考虑初始缺陷的超高矿柱蠕变分析及失稳滞后时间研究
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摘要
根据超高矿柱结构及受力特点,并充分考虑初始几何偏差,建立了简化的压杆力学模型.基于弹塑性理论对具有初始几何缺陷的超高矿柱的挠度及内力进行了分析,并基于Kachanov损伤理论,对超高矿柱的损伤过程和失稳时间进行了研究.结果表明,在初始挠度的影响下,矿柱将出现不同程度的附加挠度,大小与初始挠度和压力比(上覆压力与矿柱极限荷载之比)有关,随着初始挠度和压力比的增加而增加.工程实例分析表明,矿柱的损伤孕育时间和失稳滞后时间与初始挠度、压力比及抗压强度有密切的关系,随着压力比和初始挠度增加,损伤孕育时间和失稳滞后时间快速变小,抗压强度越大,失稳滞后时间越大,即矿柱越稳定.
According to the ultrahigh pillar structure and mechanical characteristics,considering the initial geometric deviation caused by mining disturbance,the simplified model of the pressure bar was established.Based on elastic-plastic theory,the deflection and internal forces of ultrahigh pillar with initial geometric imperfections were analyzed and discussed.And based on the Kachanov theory of damage,the damage of ultrahigh pillar and damage failure time were analyzed.The results show that under the influence of the initial deflection,pillar will appear different degree of additional deflection,which grows with the increasing of initial deflection and pressure ratio.The start time of damage and instability of delay time of pillar has close relationship with initial deflection,pressure ratio and compressive strength.With the increase of pressure ratio and initial deflection,the damage incubation time and the instability of delay time quickly become small,the greater the compressive strength,the greater the instability of the delay time,which means that the pillar is more stable.
According to the ultrahigh pillar structure and mechanical characteristics,considering the initial geometric deviation caused by mining disturbance,the simplified model of the pressure bar was established.Based on elastic-plastic theory,the deflection and internal forces of ultrahigh pillar with initial geometric imperfections were analyzed and discussed.And based on the Kachanov theory of damage,the damage of ultrahigh pillar and damage failure time were analyzed.The results show that under the influence of the initial deflection,pillar will appear different degree of additional deflection,which grows with the increasing of initial deflection and pressure ratio.The start time of damage and instability of delay time of pillar has close relationship with initial deflection,pressure ratio and compressive strength.With the increase of pressure ratio and initial deflection,the damage incubation time and the instability of delay time quickly become small,the greater the compressive strength,the greater the instability of the delay time,which means that the pillar is more stable.
引文
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[5]WHITTLES D N,LOWNDES I S,KINGQMAN S W,et al.The stability of methane capture boreholes around a long wall coal panel[J].International Journal of Coal Geology,2007,71(2-3):313-328.
[6]BAHUQUNA P P.Subsidence studies in Indian coalfields by a semi-empirical approach[J].LAHSAISH Publication,1995(234):127-133.
[7]彭赐灯.矿山压力与岩层控制研究热点最新进展评述[J].中国矿业大学学报,2015,44(1):1-8.PENG Syd S.Topical areas of research need in ground control:A state of the art review on coal mine ground control[J].Journal of China University of Mining&Technology,2015,44(1):1-8.
[8]WU H,ZHANG N,WANG W,et al.Characteristics of deformation and stress distribution of small coal pillars under leading abutment pressure[J].International Journal of Mining Science and Technology,2015,25(6):921-926.
[9]王金安,李大钟,尚新春.采空区坚硬顶板流变破断力学分析[J].北京科技大学学报,2011,33(2):142-148.WANG Jinan,LI Dazhong,SHANG Xinchun.Mechanics analysis on creep fracture of strong roof strata above mined-out area[J].Journal of University of Science and Technology Beijing,2011,33(2):142-148.
[10]贺广零,黎都春,翟志文,等.采空区煤柱-顶板系统失稳的力学分析[J].煤炭学报,2007,32(9):897-901.HE Guangling,LI Duchun,ZHAI Zhiwen,et al.Analysis of instability of coal pillar and stiff roof system[J].Journal of China coal society,2007,32(9):897-901.
[11]李宏,徐曾和,徐小荷,等.非对称开采时矿柱岩爆的准则与前兆[J].中国矿业,1997,6(1):46-51.LI Hong,XU Zenghe,XU Xiaohe,et al.Criterions and forewarning of ore pillar rock bursts in asymmetric mining[J].China Mining Magazine,1997,6(1):46-51.
[12]EXADAKTYLOS G,TSOUTRELIS C E.Pillar failure by axial splitting in brittle rocks[J].International Journal of Rock Mechanics&Mining Sciences&Geomechanics Abstracts,1995,32(6):551-562.
[13]尹升华,吴爱祥,李希雯.矿柱稳定性影响因素敏感性正交极差分析[J].煤炭学报,2012,37(增1):47-52.YI Shenghua,WU Aixiang,LI Xiwen.Orthogonal polar difference analysis for sensitivity of the factors influencing the ore pillar stability[J].Journal of China Coal Society,2012,37(Sup 1):47-52.
[14]付建新.深部硬岩矿山采空区损伤演化机理及稳定性控制[D].北京科技大学,2015.
[15]王其虎,叶义成,刘艳章,等.考虑初始损伤和蠕变损伤的岩石蠕变全过程本构模型[J].岩土力学,2016,37(增1):57-62.WANG Qihu,YE Yicheng,LIU Yangzhang,et al.A creep constitutive model of rock considering initial damage and creep damage[J].Rock and Soil Mechanics,2016,37(Sup 1):57-62.