三轴循环预损后花岗岩单轴声发射及混沌分形分析  

Uniaxial acoustic emission and chaotic fractal analysis of granite pre-damaged by triaxial cyclic loading

作　　者：杨东杰[1] 胡建华[1] 曾平平 YANG Dong-jie;HU Jian-hua;ZENG Ping-ping(School of Resources and Safety Engineering,Central South University,Changsha 410083,China)

机构地区：[1]中南大学资源与安全工程学院,长沙410083

出　　处：《中国有色金属学报》2023年第2期619-629,共11页The Chinese Journal of Nonferrous Metals

基　　金：国家重点研究发展计划资助项目(2017YFC0602901);国家自然科学基金资助项目(4722298)。

摘　　要：周期荷载作用下的岩石力学性能是影响岩体工程长期稳定的重要因素之一,尤其对于深地开采及大型地下硐室等建设工程,需研究循环荷载作用后的深地岩石力学特性。本文主要设计了不同围压和恒定循环上下限荷载条件下,不同循环加卸载次数的花岗岩预损实验,并将预损后的岩石进行单轴压缩实验,同时利用声发射监测损伤后花岗岩破裂的全过程。结果表明:高围压和循环次数均削弱了花岗岩的承载能力,导致其塑性变形能力趋于增强;受高围压和循环次数的影响,预损后的花岗岩声发射振铃计数最大值和累计振铃计数均发生了较大的变化,且均大于天然花岗岩的声发射累计振铃计数;高围压循环荷载预损实验改变了花岗岩关联维数与应力比之间的变化模式,由上升→波动→上升模式转变为波动→缓慢上升(高围压影响,除50 MPa外)或下降→波动上升(循环次数影响)。The mechanical properties of rock under cyclic loading are important to the long-term stability of rock mass engineering works,especially deep mining and large underground chambers.It is necessary to study the mechanical properties of deeply buried rock after cyclic loading.The experimental scheme of the rock pre-damage for different cycles under different confining pressures and constant cyclic upper and lower limit loads was designed.The pre-damaged rock was subjected to uniaxial compression experiment,and monitoring the whole process of dynamic fracture of granite after damage by acoustic emission equipment.The results show that high confining pressure and cycle times both weaken the bearing capacity of granite,and the plastic deformation capacity of rock tends to increase.Affected by the high confining pressure and the number of cycles,the maximum value of the acoustic emission ringing count and the cumulative ringing count of the pre-damaged granite have undergone major changes,and both are greater than the acoustic emission cumulative ringing count of natural granite.The pre-damage experiment of cyclic loading under high confining pressure changed the pattern of changes between the correlation dimension and the stress ratio,from rise-fluctuation-rise mode to fluctuation-slow rise(high confining pressure influence,except 50 MPa)or decline-fluctuation rise(cycle number influence).

关 键 词：高围压 循环荷载 预损 声发射 混沌分形 

分 类 号：TD85[矿业工程—金属矿开采]