围岩-充填体组合承载宏细观损伤演化机理  

Macro-meso damage evolution mechanism of surrounding rock-backfill combination bearing

作　　者：张雯[1] 李泽峰 郭利杰 郭进平[1] 王小林[1] 张宝华 ZHANG Wen;LI Zefeng;GUO Lijie;GUO Jinping;WANG Xiaolin;ZHANG Baohua(School of Resource Engineering,Xi′an University of Architecture and Technology,Xi'an,Shaanxi 710055,China;BGRIMM Technology Group,Beijing 100160,China)

机构地区：[1]西安建筑科技大学资源工程学院,陕西西安710055 [2]矿冶科技集团有限公司,北京100160

出　　处：《中国矿业大学学报》2024年第2期277-290,共14页Journal of China University of Mining & Technology

基　　金：国家自然科学基金青年项目(51904220);国家自然科学基金面上项目(52274122)。

摘　　要：充填体与围岩共同承载地应力,揭示其组合体宏细观损伤演化机理有助于完善充填体与围岩相互作用理论和优化充填体的配比和强度设计.开展不同灰砂比的围岩-充填体组合体单轴压缩试验和数值模拟,分析宏观下应力-应变曲线、力学参数及破坏模式,细观下裂纹扩展、能量变化及损伤演化规律.结果表明:灰砂比越高,组合体的峰值强度和弹性模量越大,峰值应变越小;组合体发生张拉剪切混合式破坏,低灰砂比时接触界面产生断裂破坏,高灰砂比时分层界面产生宏观裂隙;峰前阶段,接触界面和分层界面等薄弱部分先出现微裂纹,组合体以弹性应变能的转化为主,伴随小幅度能量损耗,损伤程度较低;峰后阶段,组合体耗散能急速增长并超过弹性应变能,内部损伤程度加速恶化.围岩内部裂纹数量大幅增加并迅速扩展贯通,率先出现宏观断裂面,充填体内部裂纹汇聚合并于分层界面,在高灰砂比时发挥良好的协同支护作用.The backfill and surrounding rock collectively bear the in-situ stress,and revealing the macroscopic-mesoscopic damage evolution mechanism of the composite body can help to improve the theory of interaction between backfill and surrounding rock,as well as to optimize cement tailing ratios(CTR)and strength design of backfill.Uniaxial compression experiments and numerical simulations were conducted to investigate the surrounding rock-backfill composite specimens with different CTR.The stress-strain curves,mechanical properties,and failure modes at the macroscopic level were analyzed,as well as the crack propagation,energy evolution,and damage evolution mechanism at the mesoscopic level.The results show that with the increase of CTR,the peak strength and modulus of elasticity increase,and the peak strain decreases.The uniaxial failure mode is tensile-shear mixed.Fracture damage occurs at the contact interface when the CTR is low,whereas macroscopic cracks appear at the layered interface when the CTR is high.In the pre-peak stage,microcracks first appear in weak areas such as the contact interface and layered interface.The total energy is primarily transformed through elastic strain energy,with small amplitude energy loss and a low degree of damage.In the post-peak stage,dissipation energy increases rapidly and exceeds the elastic strain energy,leading to accelerated deterioration of internal damage.The number of cracks in the surrounding rock has increased significantly and rapidly,with macroscopic fracture surfaces appearing first.The internal cracks in the backfill converge and merge at the layered interface,which plays a significant synergistic support role when the CTR is high.

关 键 词：围岩-充填体 结构界面 裂纹扩展 能量演化 损伤演化机理 

分 类 号：TD853[矿业工程—金属矿开采]