摘要
为研究早期受载对矸石胶结充填体后期力学特性的影响,将养护7 d的试样进行4种应力水平加载,并持载28 d后,卸载进行单轴压缩试验,监测持载过程中充填体中超声波波速变化及单轴压缩过程中声发射响应特征,采用扫描电镜观测试样微观形貌。结果表明:早期受载对充填体力学特性影响显著,当早期承受应力水平小于80%时,荷载对矸石胶结充填体抗压强度和弹性模量均具有明显的强化效应,随着早期应力水平的增大,横向应变及泊松比整体呈指数型增长趋势,试样破坏形式由剪切破坏逐渐转变为劈裂破坏。持载过程中超声波波速呈明显的阶段性特征,早期承受高应力水平的充填体在单轴压缩过程中声发射活跃程度下降。早期荷载作用促进水泥水化反应,有助于充填体强度的提高。根据试验结果建立早期受载矸石胶结充填体在单轴压缩过程中的损伤演化模型,可以为充填体在结构充填中的设计提供依据。
In order to study the effect of the early load on the later mechanical properties of cemented gangue backfill(CGB),the specimens cured for 7 days were loaded at 4 stress levels,and after 28 days of continuously loading,unloaded and used for carrying out uniaxial compression test.The ultrasonic wave velocity changes in the CGB during the continuous loading process and the acoustic emission response characteristics during the uniaxial compression process were monitored,and the microscopic morphology of the specimens was observed using a scanning electron microscope.The results show that the early load has a great influence on the mechanical properties of the CGB.When the early stress level is less than 80%,the load has a significant strengthening effect on the compressive strength and the elastic modulus of the CGB.With increasing the early stress level,the transverse strain and the Poisson’s ratio increase exponentially,and the specimen failure form gradually changes from shear failure to split failure.The ultrasonic wave velocity shows obvious multistage characteristics during the continuous load process,and the acoustic emission activity of the CGB subjected to high stress levels decreases.Early load promotes cement hydration reaction and contributes to the improvement of the strength.According to the test results,a damage evolution model of the early loaded CGB was established under uniaxial compression,which can provide a basis for the design of the backfill in the structural filling.
作者
冯国瑞
解文硕
郭育霞
郭军
冉洪宇
赵永辉
FENG Guorui;XIE Wenshuo;GUO Yuxia;GUO Jun;RAN Hongyu;ZHAO Yonghui(College of Mining Engineering,Taiyuan University of Technology,Taiyuan,Shanxi 030024,China;Shanxi Province ResearchCentre of Green Mining Engineering Technology,Taiyuan,Shanxi 030024,China)
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2022年第4期775-784,共10页
Chinese Journal of Rock Mechanics and Engineering
基金
国家自然科学基金资助项目(51974192)
国家杰出青年基金资助项目(51925402)
国家自然科学基金青年基金项目(51904203)。
关键词
采矿工程
矸石胶结充填体
早期受载
力学特性
破坏特征
超声波
声发射
微观机制
mining engineering
cemented gangue backfill
early load
mechanical property
failure characteristic
ultrasound
acoustic emission
microscopic mechanism
