst tendency and ductility characteristics,the existing burst tendency indices were summarized.A unified brittle-ductile index(B_(u))was established based on the complete stress-strain curve.The new index was analyzed and discussed with tests.The results show that the unified brittle-ductility index reflects the deformation characteristics and damage degree of rocks.B_(u) less than 0 corresponds to the post-peak strain-hardening.B_(u) equal to 0 corresponds to the ideal elastic-plastic deformation.B_(u) greater than 0 expresses the post-peakstrain-softening.B_(u) approaching infinite corresponds to the ideal brittle failure.Secondly,based on unified brittleness and ductility index,the burst tendency is divided into three levels.When B_(u) is less than 4.0,there is no impact tendency,when B_(u) is between 4.0 and 28.0,there is weak impact tendency,and when B_(u) is more than 28.0,it indicates a strong impact tendency.At last,the unified brittle-ductile index is a dimensionless index,which can reflect the brittle failure characteristics under uniaxial conditions and different stress levels,as well as the evaluation of post-peak strain-hardening characteristics of soft rocks or rocks under weak or high stress levels,especially highlighting the brittleness drop of different coal rocks under uniaxial conditions.The difference is very suitable for the impact tendency of coal rock falling sharply after the test peak.

关 键 词：冲击倾向性 深部工程 全应力-应变曲线 脆延转换 脆性破坏 

分 类 号：TD324[矿业工程—矿井建设]