隧道仰坡落石冲击模型试验研究与机制探讨
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摘要
以在建的成都-兰州(成兰)铁路某隧道出口仰坡为研究对象,研发了大型落石冲击边坡模型试验系统,该系统由模型试验台架、落石三维空间释放装置、高速摄影系统等组成,结构强度高并能满足试验过程的可视化需求。根据现场岩样实测物理力学参数,采用凡士林、硅油、水泥、细沙、重晶石粉、石膏以及滑石粉等原料,研制出现场千枚岩和砂岩的相似材料,并用于模拟边坡和落石。通过开展物理模型试验研究了近长方体落石初始滑移角度、形状、质量等3种因素对碰撞恢复系数这一落石运动轨迹模拟中关键参数的影响,同时在落石下落冲击的过程中,利用高速摄影仪和坐标卡尺记录落石完整的运动轨迹,后期通过视频处理软件分析落石与边坡碰撞前后的速度变化,根据公式计算出落石法向和切向的碰撞恢复系数。试验结果表明:随着初始滑移角度的增加,板状试件的法向、切向恢复系数分别呈减小和增大的趋势,且切向恢复系数变化更加明显;落石法向恢复系数随质量的增加呈明显减小的趋势,而切向恢复系数值变化不大;对于近长方体落石,立方体试件的法向和切向恢复系数大于厚板状试件,条形试件的两向恢复系数值受碰撞接触形态的影响,呈现两极化的趋势。最后,结合试验现象以及前人的研究成果对落石运动冲击机制进行了初步探讨。
A large model testing system was developed to simulate the rockfall impacting the slope of tunnel exit of Chengdu-Lanzhou railway which is under construction in the southwest area of China. The system is composed of the model testing bench, three-dimensional rockfall release device and high-speed photographic system. This system with high structural strength can meet the visual requirements in the testing process. Based on the measured physical and mechanical parameters of rock specimens, similar materials to phyllite and sandstone were developed to simulate slopes and rockfall by mixing with different proportions of vaseline, silicone oil, cement, fine sand, barite powder, gypsum and talcum powder. The effects of the initial slip angle, shape and mass of cuboid rockfall on the coefficients of restitution were studied through the physical model tests. Besides, a high-speed camera and coordinate callipers were adopted to record the complete trajectories of rock blocks during the rockfall process. At last, a video processing software was employed to analyze the variation of velocity before and after the collision between the rockfall and the slope, and the normal and tangential restitution coefficients of the rockfall were calculated by formulas. The testing results showed that with the increase of the initial slip angle, the normal restitution coefficient of the plate specimen increased, whereas the tangential restitution coefficient decreased and its variation was more obvious. The normal restitution coefficient had a remarkable decreasing trend with an increase of rock mass, but the tangential restitution coefficient seldom changed. For cuboid rock blocks, the normal and tangential restitution coefficients of cuboid specimens are larger than those of thick plate specimens. The normal and tangential restitution coefficients of strip specimens exhibited a polarisation trend due to different contact forms. Finally, the impact mechanism of rockfall was explored according to testing results and previous research results.
A large model testing system was developed to simulate the rockfall impacting the slope of tunnel exit of Chengdu-Lanzhou railway which is under construction in the southwest area of China. The system is composed of the model testing bench, three-dimensional rockfall release device and high-speed photographic system. This system with high structural strength can meet the visual requirements in the testing process. Based on the measured physical and mechanical parameters of rock specimens, similar materials to phyllite and sandstone were developed to simulate slopes and rockfall by mixing with different proportions of vaseline, silicone oil, cement, fine sand, barite powder, gypsum and talcum powder. The effects of the initial slip angle, shape and mass of cuboid rockfall on the coefficients of restitution were studied through the physical model tests. Besides, a high-speed camera and coordinate callipers were adopted to record the complete trajectories of rock blocks during the rockfall process. At last, a video processing software was employed to analyze the variation of velocity before and after the collision between the rockfall and the slope, and the normal and tangential restitution coefficients of the rockfall were calculated by formulas. The testing results showed that with the increase of the initial slip angle, the normal restitution coefficient of the plate specimen increased, whereas the tangential restitution coefficient decreased and its variation was more obvious. The normal restitution coefficient had a remarkable decreasing trend with an increase of rock mass, but the tangential restitution coefficient seldom changed. For cuboid rock blocks, the normal and tangential restitution coefficients of cuboid specimens are larger than those of thick plate specimens. The normal and tangential restitution coefficients of strip specimens exhibited a polarisation trend due to different contact forms. Finally, the impact mechanism of rockfall was explored according to testing results and previous research results.
引文
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[6]何思明,吴永,李新坡.滚石冲击碰撞恢复系数研究[J].岩土力学,2009,30(3):623-627.HE Si-ming,WU Yong,LI Xin-po.Research on restitution coefficient of rock fall[J].Rock and Soil Mechanics,2009,30(3):623-627.
[7]章广成,向欣,唐辉明.落石碰撞恢复系数的现场试验与数值计算[J].岩石力学与工程学报,2011,30(6):1266-1273.ZHANG Guang-cheng,XIANG Xin,TANG Hui-ming.Field test and numerical calculation of restitution coefficient of rockfall collision[J].Chinese Journal of Rock Mechanics and Engineering,2011,30(6):1266-1273.
[8]CHAU K T,WONG R H C,LIU J,et al.Shape effects on the coefficient of restitution during rockfall impacts[C]//Proceedings of 9th International Congress on Rock Mechanics,ISRM.Paris:[s.n.],1999.
[9]CHAU K T,WU J J,WONG R H,et al.The coefficient of restitution for boulders falling onto soil slopes with various values of dry density and water content[C]//Proc.Int.Symp.On Slope Stability Engineering:Geotechnical and Geoenvironmental Aspects.[S.l.]:[s.n.],1999.
[10]HEIDENREICH B,LABIOUSE V.Small-scale laboratory experiments of boulders bouncing on granular slopes[C]//Proceedings of 10th International Congress on Rock Mechanics,ISRM.Johannesburg:[s.n.],2003.
[11]LABIOUSE V,HEIDENREICH B.Half-scale experimental study of rockfall impacts on sandy slopes[J].Natural Hazards and Earth System Science,2009,9(6):1981-1993.
[12]PFEIFFER T J,BOWEN T D.Computer simulation of rockfalls[J].Bulletin of the Association of Engineering Geologists,1989,26(1):135-146.
[13]AGLIARDI F,CROSTA G B.High resolution three-dimensional numerical modelling of rockfalls[J].International Journal of Rock Mechanics and Mining Sciences,2003,40(4):455-471.
[14]GUZZETTI F,CROSTA G,DETTI R,et al.Stone:a computer program for the three-dimensional simulation of rock-falls[J].Computers&Geosciences,2002,28(9):1079-1093.
[15]姚文莉,岳嵘.有争议的碰撞恢复系数研究进展[J].振动与冲击,2015,34(19):43-48.YAO Wen-li,YUE Rong.Advance in controversial restitution coefficient study for impact problems[J].Journal of Vibration and Shock,2015,34(19):43-48.
[16]李仲奎,卢达溶,中山元,等.三维模型试验新技术及其在大型地下洞群研究中的应用[J].岩石力学与工程学报,2003,22(9):1430-1436.LI Zhong-kui,LU Da-rong,NAKAYAMA H,et al.Development and application of new technology for 3D geomechanical model test of large underground houses[J].Chinese Journal of Rock Mechanics and Engineering,2003,22(9):1430-1436.
[17]李术才,周毅,李利平,等.地下工程流–固耦合模型试验新型相似材料的研制及应用[J].岩石力学与工程学报,2012,31(6):1128-1137.LI Shu-cai,ZHOU Yi,LI Li-ping,et al.Development and application of a new similar material for underground engineering fluid-solid coupling model test[J].Chinese Journal of Rock Mechanics and Engineering,2012,31(6):1128-1137.
[18]尹光志,李小双,魏作安,等.边坡和采场围岩变形破裂响应特征的相似模拟试验研究[J].岩石力学与工程学报,2011,30(增刊1):2913-2923.YIN Guang-zhi,LI Xiao-shuang,WEI Zuo-an,et al.Similar simulation study of deformation and failure response features of slope and stope rocks[J].Chinese Journal of Rock Mechanics and Engineering,2011,30(Supp.1):2913-2923.
[19]耿晓阳,张子新.砂岩相似材料制作方法研究[J].地下空间与工程学报,2015,11(1):23-28.GENG Xiao-yang,ZHANG Zi-xin.Study on preparation methods for similar materials of sandstone[J].Chinese Journal of Underground Space and Engineering,2015,11(1):23-28.
[20]况联飞,陈国舟,王涛.不同剪切模量砂岩的相似材料配比设计[J].地下空间与工程学报,2012,8(6):1173-1177.KUANG Lian-fei,CHEN Guo-zhou,WANG Tao.Mix design of similar materials for sandstones with different shear modulus[J].Chinese Journal of Underground Space and Engineering,2012,8(6):1173-1177.
[21]叶四桥.隧道洞口段落石灾害研究与防治[D].成都:西南交通大学,2008.YE Si-qiao.Research and mitigation of rockfall hazards at tunnel entrance and exit[D].Chengdu:Southwest Jiaotong University,2008.
[22]VIJAYAKUMAR S,YACOUB T,RANJRAM M,et al.Effect of rockfall shape on normal coefficient of restitution[C]//46th U.S.Rock Mechanics/Geomechanics Symposium.Illinois:[s.n.],2012.
[23]冯君,周德培,江南,等.顺层岩质边坡顺层滑动岩体范围分析[J].山地学报,2007,25(3):376-379.FENG Jun,ZHOU De-pei,JIANG Nan,et al.On the extent of bedding slipping rock mass of consequent rock slope[J].Journal of Mountain Science,2007,25(3):376-379.
[24]胡聪.高陡边坡危岩体失稳机理及其崩塌滚石运动规律[D].济南:山东大学,2014.HU Cong.Instability mechanism of high steep dangerous rock body and law of motion of rolling stones[D].Jinan:Shandong University,2014.
[25]GIANI G,GIACOMINI A,MIGLIAZZA M,et al.Experimental and theoretical studies to improve rock fall analysis and protection work design[J].Rock Mechanics and Rock Engineering,2004,37(5):369-389.
[26]黄润秋,刘卫华,周江平,等.滚石运动特征试验研究[J].岩土工程学报,2007,29(9):1296-1302.HUANG Run-qiu,LIU Wei-hua,ZHOU Jiang-ping,et al.Rolling tests on movement characteristics of rock blocks[J].Chinese Journal of Geotechnical Engineering,2007,29(9):1296-1302.
[27]USHIRO T,SHINOHARA S,TANIDA K,et al.A study on the motion of rockfalls on slopes[C]//Proceedings of5th Symposium on Impact Problems in Civil Engineering.[S.l.]:Japan Society of Civil Engineers,2000.
[28]章广成,唐辉明,向欣.冲击地面过程中落石特征参量的理论分析[J].岩石力学与工程学报,2012,31(增刊1):2839-2846.ZHANG Guang-cheng,TANG Hui-ming,XIANG Xin.Characteristic parameters theoretical analysis of rockfall impact on ground[J].Chinese Journal of Rock Mechanics and Engineering,2012,31(Supp.1):2839-2846.
[29]WONG R H,HO K W,CHAU K T.Shape and mechanical properties of slope material effects on the coefficient of restitution on rockfall study[C]//Proceedings of 4th North American Rock Mechanics Symposium.NARMS Seattle:[s.n.],2000.
[2]黄小福,张迎宾,赵兴权,等.地震条件下危岩崩塌运动特性的初步探讨[J].岩土力学,2017,38(2):583-592.HUANG Xiao-fu,ZHANG Ying-bin,ZHAO Xing-quan,et al.A preliminary study of kinetic characteristic of rock-fall under seismic loading[J].Rock and Soil Mechanics,2017,38(2):583-592.
[3]贾艳昌,谢谟文,昌圣翔,等.基于固有振动频率的滑移式和坠落式危岩块体稳定性评价模型研究[J].岩土力学,2017,38(7):2149-2156.JIA Yan-chang,XIE Mo-wen,CHANG Sheng-xiang,et al.A model for evaluation of stability of sliding-and falling-type dangerous rock blocks based on natural vibration frequency[J].Rock and Soil Mechanics,2017,38(7):2149-2156.
[4]CHAU K T,WONG R H C,WU J J.Coefficient of restitution and rotational motions of rockfall impacts[J].International Journal of Rock Mechanics and Mining Sciences,2002,39(1):69-77.
[5]WARREN DOUGLAS STEVENS.Rocfall:a tool for probabilistic analysis,design of remedial measures and prediction of rockfalls[D].Toronto:University of Toronto,1998.
[6]何思明,吴永,李新坡.滚石冲击碰撞恢复系数研究[J].岩土力学,2009,30(3):623-627.HE Si-ming,WU Yong,LI Xin-po.Research on restitution coefficient of rock fall[J].Rock and Soil Mechanics,2009,30(3):623-627.
[7]章广成,向欣,唐辉明.落石碰撞恢复系数的现场试验与数值计算[J].岩石力学与工程学报,2011,30(6):1266-1273.ZHANG Guang-cheng,XIANG Xin,TANG Hui-ming.Field test and numerical calculation of restitution coefficient of rockfall collision[J].Chinese Journal of Rock Mechanics and Engineering,2011,30(6):1266-1273.
[8]CHAU K T,WONG R H C,LIU J,et al.Shape effects on the coefficient of restitution during rockfall impacts[C]//Proceedings of 9th International Congress on Rock Mechanics,ISRM.Paris:[s.n.],1999.
[9]CHAU K T,WU J J,WONG R H,et al.The coefficient of restitution for boulders falling onto soil slopes with various values of dry density and water content[C]//Proc.Int.Symp.On Slope Stability Engineering:Geotechnical and Geoenvironmental Aspects.[S.l.]:[s.n.],1999.
[10]HEIDENREICH B,LABIOUSE V.Small-scale laboratory experiments of boulders bouncing on granular slopes[C]//Proceedings of 10th International Congress on Rock Mechanics,ISRM.Johannesburg:[s.n.],2003.
[11]LABIOUSE V,HEIDENREICH B.Half-scale experimental study of rockfall impacts on sandy slopes[J].Natural Hazards and Earth System Science,2009,9(6):1981-1993.
[12]PFEIFFER T J,BOWEN T D.Computer simulation of rockfalls[J].Bulletin of the Association of Engineering Geologists,1989,26(1):135-146.
[13]AGLIARDI F,CROSTA G B.High resolution three-dimensional numerical modelling of rockfalls[J].International Journal of Rock Mechanics and Mining Sciences,2003,40(4):455-471.
[14]GUZZETTI F,CROSTA G,DETTI R,et al.Stone:a computer program for the three-dimensional simulation of rock-falls[J].Computers&Geosciences,2002,28(9):1079-1093.
[15]姚文莉,岳嵘.有争议的碰撞恢复系数研究进展[J].振动与冲击,2015,34(19):43-48.YAO Wen-li,YUE Rong.Advance in controversial restitution coefficient study for impact problems[J].Journal of Vibration and Shock,2015,34(19):43-48.
[16]李仲奎,卢达溶,中山元,等.三维模型试验新技术及其在大型地下洞群研究中的应用[J].岩石力学与工程学报,2003,22(9):1430-1436.LI Zhong-kui,LU Da-rong,NAKAYAMA H,et al.Development and application of new technology for 3D geomechanical model test of large underground houses[J].Chinese Journal of Rock Mechanics and Engineering,2003,22(9):1430-1436.
[17]李术才,周毅,李利平,等.地下工程流–固耦合模型试验新型相似材料的研制及应用[J].岩石力学与工程学报,2012,31(6):1128-1137.LI Shu-cai,ZHOU Yi,LI Li-ping,et al.Development and application of a new similar material for underground engineering fluid-solid coupling model test[J].Chinese Journal of Rock Mechanics and Engineering,2012,31(6):1128-1137.
[18]尹光志,李小双,魏作安,等.边坡和采场围岩变形破裂响应特征的相似模拟试验研究[J].岩石力学与工程学报,2011,30(增刊1):2913-2923.YIN Guang-zhi,LI Xiao-shuang,WEI Zuo-an,et al.Similar simulation study of deformation and failure response features of slope and stope rocks[J].Chinese Journal of Rock Mechanics and Engineering,2011,30(Supp.1):2913-2923.
[19]耿晓阳,张子新.砂岩相似材料制作方法研究[J].地下空间与工程学报,2015,11(1):23-28.GENG Xiao-yang,ZHANG Zi-xin.Study on preparation methods for similar materials of sandstone[J].Chinese Journal of Underground Space and Engineering,2015,11(1):23-28.
[20]况联飞,陈国舟,王涛.不同剪切模量砂岩的相似材料配比设计[J].地下空间与工程学报,2012,8(6):1173-1177.KUANG Lian-fei,CHEN Guo-zhou,WANG Tao.Mix design of similar materials for sandstones with different shear modulus[J].Chinese Journal of Underground Space and Engineering,2012,8(6):1173-1177.
[21]叶四桥.隧道洞口段落石灾害研究与防治[D].成都:西南交通大学,2008.YE Si-qiao.Research and mitigation of rockfall hazards at tunnel entrance and exit[D].Chengdu:Southwest Jiaotong University,2008.
[22]VIJAYAKUMAR S,YACOUB T,RANJRAM M,et al.Effect of rockfall shape on normal coefficient of restitution[C]//46th U.S.Rock Mechanics/Geomechanics Symposium.Illinois:[s.n.],2012.
[23]冯君,周德培,江南,等.顺层岩质边坡顺层滑动岩体范围分析[J].山地学报,2007,25(3):376-379.FENG Jun,ZHOU De-pei,JIANG Nan,et al.On the extent of bedding slipping rock mass of consequent rock slope[J].Journal of Mountain Science,2007,25(3):376-379.
[24]胡聪.高陡边坡危岩体失稳机理及其崩塌滚石运动规律[D].济南:山东大学,2014.HU Cong.Instability mechanism of high steep dangerous rock body and law of motion of rolling stones[D].Jinan:Shandong University,2014.
[25]GIANI G,GIACOMINI A,MIGLIAZZA M,et al.Experimental and theoretical studies to improve rock fall analysis and protection work design[J].Rock Mechanics and Rock Engineering,2004,37(5):369-389.
[26]黄润秋,刘卫华,周江平,等.滚石运动特征试验研究[J].岩土工程学报,2007,29(9):1296-1302.HUANG Run-qiu,LIU Wei-hua,ZHOU Jiang-ping,et al.Rolling tests on movement characteristics of rock blocks[J].Chinese Journal of Geotechnical Engineering,2007,29(9):1296-1302.
[27]USHIRO T,SHINOHARA S,TANIDA K,et al.A study on the motion of rockfalls on slopes[C]//Proceedings of5th Symposium on Impact Problems in Civil Engineering.[S.l.]:Japan Society of Civil Engineers,2000.
[28]章广成,唐辉明,向欣.冲击地面过程中落石特征参量的理论分析[J].岩石力学与工程学报,2012,31(增刊1):2839-2846.ZHANG Guang-cheng,TANG Hui-ming,XIANG Xin.Characteristic parameters theoretical analysis of rockfall impact on ground[J].Chinese Journal of Rock Mechanics and Engineering,2012,31(Supp.1):2839-2846.
[29]WONG R H,HO K W,CHAU K T.Shape and mechanical properties of slope material effects on the coefficient of restitution on rockfall study[C]//Proceedings of 4th North American Rock Mechanics Symposium.NARMS Seattle:[s.n.],2000.