摘要
为了研究深地充填体的断裂特性,分别将经温度为40,60,80,100和120℃热处理后的胶结充填体试件进行三点弯曲试验,利用高速摄像机-加载系统进行裂纹扩展模式全程捕捉,并编写Matlab图像处理程序,对充填体微观结构进行量化分析。研究结果表明:充填体的断裂韧度与纵波波速随热处理温度的升高而减小;当热处理温度从40℃上升到120℃时,充填体断裂韧度降幅达64.72%;基于波速的变化,热损伤因子D可分为3个阶段,即负损伤阶段、加速损伤阶段和稳定损伤阶段;随着热处理温度升高,孔隙率变化趋势与断裂韧度相反;断裂裂纹可分为3个阶段,且随着温度升高,裂纹的整体扩展路径经历了直线→弯曲→直线的过程,并在断裂过程中出现未脱落块体和碎裂状块体的脱落;主裂纹在扩展过程中会衍生出次生裂纹,且主裂纹分叉特征愈加明显。
In order to study the fracture characteristics of the cemented backfill in deep mine,the three-point bending test was carried out for the cemented backfill with heat treatment temperature being 40,60,80,100 and 120℃,respectively.The full range of crack propagation mode was captured by the high speed camera loading system,and the microstructure of the cemented backfill was analyzed quantitatively by Matlab image processing program.The results show that the fracture toughness and longitudinal wave velocity of cemented backfill decrease with the increase of thermal treatment temperature;The fracture toughness of backfill decreases by 64.72%when the heat treatment temperature increases from 40℃to 120℃.The thermal damage factor D is based on the change of the wave velocity,which can be divided into three stages,namely,the negative damage stage,the acceleration injury stage and the stable injury stage.With the increase of heat treatment temperature,the change trend of porosity is opposite to fracture toughness.The crack propagation process is divided into three stages and as the temperature increases,the overall propagation path of the crack has gone through changes from a straight line to a bending curve and then to a straight line,and there are non-shedding blocks and cataclastic blocks during the fracture process.The secondary cracks appear and the bifurcation characteristics of cracks are more obvious during the propagation of the main crack.
作者
徐文彬
曹培旺
程世康
XU Wenbin;CAO Peiwang;CHENG Shikang(College of Resources&Safety Engineering,China University of Mining&Technology,Beijing 100083,China;Key Laboratory of Ministry of Education of China for Efficient Mining and safety of Metal Mines,University of Science and Technology Beijing,Beijing 100083,China)
出处
《中南大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2018年第10期2508-2518,共11页
Journal of Central South University:Science and Technology
基金
国家重点研发项目(2018YFC0808403)
国家自然科学基金资助项目(51504256)~~
关键词
深地采矿
温度
胶结充填体
三点弯曲
裂纹扩展
mining in deep mine
temperature
cemented backfill
three-point bending
crack propagation
