Effects of aggregate size distribution and carbon nanotubes on the mechanical properties of cemented gangue backfill samples under true triaxial compression  

作　　者：Qian Yin Fan Wen Zhigang Tao Hai Pu Tianci Deng Yaoyao Meng Qingbin Meng Hongwen Jing Bo Meng Jiangyu Wu 

机构地区：[1]State Key Laboratory of Intelligent Construction and Healthy Operation and Maintenance of Deep Underground Engineering,China University of Mining and Technology,Xuzhou 221116,China [2]State Key Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mines,Anhui University of Science and Technology,Huainan 232001,China [3]State Key Laboratory for Geomechanics&Deep Underground Engineering,China University of Mining and Technology(Beijing),Beijing 100083,China [4]Key Laboratory of Xinjiang Coal Resources Green Mining,Ministry of Education,Xinjiang Institute of Engineering,Urumqi 830023,China

出　　处：《International Journal of Minerals,Metallurgy and Materials》2025年第2期311-324,共14页矿物冶金与材料学报（英文版）

基　　金：financially supported by the National Natural Science Foundation of China(Nos.52174092,51904290,and 52374147);the Natural Science Foundation of Jiangsu Province,China(No.BK20220157);the Fundamental Research Funds for the Central Universities,China(No.2022YCPY0202);the National Key Research and Development Program of China(No.2023YFC3804204);the Major Program of Xinjiang Uygur Autonomous Region S cience and Technology(No.2023A01002)。

摘　　要：The mechanical behavior of cemented gangue backfill materials(CGBMs)is closely related to particle size distribution(PSD)of aggregates and properties of cementitious materials.Consequently,the true triaxial compression tests,CT scanning,SEM,and EDS tests were conducted on cemented gangue backfill samples(CGBSs)with various carbon nanotube concentrations(P_(CNT))that satisfied fractal theory for the PSD of aggregates.The mechanical properties,energy dissipations,and failure mechanisms of the CGBSs under true triaxial compression were systematically analyzed.The results indicate that appropriate carbon nanotubes(CNTs)effectively enhance the mechanical properties and energy dissipations of CGBSs through micropore filling and microcrack bridging,and the optimal effect appears at P_(CNT)of 0.08wt%.Taking PSD fractal dimension(D)of 2.500 as an example,compared to that of CGBS without CNT,the peak strength(σ_(p)),axial peak strain(ε_(1,p)),elastic strain energy(Ue),and dissipated energy(U_(d))increased by 12.76%,29.60%,19.05%,and90.39%,respectively.However,excessive CNTs can reduce the mechanical properties of CGBSs due to CNT agglomeration,manifesting a decrease inρ_(p),ε_(1,p),and the volumetric strain increment(Δε_(v))when P_(CNT)increases from 0.08wt%to 0.12wt%.Moreover,the addition of CNTs improved the integrity of CGBS after macroscopic failure,and crack extension in CGBSs appeared in two modes:detour and pass through the aggregates.Theσ_(p)and U_(d)firstly increase and then decrease with increasing D,and porosity shows the opposite trend.Theε_(1,p)andΔε_(v)are negatively correlated with D,and CGBS with D=2.150 has the maximum deformation parameters(ε_(1,p)=0.05079,Δε_(v)=0.01990)due to the frictional slip effect caused by coarse aggregates.With increasing D,the failure modes of CGBSs are sequentially manifested as oblique shear failure,"Y-shaped"shear failure,and conjugate shear failure.

关 键 词：cemented gangue backfill materials particle size distribution true triaxial compression test carbon nanotubes mechanical properties failure modes 

分 类 号：TD823.7[矿业工程—煤矿开采]