基于自由落体的落石冲击土层的理论及LS-DYNA模拟研究
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摘要
通过理论推导,分别获得了滚石最大冲击力的脉冲算法、弹塑性算法,采用LS-DYNA软件研究了滚石冲击过程中的冲击力及侵彻深度随冲击时间的变化规律,并结合具体算例对滚石冲击力的Hertz算法、日本算法、瑞士算法、关宝树算法、隧道手册算法、脉冲算法、弹塑性算法及数值模拟结果进行了对比分析,研究得出:LS-DYNA数值模拟结果、日本算法、瑞士算法、弹塑性算法及脉冲算法一致性较好,但脉冲算法所得出的计算结果略微偏小.然后以数值模拟结果及隧道手册算法结果为基础,建立了滚石的冲击力的冲击速度与放大系数的关系曲线,并同时考虑了滚石冲击过程中的恢复系数、冲击角度及滚石重力所带来的影响,从而得出了最终滚石冲击力的LS-DYNA算法,并验证了其适用性.
By means of theoretical derivation,the impulse algorithm and elastic-plastic algorithm for the maximum impact force of rockfall are obtained.The change rules of impact force and penetration depth along with impact time in the process of rockfall impact are studied by using LSDYNA software.The results of Hertz algorithm,Japanese algorithm,Swiss algorithm,Guan Baoshu algorithm,tunnel manual algorithm,impulse algorithm,elastic-plastic algorithm and numerical simulation results of the rockfall impact force are compared and analyzed with specific examples.The conclusions drawn show that LS-DYNA numerical simulation results,Japanese algorithm,Swiss algorithm,elastic-plastic algorithm and impulse algorithm have better consistency,but the results of impulse algorithm are slightly smaller.Based on the numerical simulation results and the results of tunnel manual algorithm,the relation curve of impact velocity and magnification factor of rockfall is established,with the effects of the recovery factor,the impact angle and the gravity of the rockfall on the impact force taken into account.Therefore,the LS-DYNA algorithm for calculating the final impact force of rockfall is obtained and its applicability is verified.
By means of theoretical derivation,the impulse algorithm and elastic-plastic algorithm for the maximum impact force of rockfall are obtained.The change rules of impact force and penetration depth along with impact time in the process of rockfall impact are studied by using LSDYNA software.The results of Hertz algorithm,Japanese algorithm,Swiss algorithm,Guan Baoshu algorithm,tunnel manual algorithm,impulse algorithm,elastic-plastic algorithm and numerical simulation results of the rockfall impact force are compared and analyzed with specific examples.The conclusions drawn show that LS-DYNA numerical simulation results,Japanese algorithm,Swiss algorithm,elastic-plastic algorithm and impulse algorithm have better consistency,but the results of impulse algorithm are slightly smaller.Based on the numerical simulation results and the results of tunnel manual algorithm,the relation curve of impact velocity and magnification factor of rockfall is established,with the effects of the recovery factor,the impact angle and the gravity of the rockfall on the impact force taken into account.Therefore,the LS-DYNA algorithm for calculating the final impact force of rockfall is obtained and its applicability is verified.
引文
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[20]叶四桥，陈洪凯，唐红梅．落石冲击力计算方法[J]．中国铁道科学，2010,31(6):56-62.YE Siqiao,CHEN Hongkai,TANG Hongmei.The calculation method for the impact force of the rockfall[J].China Railway Science,2010,31(6):56-62.(in Chinese)
[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 Siqiao.Research and mitigation of rockfall hazards at tunnel entrance and exit[D].Chengdu:Southwest Jiaotong University,2008.(in Chinese)
[22]叶四桥，陈洪凯，唐红梅．落石冲击力计算方法的比较研究[J]．水文地质工程地质，2010,37(2):59-64.YE Siqiao,CHEN Hongkai,TANG Hongmei.Comparative research on impact force calculation methods for rockfalls[J]. Hydrogeology&Engineering Geology,2010,37(2):59-64.(in Chinese)
[2]THORNTON C,NING Z M.A theoretical model for the stick/bounce behaviour of adhesive,elastic-plastic spheres[J].Powder Technology,1998,99(2):154-162.
[3]JOHNSON H L.Contact mechanics[M].Cambridge:Cambridge University Press,1985.
[4]KAWAHARA S,MURO T.Effects of dry density and thickness of sandy soil on impact response due to rockfall[J].Journal of Terramechanics,2006,43(3):329-340.
[5]LABIOUSE V,DESCOEUDRES F,MONTANI S.Experimental study of rock sheds impacted by rock blocks[J].Structural Engineering International,1996,6(3):171-176.
[6]PICHLER B,HELLMICH C,MANG H A.Impact of rocks onto gravel design and evaluation of experiments[J].International Journal of Impact Engineering,2005,31(5):559-578.
[7]MOUGIN J P,PERROTIN P,MOMMESSIN M,et al.Rock fall impact on reinforced concrete slab:an experimental approach[J].International Journal of Impact Engineering,2005,31(2):169-183.
[8]YU B,YI W,ZHAO H B.Experimental study on the maximum impact force by rock fall[J].Landslides,2018,15(2):233-242.
[9]AZZONI A,BARBERA G L,ZANINETTI A.Analysis and prediction of rockfalls using a mathematical model[J].International Journal of Rock Mechanics and Mining Sciences&Geomechanics Abstracts,1995,32(7):709-724.
[10]WANG X,XIA Y X,ZHOU T Y.Theoretical analysis of rockfall impacts on the soil cushion layer of protective structures[J]. Advances in Civil Engineering,2018(2):1-18.
[11]杨其新，关宝树．落石冲击力计算方法的试验研究[J]．铁道学报，1996,18(1):101-106.YANG Qixin,GUAN Baoshu.Test and research on calculating method of falling stone impulsive force[J].Journal of the China Railway Society,1996,18(1):101-106.(in Chinese)
[12]廖朝华，郭小红．公路隧道设计手册[M]．北京：人民交通出版社，2012.LIAO Chaohua,GUO Xiaohong.Manual for design of highway tunnel[M].Beijing:China Communications Press,2012.(in Chinese)
[13]向波，何思明，庄卫林，等．滚石冲击荷载下垫层材料的动力响应研究[J]．公路交通科技，2015,32(1):45-49,56.XIANG Bo,HE Siming,ZHUANG Weilin,et al.Research on dynamic response of cushion under rockfall impact[J].Journal of Highway and Transportation Research and Development,2015,32(1):45-49,56.(in Chinese)
[14]周晓宇，陈艾荣，马如进．滚石柔性防护网耗能规律数值模拟[J]．长安大学学报（自然科学版），2012,32(6):59-66.ZHOU Xiaoyu,CHEN Airong,MA Rujin.Numerical simulation of energy dissipation mechanism on falling rocks protection nets[J].Journal of Chang’an University(Natural Science Edition),2012,32(6):59-66.(in Chinese)
[15]王永东，周天跃，柴伦磊，等．基于能量分析的落石对棚洞垫层冲击力学研究[J]．地下空间与工程学报，2018,14（增1):148-153.WANG Yongdong,ZHOU Tianyue,CHAI Lunlei,et al.Impact mechanics of rock-fall to shed cushion based on energy analysis[J].Chinese Journal of Underground Space and Engineering,2018,14(S1):148-153.(in Chinese)
[16]何思明，沈均，罗渝，等．滚石坡面法向冲击动力响应特性研究[J]．工程力学，2011,28(6):118-124.HE Siming,SHEN Jun,LUO Yu,et al.Study on the characteristics of normal impact of post-earthquake rock-fall on slope[J].Engineering Mechanics,2011,28(6):118-124.(in Chinese)
[17]袁进科，黄润秋，裴向军．滚石冲击力测试研究[J]．岩土力学，2014,35(1):48-54.YUAN Jinke,HUANG Runqiu,PEI Xiangjun.Tes tresearch on rockfall impact force[J].Rock and Soil Mechanics,2014,35(1):48-54.(in Chinese)
[18]刘茂．基于弹塑性修正Hertz接触理论的落石冲击力计算方法[J]．中国地质灾害与防治学报，2012,23(3):21-27.LIU Mao.Calculation of impact force of falling rock based on elastoplastic modified Hertz contact theory[J].The Chinese Journal of Geological Hazard and Control,2012,23(3):21-27.(in Chinese)
[19]BRIZMER V,KLIGERMAN Y,ETSION I.The effect of contact conditions and material properties on the elasticity terminus of a spherical contact[J].International Journal of Solids and Structures,2006,43(18/19):5736-5749.
[20]叶四桥，陈洪凯，唐红梅．落石冲击力计算方法[J]．中国铁道科学，2010,31(6):56-62.YE Siqiao,CHEN Hongkai,TANG Hongmei.The calculation method for the impact force of the rockfall[J].China Railway Science,2010,31(6):56-62.(in Chinese)
[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 Siqiao.Research and mitigation of rockfall hazards at tunnel entrance and exit[D].Chengdu:Southwest Jiaotong University,2008.(in Chinese)
[22]叶四桥，陈洪凯，唐红梅．落石冲击力计算方法的比较研究[J]．水文地质工程地质，2010,37(2):59-64.YE Siqiao,CHEN Hongkai,TANG Hongmei.Comparative research on impact force calculation methods for rockfalls[J]. Hydrogeology&Engineering Geology,2010,37(2):59-64.(in Chinese)