循环荷载下花岗岩应力门槛值的细观能量演化及岩爆倾向性
|
摘要
为研究三轴循环加卸载条件下三山岛花岗岩细观能量演化规律,采用颗粒流理论确定了花岗岩的应力门槛值(起裂应力σci、损伤应力σcd和峰值强度σf),研究了应力门槛值对应的边界能、应变能(线性接触应变能和平行黏结应变能)、耗散能(摩擦能和阻尼能)、动能随围压变化的规律,并从能量角度建立了岩爆倾向性评价指标Wx.结果表明:三山岛花岗岩不同围压下相应的σci/σf位于37. 0%～44. 8%区间,σcd/σf位于81. 2%～89. 0%区间,随着围压的增大,起裂边界能、应变能和耗散能呈线性关系增加,损伤(峰值)边界能、应变能和耗散能呈指数关系增加;其中耗散能受围压影响最为敏感,增幅倍数最大,其次是边界能,最后为应变能.围压对起裂应变能比例影响不大,损伤和峰值应变能比例随围压增大缓慢减小,峰值应变能比例下降幅度最大.基于岩爆倾向性评价指标Wx可知,当围压在20 MPa内,三山岛花岗岩岩爆倾向性相对较小;当围压达到30 MPa时岩爆倾向性开始迅速增加.研究成果为岩爆倾向性的评价提供了新的参考指标,进一步为井下岩体工程的稳定性研究提供了新思路.
To study the meso-energy evolution of Sanshandao granite under triaxial cyclic loading and unloading,the stress thresholds( the crack initiation stress σci,crack damage stress σcd,and peak stress σf) of Sanshandao granite were determined; the variation law of the boundary energy,strain energy( linear contact strain energy and parallel bond strain energy),dissipation energy( friction energy and damping energy),and kinetic energy corresponding to each stress threshold with confining pressures was analyzed; and a new index Wxfor evaluating the rock burst proneness was established from the perspective of energy based on a simulation using PFC3 D. The results show that the corresponding σci/σfis in the range of 37. 0% to 44. 8%,and σcd/σfis in the range of 81. 2% to89. 0% under different confining pressures. With the increase of confining pressure,the boundary energy,strain energy,and dissipation energy of the crack initiation increase linearly,and the boundary energy,strain energy,and dissipation energy of the crack damage and peak increase exponentially. Among them,the dissipation energy exhibits the maximum increment with the change in confining pressure,followed by the boundary energy,and then the strain energy. The confining pressure has little effect on the proportion of the strain energy of crack initiation. Moreover,with increasing pressure,the proportion of the crack damage and the peak strain energy decrease slowly; however,the proportion of peak strain energy decreases to a greater extent. According to the new index Wxfor the evaluation of the rock burst proneness,when the confining pressure was less than 20 MPa,the rock burst proneness of Sanshandao granite was relatively small,and when the confining pressure reached 30 MPa,the rock burst proneness began to increase rapidly. This study provides a new reference index for the evaluation of rock burst proneness and further provides a new idea for the stability study of underground rock mass engineering.
To study the meso-energy evolution of Sanshandao granite under triaxial cyclic loading and unloading,the stress thresholds( the crack initiation stress σci,crack damage stress σcd,and peak stress σf) of Sanshandao granite were determined; the variation law of the boundary energy,strain energy( linear contact strain energy and parallel bond strain energy),dissipation energy( friction energy and damping energy),and kinetic energy corresponding to each stress threshold with confining pressures was analyzed; and a new index Wxfor evaluating the rock burst proneness was established from the perspective of energy based on a simulation using PFC3 D. The results show that the corresponding σci/σfis in the range of 37. 0% to 44. 8%,and σcd/σfis in the range of 81. 2% to89. 0% under different confining pressures. With the increase of confining pressure,the boundary energy,strain energy,and dissipation energy of the crack initiation increase linearly,and the boundary energy,strain energy,and dissipation energy of the crack damage and peak increase exponentially. Among them,the dissipation energy exhibits the maximum increment with the change in confining pressure,followed by the boundary energy,and then the strain energy. The confining pressure has little effect on the proportion of the strain energy of crack initiation. Moreover,with increasing pressure,the proportion of the crack damage and the peak strain energy decrease slowly; however,the proportion of peak strain energy decreases to a greater extent. According to the new index Wxfor the evaluation of the rock burst proneness,when the confining pressure was less than 20 MPa,the rock burst proneness of Sanshandao granite was relatively small,and when the confining pressure reached 30 MPa,the rock burst proneness began to increase rapidly. This study provides a new reference index for the evaluation of rock burst proneness and further provides a new idea for the stability study of underground rock mass engineering.
引文
[1] Zhou H,Meng F Z,Zhang C Q,et al. Characteristics and mechanism of occurrence of stress thresholds and corresponding strain for hard rock. Chin J Rock Mech Eng,2015,34(8):1513(周辉,孟凡震,张传庆,等.硬岩应力--应变门槛值特点及产生机制.岩石力学与工程学报,2015,34(8):1513)
[2] Heng S,Yang C H,Li Z,et al. Shale brittleness estimation based on energy dissipation. J Cent South Univ Sci Technol,2016,47(2):577(衡帅,杨春和,李芷,等.基于能量耗散的页岩脆性特征.中南大学学报(自然科学版),2016,47(2):577)
[3] Wen T,Tang H M,Liu Y R,et al. Energy and damage analysis of slate during triaxial compression under different confining pressures. Coal Geol Expl,2016,44(3):80(温韬,唐辉明,刘佑荣,等.不同围压下板岩三轴压缩过程能量及损伤分析.煤田地质与勘探,2016,44(3):80)
[4] Deng H F,Hu Y,Li J L,et al. The evolution of sandstone energy dissipation under cyclic loading and unloading. Chin J Rock Mech Eng,2016,35(Suppl 1):2869(邓华锋,胡玉,李建林,等.循环加卸载过程中砂岩能量耗散演化规律.岩石力学与工程学报,2016,35(增刊1):2869)
[5] Xie H P,Ju Y,Li L Y,et al. Energy mechanism of deformation and failure of rock masses. Chin J Rock Mech Eng,2008,27(9):1729(谢和平,鞠杨,黎立云,等.岩体变形破坏过程的能量机制.岩石力学与工程学报,2008,27(9):1729)
[6] Zhang Z Z,Gao F. Experimental investigations on energy evolution characteristics of coal,sandstone and granite during loading process. J China Univ Mining Technol,2015,44(3):416(张志镇,高峰. 3种岩石能量演化特征的试验研究.中国矿业大学学报,2015,44(3):416)
[7] Kidybiński A. Bursting liability indices of coal. Int J Rock Mech Min Sci Geomech Abstracts,1981,18(4):295
[8] Wang J A,Park H D. Comprehensive prediction of rock burst based on analysis of strain energy in rocks. Tunnell Undergr Space Technol,2001,16(1):49
[9] Aubertin M,Gill D E,Simon R. On the use of the brittleness index modified(BIM)to estimate the post-peak behavior or rocks//1st North American Rock Mechanics Symposium. Austin,1994:ARMA-1994-0945
[10] Liu S X,Lu S Z,Chen Y. Study on rockburst proneness of a deep mine based on multiple criterions. Min Res Dev,2017,37(2):9(刘树新,鲁思佐,陈阳.基于多重判据的某深部矿区岩爆倾向性研究.矿业研究与开发,2017,37(2):9)
[11] Tang L Z,Pan C L,Wang W X. Surplus energy index for analyzing rock burst proneness. J Cent South Univ Technol,2002,33(2):129(唐礼忠,潘长良,王文星.用于分析岩爆倾向性的剩余能量指数.中南工业大学学报,2002,33(2):129)
[12] Tang L Z,Wang W X. New rock burst proneness index. Chin J Rock Mech Eng,2002,21(6):874(唐礼忠,王文星.一种新的岩爆倾向性指标.岩石力学与工程学报,2002,21(6):874)
[13] Simon R. Analysis of Fault-Slip Mechanisms in Hard Rock Mining[Dissertation]. Montreal:Mc Gill University,1999
[14] Potyondy D O,Cundall P A. A bonded-particle model for rock.Int J Rock Mech Min Sci,2004,41(8):1329
[15] Martin C D,Chandler N A. The progressive fracture of Lac du Bonnet granite. Int J Rock Mech Min Sci Geomech Abstracts,1994,31(6):643
[16] Brace W F,Paulding Jr B W,Scholz C H. Dilatancy in the fracture of crystalline rocks. J Geophys Res,1966,71(16):3939
[17] Hoek E,Bieniawski Z T. Brittle fracture propagation in rock under compression. Int J Fract Mech,1965,1(3):137
[18] Hallbauer D K,Wagner H,Cook N G W. Some observations concerning the microscopic and mechanical behaviour of quartzite specimens in stiff,triaxial compression tests. Int J Rock Mech Min Sci Geomech Abstracts,1973,10(6):713
[19] Singh S P. Classification of mine workings according to their rockburst proneness. Min Sci Technol,1989,8(3):253
[20] Cai M F,Ji D,Guo Q F. Study of rockburst prediction based on in-situ stress measurement and theory of energy accumulation caused by mining disturbance. Chin J Rock Mech Eng,2013,32(10):1973(蔡美峰,冀东,郭奇峰.基于地应力现场实测与开采扰动能量积聚理论的岩爆预测研究.岩石力学与工程学报,2013,32(10):1973)
[2] Heng S,Yang C H,Li Z,et al. Shale brittleness estimation based on energy dissipation. J Cent South Univ Sci Technol,2016,47(2):577(衡帅,杨春和,李芷,等.基于能量耗散的页岩脆性特征.中南大学学报(自然科学版),2016,47(2):577)
[3] Wen T,Tang H M,Liu Y R,et al. Energy and damage analysis of slate during triaxial compression under different confining pressures. Coal Geol Expl,2016,44(3):80(温韬,唐辉明,刘佑荣,等.不同围压下板岩三轴压缩过程能量及损伤分析.煤田地质与勘探,2016,44(3):80)
[4] Deng H F,Hu Y,Li J L,et al. The evolution of sandstone energy dissipation under cyclic loading and unloading. Chin J Rock Mech Eng,2016,35(Suppl 1):2869(邓华锋,胡玉,李建林,等.循环加卸载过程中砂岩能量耗散演化规律.岩石力学与工程学报,2016,35(增刊1):2869)
[5] Xie H P,Ju Y,Li L Y,et al. Energy mechanism of deformation and failure of rock masses. Chin J Rock Mech Eng,2008,27(9):1729(谢和平,鞠杨,黎立云,等.岩体变形破坏过程的能量机制.岩石力学与工程学报,2008,27(9):1729)
[6] Zhang Z Z,Gao F. Experimental investigations on energy evolution characteristics of coal,sandstone and granite during loading process. J China Univ Mining Technol,2015,44(3):416(张志镇,高峰. 3种岩石能量演化特征的试验研究.中国矿业大学学报,2015,44(3):416)
[7] Kidybiński A. Bursting liability indices of coal. Int J Rock Mech Min Sci Geomech Abstracts,1981,18(4):295
[8] Wang J A,Park H D. Comprehensive prediction of rock burst based on analysis of strain energy in rocks. Tunnell Undergr Space Technol,2001,16(1):49
[9] Aubertin M,Gill D E,Simon R. On the use of the brittleness index modified(BIM)to estimate the post-peak behavior or rocks//1st North American Rock Mechanics Symposium. Austin,1994:ARMA-1994-0945
[10] Liu S X,Lu S Z,Chen Y. Study on rockburst proneness of a deep mine based on multiple criterions. Min Res Dev,2017,37(2):9(刘树新,鲁思佐,陈阳.基于多重判据的某深部矿区岩爆倾向性研究.矿业研究与开发,2017,37(2):9)
[11] Tang L Z,Pan C L,Wang W X. Surplus energy index for analyzing rock burst proneness. J Cent South Univ Technol,2002,33(2):129(唐礼忠,潘长良,王文星.用于分析岩爆倾向性的剩余能量指数.中南工业大学学报,2002,33(2):129)
[12] Tang L Z,Wang W X. New rock burst proneness index. Chin J Rock Mech Eng,2002,21(6):874(唐礼忠,王文星.一种新的岩爆倾向性指标.岩石力学与工程学报,2002,21(6):874)
[13] Simon R. Analysis of Fault-Slip Mechanisms in Hard Rock Mining[Dissertation]. Montreal:Mc Gill University,1999
[14] Potyondy D O,Cundall P A. A bonded-particle model for rock.Int J Rock Mech Min Sci,2004,41(8):1329
[15] Martin C D,Chandler N A. The progressive fracture of Lac du Bonnet granite. Int J Rock Mech Min Sci Geomech Abstracts,1994,31(6):643
[16] Brace W F,Paulding Jr B W,Scholz C H. Dilatancy in the fracture of crystalline rocks. J Geophys Res,1966,71(16):3939
[17] Hoek E,Bieniawski Z T. Brittle fracture propagation in rock under compression. Int J Fract Mech,1965,1(3):137
[18] Hallbauer D K,Wagner H,Cook N G W. Some observations concerning the microscopic and mechanical behaviour of quartzite specimens in stiff,triaxial compression tests. Int J Rock Mech Min Sci Geomech Abstracts,1973,10(6):713
[19] Singh S P. Classification of mine workings according to their rockburst proneness. Min Sci Technol,1989,8(3):253
[20] Cai M F,Ji D,Guo Q F. Study of rockburst prediction based on in-situ stress measurement and theory of energy accumulation caused by mining disturbance. Chin J Rock Mech Eng,2013,32(10):1973(蔡美峰,冀东,郭奇峰.基于地应力现场实测与开采扰动能量积聚理论的岩爆预测研究.岩石力学与工程学报,2013,32(10):1973)