冻融循环作用下层理砂岩物理特性及劣化模型
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摘要
岩石在冻融环境下发生的损伤与其层理结构密切相关,同时冻融损伤作为一种综合表现,单纯考虑岩体内部某一种尺度缺陷或外部单一因素在冻融循环作用下的变化,不足以客观反映损伤情况。对垂直、平行层理试样开展0、20、40次冻融试验,首先探究了层理砂岩在冻融过程中的损伤发育特征,之后基于Ф100 mm SHPB试验装置,进行5种弹速下的冲击试验,分析了冻融循环条件下层理砂岩冲击破碎块度分布规律,以冻融损伤累积与破碎块度的相关性为理论依据,以力学性质的冻融劣化为思想建立了层理砂岩的冻融劣化模型,研究结果表明:冻融环境下,两种试样孔隙发育、纵波波速表现出显著差异,平行层理试样相对更容易发生损伤;各级冲击弹速下破碎块度分布与冻融循环次数之间存在正相关、负相关以及波动型3种相关关系;劣化模型基于负相关区域数据和成比例相同区域数据得到的强度、峰值应变计算值与实测值非常接近,基于正相关区域数据得到的强度计算值也与实测值有很好的一致性。
The damage of rock caused by freezing and thawing is closely related to its bedding structure, and the freeze-thaw damage is a comprehensive performance. A simple consideration of the change of a single defect inside rock mass or a single external factor under freezing and thawing cycles is insufficient to objectively reflect the damage. In this paper, freeze-thaw tests subjected to 0, 20, 40 freeze-thaw cycles were carried out on the vertical and parallel layered samples. The damage development characteristics of the layered sandstone during the freezing and thawing process were explored. Based on the Ф100 mm SHPB test device, impact tests at five types of speed were carried out, and the distribution law of impact crushed degrees of layered sandstone under the condition of freeze-thaw cycles was analysed. Based on the correlation between the accumulation of freeze-thaw damage and the degree of crushing, a freeze-thaw degradation model of layered sandstone was established by the deterioration of mechanical properties. It is found that under the action of freezing and thawing, the longitudinal wave velocity, pore development and impact crushing morphology of these two types of layered sandstone samples are significantly different. There are three correlations between the degree of fragmentation and the number of freeze-thaw cycles, i.e. positive correlation, negative correlation and fluctuation. The calculated values of the intensity and peak strain obtained from the negative correlation region data, as well as the proportional and overlapping area data, are very close to the measured values. The calculated values of the intensity based on the positive correlation data are also in good agreement with the measured values.
The damage of rock caused by freezing and thawing is closely related to its bedding structure, and the freeze-thaw damage is a comprehensive performance. A simple consideration of the change of a single defect inside rock mass or a single external factor under freezing and thawing cycles is insufficient to objectively reflect the damage. In this paper, freeze-thaw tests subjected to 0, 20, 40 freeze-thaw cycles were carried out on the vertical and parallel layered samples. The damage development characteristics of the layered sandstone during the freezing and thawing process were explored. Based on the Ф100 mm SHPB test device, impact tests at five types of speed were carried out, and the distribution law of impact crushed degrees of layered sandstone under the condition of freeze-thaw cycles was analysed. Based on the correlation between the accumulation of freeze-thaw damage and the degree of crushing, a freeze-thaw degradation model of layered sandstone was established by the deterioration of mechanical properties. It is found that under the action of freezing and thawing, the longitudinal wave velocity, pore development and impact crushing morphology of these two types of layered sandstone samples are significantly different. There are three correlations between the degree of fragmentation and the number of freeze-thaw cycles, i.e. positive correlation, negative correlation and fluctuation. The calculated values of the intensity and peak strain obtained from the negative correlation region data, as well as the proportional and overlapping area data, are very close to the measured values. The calculated values of the intensity based on the positive correlation data are also in good agreement with the measured values.
引文
[1]WANG Peng,XU Jin-yu,LIU Shi,et al.A prediction model for the dynamic mechanical degradation of sedimentary rock after a long-term freeze-thaw weathering:Considering the strain-rate effect[J].Cold Regions Science and Technology,2016,131:16-23.
[2]陈卫忠,谭贤君,于洪丹,等.低温及冻融环境下岩体热,水,力特性研究进展与思考[J].岩石力学与工程学报,2011,30(7):1318-1336.CHEN Wei-zhong,TAN Xian-jun,YU Hong-dan,et al.Advance and review on thermo-hydro-mechanical characteristics of rock mass under condition of low temperature and freeze-thaw cycles[J].Chinese Journal of Rock Mechanics and Engineering,2011,30(7):1318-1336.
[3]杨更社,蒲毅彬,马巍.寒区冻融环境条件下岩石损伤扩展研究探讨[J].实验力学,2002,17(2):220-226.YANG Geng-she,PU Yi-bin,MA Wei.Discussion on the damage propagation for the rock under the frost and thaw condition of frigid zone[J].Journal of Experimental Mechanics,2002,17(2):220-226.
[4]CHEN T C,YEUNG M R,MORIC N.Effect of water saturation on deterioration of welded tuff due to freezethaw action[J].Cold Regions Science and Technology,2004,38(1):127-136.
[5]徐光苗,刘泉声.岩石冻融破坏机理分析及冻融力学试验研究[J].岩石力学与工程学报,2005,24(17):3076-3082.XU Guang-miao,LIU Quan-sheng.Analysis of mechanism of rock failure due to freezing-thawing cycling and mechanical testing study on frozen-thawed rocks[J].Chinese Journal of Rock Mechanics and Engineering,2005,24(17):3076-3082.
[6]张慧梅,杨更社.岩石冻融力学实验及损伤扩展特性[J].中国矿业大学学报,2011,40(1):140-145.ZHANG Hui-mei,YANG Geng-she.Freeze-thaw cycling and mechanical experiment and damage propagation characteristics of rock[J].Journal of China University of Mining and Technology,2011,40(1):140-145.
[7]张继周,缪林昌,杨振峰.冻融条件卜岩石损伤劣化机制和力学特性研究[J].岩石力学与工程学报,2008,27(8):1688-1694.ZHANG Ji-zhou,MIAO Lin-chang,YANG Zhen-feng.Research on rock degradation and deterioration mechanisms and mechanical characteristics under cyclic freezing-thawing[J].Chinese Journal of Rock Mechanics and Engineering,2008,27(8):1688-1694.
[8]李杰林,周科平,张亚民,等.基于核磁共振技术的岩石孔隙结构冻融损伤试验研究[J].岩石力学与工程学报,2012,31(6):1208-1214.LI Jie-lin,ZHOU Ke-ping,ZHANG Ya-min,et al.Experimental study of rock porous structure damage characteristics under condition of freezing-thawing cycles based on nuclear magnetic resonance technique[J].Chinese Journal of Rock Mechanics and Engineering,2012,31(6):1208-1214.
[9]母剑桥,裴向军,黄勇,等.冻融岩体力学特性实验研究[J].工程地质学报,2013,21(1):103-108.MU Jian-qiao,PEI Xiang-jun,HUANG Yong,et al.Experimental research on mechanical characteristics of rock with cycles of freeing-thawing action[J].Journal of Engineering Geology,2013,21(1):103-108.
[10]袁小清,刘红岩,刘京平.冻融荷载耦合作用下节理岩体损伤本构模型[J].岩石力学与工程学报,2015,34(8):1602-1611.YUAN Xiao-qing,LIU Hong-yan,LIU Jing-ping,et al.Adamaging model of jointed rock under coupled action of freezing and thawing[J].Chinese Journal of Rock Mechanics and Engineering,2015,34(8):1602-1611.
[11]刘杰,徐春霖,王瑞红.冻融循环作用下损伤砂岩物理特性研究[J].水力发电学报,2016,35(5):123-130.LIU Jie,XU Chun-lin,WANG Rui-hong.Physical characteristics of sandstone under freeze-thaw cycles[J].Journal of Hydroelectric Engineering,2016,35(5):123-130.
[12]贾海梁,项伟,谭龙,等.砂岩冻融损伤机制的理论分析和试验验证[J].岩石力学与工程学报,2016,35(5):879-895.JIA Hai-liang,XIANG Wei,TAN Long,et al.Theoretical analysis and experimental verifications of frost damage mechanism of sandstone[J].Chinese Journal of Rock Mechanics and Engineering,2016,35(5):879-895.
[13]吴澎.节理岩体的损伤模型及非线性有限元分析[J].岩石力学与工程学报,1988,7(3):193-202.WU Peng.The damage mechanics model for jointed rock mass and its nonlinear FEM analysis[J].Chinese Journal of Rock Mechanics and Engineering,1988,7(3):193-202.
[14]左双英,史文兵,梁风,等.层状各向异性岩体破坏模式判据数值实现及工程应用[J].岩土工程学报,2015,37(1):191-196.ZUO Shuang-ying,SHI Wen-bing,LIANG Feng,et al.Numerical simulation and engineering application for failure modes and criterion of layered anisotropic rock mass[J].Chinese Journal of Geotechnical Engineering,2015,37(1):191-196.
[15]宫凤强,李夕兵,饶秋华,等.岩石SHPB试验中确定试样尺寸的参考方法[J].振动与冲击,2013,32(17):24-32.GONG Feng-qiang,LI Xi-bing,RAO Qiu-hua,et al.Reference method for determining sample size in SHPBtests of rock materials[J].Journal of Vibration and Shock,2013,32(17):24-32.
[16]中国电力企业联合会.GB/T 50266―2013工程岩体试验方法标准[S].北京:中国计划出版社,2013.China Electricity Council.GB/T 50266―2013 Standard for test methods of engineering rock mass[S].Beijing:China Planning Press,2013.
[17]BROWN E T.Rock characterization,testing&monitoring:ISRM suggested methods[M].Oxford:Pergamon Press,1981:81-221.
[18]尤明庆,苏承东,李小双.损伤岩石试样的力学特性与纵波速度关系研究[J].岩石力学与工程学报,2008,27(3):458-467.YOU Ming-qing,SU Cheng-dong,LI Xiao-shuang.Study on relation between mechanical properties and longitudinal wave velocities for damaged rock samples[J].Chinese Journal of Rock Mechanics and Engineering,2008,27(3):458-467.
[19]许金余,刘石.大理岩冲击加载试验碎块的分形特征分析[J].岩土力学,2012,33(11):3225-3229.XU Jin-yu,LIU Shi.Research on fractal characteristics of marble fragments subjected to impact loading[J].Rock and Soil Mechanics,2012,33(11):3225-3229.
[20]戚承志,钱七虎.岩石等脆性材料动力强度依赖应变率的物理机制[J].岩石力学与工程学报,2003,22(2):177-181.QI Cheng-zhi,QIAN Qi-hu.Physical mechanism of dependence of material strength on strain rate for rocklike material[J].Chinese Journal of Rock Mechanics and Engineering,2003,22(2):177-181.
[21]GRADY D E.Shock wave properties of brittle solids[C]//Shock Compression of Condensed Matters.New York:AIP Press,1996.
[22]尹小涛,丁卫华,李春光,等.中等应变速率对砂岩破坏形态和力学性质的影响[J].浙江大学学报(工学版),2010,44(10):1944-1949.YIN Xiao-tao,DING Wei-hua,LI Chun-guang,et al.Rupture and mechanics behavior of sandstone affected by medium strain rate[J].Journal of Zhejiang University(Engineering Science),2010,44(10):1944-1949.
[23]翟越,马国伟,赵均海.花岗岩在单轴冲击压缩荷载下的动态断裂分析[J].岩土工程学报,2007,29(3):385-390.ZHAI Yue,MA Guo-wei,ZHAO Jun-hai.Dynamic failure analysis on granite under uniaxial impact compressive load[J].Chinese Journal of Geotechnical Engineering,2007,29(3):385-390.
[24]CAMBELL J D.FURGUSON W G.The temperature and stress rate dependence of shear strength of mild steel[J].Philosophical Magazine,1970,21(1):63-82.
[25]杜晶,李夕兵,宫凤强,等.岩石冲击实验碎屑分类及其分形特征[J].矿业研究与开发,2010,30(5):20-22.DU Jing,LI Xi-bing,GONG Feng-qiang,et al.Classification and fractal characteristics of the fragments impacting experiment of rock[J].Mining Research and Development,2010,30(5):20-22.
[26]梁昌玉,李晓,张辉,等.中低应变率范围内花岗岩单轴压缩特性的尺寸效应研究[J].岩石力学与工程学报,2013,32(3):529-536.LIANG Chang-yu,LI Xiao,ZHANG Hui,et al.Research on size effect of uniaxial compression properties of granite under medium and low strain rates[J].Chinese Journal of Rock Mechanics and Engineering,2013,32(3):529-536.
[2]陈卫忠,谭贤君,于洪丹,等.低温及冻融环境下岩体热,水,力特性研究进展与思考[J].岩石力学与工程学报,2011,30(7):1318-1336.CHEN Wei-zhong,TAN Xian-jun,YU Hong-dan,et al.Advance and review on thermo-hydro-mechanical characteristics of rock mass under condition of low temperature and freeze-thaw cycles[J].Chinese Journal of Rock Mechanics and Engineering,2011,30(7):1318-1336.
[3]杨更社,蒲毅彬,马巍.寒区冻融环境条件下岩石损伤扩展研究探讨[J].实验力学,2002,17(2):220-226.YANG Geng-she,PU Yi-bin,MA Wei.Discussion on the damage propagation for the rock under the frost and thaw condition of frigid zone[J].Journal of Experimental Mechanics,2002,17(2):220-226.
[4]CHEN T C,YEUNG M R,MORIC N.Effect of water saturation on deterioration of welded tuff due to freezethaw action[J].Cold Regions Science and Technology,2004,38(1):127-136.
[5]徐光苗,刘泉声.岩石冻融破坏机理分析及冻融力学试验研究[J].岩石力学与工程学报,2005,24(17):3076-3082.XU Guang-miao,LIU Quan-sheng.Analysis of mechanism of rock failure due to freezing-thawing cycling and mechanical testing study on frozen-thawed rocks[J].Chinese Journal of Rock Mechanics and Engineering,2005,24(17):3076-3082.
[6]张慧梅,杨更社.岩石冻融力学实验及损伤扩展特性[J].中国矿业大学学报,2011,40(1):140-145.ZHANG Hui-mei,YANG Geng-she.Freeze-thaw cycling and mechanical experiment and damage propagation characteristics of rock[J].Journal of China University of Mining and Technology,2011,40(1):140-145.
[7]张继周,缪林昌,杨振峰.冻融条件卜岩石损伤劣化机制和力学特性研究[J].岩石力学与工程学报,2008,27(8):1688-1694.ZHANG Ji-zhou,MIAO Lin-chang,YANG Zhen-feng.Research on rock degradation and deterioration mechanisms and mechanical characteristics under cyclic freezing-thawing[J].Chinese Journal of Rock Mechanics and Engineering,2008,27(8):1688-1694.
[8]李杰林,周科平,张亚民,等.基于核磁共振技术的岩石孔隙结构冻融损伤试验研究[J].岩石力学与工程学报,2012,31(6):1208-1214.LI Jie-lin,ZHOU Ke-ping,ZHANG Ya-min,et al.Experimental study of rock porous structure damage characteristics under condition of freezing-thawing cycles based on nuclear magnetic resonance technique[J].Chinese Journal of Rock Mechanics and Engineering,2012,31(6):1208-1214.
[9]母剑桥,裴向军,黄勇,等.冻融岩体力学特性实验研究[J].工程地质学报,2013,21(1):103-108.MU Jian-qiao,PEI Xiang-jun,HUANG Yong,et al.Experimental research on mechanical characteristics of rock with cycles of freeing-thawing action[J].Journal of Engineering Geology,2013,21(1):103-108.
[10]袁小清,刘红岩,刘京平.冻融荷载耦合作用下节理岩体损伤本构模型[J].岩石力学与工程学报,2015,34(8):1602-1611.YUAN Xiao-qing,LIU Hong-yan,LIU Jing-ping,et al.Adamaging model of jointed rock under coupled action of freezing and thawing[J].Chinese Journal of Rock Mechanics and Engineering,2015,34(8):1602-1611.
[11]刘杰,徐春霖,王瑞红.冻融循环作用下损伤砂岩物理特性研究[J].水力发电学报,2016,35(5):123-130.LIU Jie,XU Chun-lin,WANG Rui-hong.Physical characteristics of sandstone under freeze-thaw cycles[J].Journal of Hydroelectric Engineering,2016,35(5):123-130.
[12]贾海梁,项伟,谭龙,等.砂岩冻融损伤机制的理论分析和试验验证[J].岩石力学与工程学报,2016,35(5):879-895.JIA Hai-liang,XIANG Wei,TAN Long,et al.Theoretical analysis and experimental verifications of frost damage mechanism of sandstone[J].Chinese Journal of Rock Mechanics and Engineering,2016,35(5):879-895.
[13]吴澎.节理岩体的损伤模型及非线性有限元分析[J].岩石力学与工程学报,1988,7(3):193-202.WU Peng.The damage mechanics model for jointed rock mass and its nonlinear FEM analysis[J].Chinese Journal of Rock Mechanics and Engineering,1988,7(3):193-202.
[14]左双英,史文兵,梁风,等.层状各向异性岩体破坏模式判据数值实现及工程应用[J].岩土工程学报,2015,37(1):191-196.ZUO Shuang-ying,SHI Wen-bing,LIANG Feng,et al.Numerical simulation and engineering application for failure modes and criterion of layered anisotropic rock mass[J].Chinese Journal of Geotechnical Engineering,2015,37(1):191-196.
[15]宫凤强,李夕兵,饶秋华,等.岩石SHPB试验中确定试样尺寸的参考方法[J].振动与冲击,2013,32(17):24-32.GONG Feng-qiang,LI Xi-bing,RAO Qiu-hua,et al.Reference method for determining sample size in SHPBtests of rock materials[J].Journal of Vibration and Shock,2013,32(17):24-32.
[16]中国电力企业联合会.GB/T 50266―2013工程岩体试验方法标准[S].北京:中国计划出版社,2013.China Electricity Council.GB/T 50266―2013 Standard for test methods of engineering rock mass[S].Beijing:China Planning Press,2013.
[17]BROWN E T.Rock characterization,testing&monitoring:ISRM suggested methods[M].Oxford:Pergamon Press,1981:81-221.
[18]尤明庆,苏承东,李小双.损伤岩石试样的力学特性与纵波速度关系研究[J].岩石力学与工程学报,2008,27(3):458-467.YOU Ming-qing,SU Cheng-dong,LI Xiao-shuang.Study on relation between mechanical properties and longitudinal wave velocities for damaged rock samples[J].Chinese Journal of Rock Mechanics and Engineering,2008,27(3):458-467.
[19]许金余,刘石.大理岩冲击加载试验碎块的分形特征分析[J].岩土力学,2012,33(11):3225-3229.XU Jin-yu,LIU Shi.Research on fractal characteristics of marble fragments subjected to impact loading[J].Rock and Soil Mechanics,2012,33(11):3225-3229.
[20]戚承志,钱七虎.岩石等脆性材料动力强度依赖应变率的物理机制[J].岩石力学与工程学报,2003,22(2):177-181.QI Cheng-zhi,QIAN Qi-hu.Physical mechanism of dependence of material strength on strain rate for rocklike material[J].Chinese Journal of Rock Mechanics and Engineering,2003,22(2):177-181.
[21]GRADY D E.Shock wave properties of brittle solids[C]//Shock Compression of Condensed Matters.New York:AIP Press,1996.
[22]尹小涛,丁卫华,李春光,等.中等应变速率对砂岩破坏形态和力学性质的影响[J].浙江大学学报(工学版),2010,44(10):1944-1949.YIN Xiao-tao,DING Wei-hua,LI Chun-guang,et al.Rupture and mechanics behavior of sandstone affected by medium strain rate[J].Journal of Zhejiang University(Engineering Science),2010,44(10):1944-1949.
[23]翟越,马国伟,赵均海.花岗岩在单轴冲击压缩荷载下的动态断裂分析[J].岩土工程学报,2007,29(3):385-390.ZHAI Yue,MA Guo-wei,ZHAO Jun-hai.Dynamic failure analysis on granite under uniaxial impact compressive load[J].Chinese Journal of Geotechnical Engineering,2007,29(3):385-390.
[24]CAMBELL J D.FURGUSON W G.The temperature and stress rate dependence of shear strength of mild steel[J].Philosophical Magazine,1970,21(1):63-82.
[25]杜晶,李夕兵,宫凤强,等.岩石冲击实验碎屑分类及其分形特征[J].矿业研究与开发,2010,30(5):20-22.DU Jing,LI Xi-bing,GONG Feng-qiang,et al.Classification and fractal characteristics of the fragments impacting experiment of rock[J].Mining Research and Development,2010,30(5):20-22.
[26]梁昌玉,李晓,张辉,等.中低应变率范围内花岗岩单轴压缩特性的尺寸效应研究[J].岩石力学与工程学报,2013,32(3):529-536.LIANG Chang-yu,LI Xiao,ZHANG Hui,et al.Research on size effect of uniaxial compression properties of granite under medium and low strain rates[J].Chinese Journal of Rock Mechanics and Engineering,2013,32(3):529-536.