摘要
为探究尾砂粒径分布对充填体强度和损伤特性的影响,对超细尾砂(中值粒径D_(50)=10.1μm)、细尾砂(D_(50)=37.1μm)和粗尾砂(D_(50)=121.31μm)充填体开展单轴压缩试验、扫描电镜试验和数字图像相关(digital image correlation,简称DIC)试验,分析其强度特性和微观结构特征,并基于尖点突变理论,采用小波包技术构建充填体损伤识别指标,量化分析充填体损伤特性。研究结果表明:充填体强度和弹性模量随尾砂D_(50)的增大呈先增大后减小的趋势,但随着料浆浓度的升高,尾砂粒径对充填体强度和弹性模量的影响减小;相对超细尾砂和粗尾砂充填体,细尾砂充填体粗、细颗粒结合紧密,孔隙度最低,微观结构致密性最好;定义能量变化率(energy change rate,简称ECR)突变点为试件损伤突变的阈值,用于区分试件稳定损伤阶段和加速损伤阶段,其中,超细尾砂、细尾砂和粗尾砂充填体分别在峰值应力的92.83%、92.31%和72.93%处发生损伤突变;随尾砂D_(50)的增大,充填体破坏模式由剪切破坏向张拉破坏转变,破坏时ECR由20.65%增大为28.25%,损伤破坏程度逐渐加重。研究结果为改良矿山尾砂颗粒级配,进而提高充填体强度奠定了基础。
To explore the influence of tailings particle size distribution on strength and damage characteristics of filling body, uniaxial compression, scanning electron microscopy, and digital image correlation(DIC) tests were carried out on the filling body composed of ultrafine tailings(median particle size D_(50)=10.1 μm), fine tailings(D_(50)=37.1 μm), and coarse tailings(D_(50)= 121.31 μm), and the strength and microstructure characteristics were analyzed. Based on the cusp mutation theory, the damage identification index of the filling body was established using wavelet packet technology, and the damage characteristics of the filling body were quantitatively analyzed. The results reveal that the strength and elastic modulus of the filling body first increase and then decrease with the increase of D_(50), but the influence of tailings particle diameter on the strength and elastic modulus of the filling body is reduced with the increase of slurry concentration. Compared with the ultrafine and coarse tailings filling body, the coarse and fine particles of the fine tailings backfill are more closely combined, and its porosity is the lowest and microstructure compactness is the best. The energy change rate(ECR) mutation point is defined as the threshold of the backfill specimen damage mutation, which is used to distinguish the stable damage stage and the accelerated damage stage of the specimen, and the damage mutations of the ultrafine, fine, and coarse tailings filling body occur when their stresses reach 92.83%, 92.31%, and 72.93% of the corresponding peak stresses. With the increase of D_(50), the failure mode of the backfill changes from shear failure to tensile failure, with the ECR increasing from 20.65% to 28.25%, and the damage degree is gradually aggravated. The research results lay the foundation for improving the particle gradation of mine tailings and enhancing the strength of filling body.
作者
金爱兵
王杰
陈帅军
李海
JIN Ai-bing;WANG Jie;CHEN Shuai-jun;LI Hai(Key Laboratory of Ministry of Education for Eficient Mining and Safety of Metal Mine,University of Science and Technology Beiing,Beiing 100083,China;School of Civil and Resources Engineering,University of Science and Technology Beiing,Beijing 100083,China)
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2022年第11期3083-3093,共11页
Rock and Soil Mechanics
基金
国家自然科学基金资助项目(No.51804018,No.52174106)。
关键词
尾砂粒径
数字图像相关法
小波包能谱分析
微损伤识别指标
尖点突变理论
particle size of tailings
digital image correlation(DIC)
wavelet packet energy spectrum analysis
micro damage identification index
cusp mutation theory
