高应变率下钻孔煤样冲击破坏试验及数值研究  

Test and numerical study on impact failure of drilling coal samples under high strain rate

作　　者：张寅 尹立冬 代连朋 张季平 李家俊 杨晨晨 ZHANG Yin;YIN Lidong;DAI Lianpeng;ZHANG Jiping;LI Jiajun;YANG Chenchen(School of Mechanics and Engineering,Liaoning Technical University,Fuxin 123000,China;Institute of Disaster Rock Mechanics,Liaoning University,Shenyang 110036,China)

机构地区：[1]辽宁工程技术大学力学与工程学院,辽宁阜新123000 [2]辽宁大学灾害岩体力学研究所,沈阳110036

出　　处：《振动与冲击》2024年第9期309-320,共12页Journal of Vibration and Shock

基　　金：国家自然科学基金(52174116);辽宁省科技厅博士启动基金(2023-BS-083)。

摘　　要：煤层钻孔是防治冲击地压常用的一种简单、经济和有效的降冲减灾手段。针对冲击地压发生后高应变率加载显现,揭示钻孔煤岩的冲击破坏物理过程及其减灾机制对于定量化设计煤层钻孔参数意义重大。为研究高应变率下钻孔对煤样力学性质的影响,通过室内霍普金森压杆试验及颗粒流数值模拟对预制孔煤样进行冲击试验。试验结果表明:高应变率加载下钻孔对煤样的动态抗压强度具有显著的弱化作用,随钻孔数目的增加,煤岩动态抗压强度分别下降11.9%、20.4%、23.2%;随钻孔间距的增加,动态抗压强度分别下降20.4%、14.9%、8.5%、16.4%。含钻孔煤样应力-应变曲线存在应力跌落现象与塑性耗能平台期,应力跌落范围与塑性平台范围随孔数目的增加呈上升趋势。高应变率加载下钻孔对煤样的破坏具有明显的变形局部化引导作用,当煤岩破坏时,初始主裂纹于平行加载方向的孔边拉应力区产生,次裂纹垂直主裂纹方向,孔间裂纹于孔桥间产生。应力集中区随孔桥破碎重新分布,孔边承载区远离钻孔。钻孔后煤样的AE(acoustic emission)事件数峰值出现不同程度的后移,当L≤2.5 d时,AE事件分布呈双峰特征,L>2.5d时,AE事件分布呈单峰特征。Coal seam drilling is a simple,economic and effective means to reduce impact and disaster for prevention and control of rock burst.Aiming at high strain rate loading after impact pressure appearing,revealing physical process of impact failure of drilled coal rock and its mitigation mechanism is of great significance for quantitatively designing parameters of coal seam drilling.Here,to study effects of drilling on mechanical properties of coal samples under high strain rate,impact tests were conducted for pre-drilled coal samples through indoor SHPB tests and particle flow numerical simulation.Test results showed that under high strain rate loading,drilling has a significant weakening effect on dynamic compressive strength of coal samples;with increase in drilling number,dynamic compressive strength of coal rock decreases by 11.9%,20.4%and 23.2%,respectively;with increase in spacing between boreholes,coal rock dynamic compressive strength decreases by 20.4%,14.9%,8.5%and 16.4%,respectively;there are phenomena of stress drop and plastic energy dissipation platform period on stress-strain curves of drilled coal samples;stress drop range and plastic platform range have an upward trend with increase in number of holes;under high strain rate loading,drilling has an obvious deformation localization guiding effect on failure of coal samples;during coal rock failure,the initial main crack is generated in hole edge tensile stress zone parallel to loading direction,the secondary crack is perpendicular to the main crack direction,and inter-hole crack is generated at inter-hole bridge;stress concentration areas are redistributed with hole bridge crushing,and hole edge load-bearing area is far away from drilled hole;peak values of AE event number in coal samples after drilling have backward shifts with different degrees;when L≤2.5d,distribution of AE events has a bi-peak feature,while when L>2.5d,distribution of AE events has a single peak feature.

关 键 词：高应变率 霍普金森压杆 颗粒流 裂纹扩展 

分 类 号：TD324[矿业工程—矿井建设]