基于陈列柜边界条件的馆藏文物地震滑移响应试验
|
摘要
为保护馆藏浮放文物,采用振动台试验方法研究了地震作用下基于不同陈列柜边界条件下的文物滑移响应。根据展柜原型制作了1:1比例模型,分别考虑陈列柜底部浮放及固定于振动台面,进行了振动台试验。通过白噪声激励获得了两种边界条件下陈列柜的基频;通过对模型分别输入不同类型及不同强度的地震波,研究了地震作用下陈列柜及文物的震害形式,对比分析了两种边界条件下典型节点位移、加速度响应及动力放大系数。结果表明:无论陈列柜处于固定还是浮放状态,其基频远大于地震波卓越频率,因此震害较轻;对浮放文物而言,当地震波强度较小时,不同条件下文物的滑移响应为陈列柜浮放>陈列柜固定条件;当地震波强度较大时,由于陈列柜与振动台面的摩擦减震作用,文物的滑移响应为陈列柜浮放<陈列柜固定条件。为减小文物的滑移响应,陈列柜宜以浮放形式为主,并保持适当的间距。
Many museum pieces are of cultural heritage and worthy of protection for their historical and artistic values.Because such relics are usually free-standing,they are easily damaged during earthquakes.For example,the 2008 Wenchuan earthquake in China led to substantial losses of property such that at least 216 museums were affected,and more than 3169 cultural relics were damaged.Slide motion is a typical seismic response mode of museum cultural relics;large slide sizes may cause relics to drop from their display stands and incur damage.Thus,it is important to study slide response of free-standing cultural relics under earthquake conditions and adopt aseismic measures for protection.In previous works,theoretical analyses were mainly used to study the slide responses of free-standing relics.Experimental studies were insufficient,and boundary conditions of showcases were seldom considered.To determine protection measures for movable cultural relics,slide responses of free-standing cultural museum relics under earthquake conditions are studied by considering various showcase boundary conditions.1:1 scale models were created on the basis of actual of a museum showcase sizes.A glass cultural relic was placed in the showcase by free-standing mode.The static friction coefficient between the relic bottom and its base was determined to be μ = 0.15 and the barycenter height values of the showcase and relic were calculated as 556 mm and 65 mm,respectively.To study seismic responses of the relic,acceleration sensors were set on the showcase bottom and relic top.In addition,a video admeasuring apparatus was used to capture displacement response values of the relic.Shaking table tests were conducted that considered two boundary conditions of the showcase bottom including fixed and free-standing status.Frequency distributions of the showcase under both boundary conditions were obtained by white noise excitation.Three different types of earthquake waves including those of El-Centro in 1940 and Taft and Artificial of Ⅱ site classification were applied to the models in east-west direction with intensities of PGA = 0.1g,0.2 g,0.4 g,and 0.7 g;time duration of 30 s;and time space of 0.02 s.Aseismic parameters such as displacement,acceleration,and dynamic magnification coefficients for both relic and showcase under the various boundary conditions were compared.Results show that under both showcase boundary conditions,relic sliding was minimal under small-intensity earthquake conditions,while the sliding was obvious under those of high intensity.For the duration of the tests,the relic slid under both showcase boundary conditions,and the showcase slid only under free-standing showcase boundary conditions.When earthquake intensity increased to certain degree,slide motion of the relic under fixed showcase boundary condition increased to a more significant degree than that under free-standing showcase boundary conditions.Regardless of showcase status,the prominent frequency factors were far greater than those of the input earthquake waves;thus,the showcase was not damaged significantly.The slide response for the relic under the free-standing showcase boundary condition was more significant under low-intensity earthquakes than that under fixed conditions and was significantly less when earthquake intensity increased,obviously due to friction between the showcase and shaking table.Thus,free-standing museum showcases are helpful for mitigating the slide response of cultural relic contained in them,provided that the distance between each showcase is sufficient to guarantee sliding motion during strong earthquakes.
Many museum pieces are of cultural heritage and worthy of protection for their historical and artistic values.Because such relics are usually free-standing,they are easily damaged during earthquakes.For example,the 2008 Wenchuan earthquake in China led to substantial losses of property such that at least 216 museums were affected,and more than 3169 cultural relics were damaged.Slide motion is a typical seismic response mode of museum cultural relics;large slide sizes may cause relics to drop from their display stands and incur damage.Thus,it is important to study slide response of free-standing cultural relics under earthquake conditions and adopt aseismic measures for protection.In previous works,theoretical analyses were mainly used to study the slide responses of free-standing relics.Experimental studies were insufficient,and boundary conditions of showcases were seldom considered.To determine protection measures for movable cultural relics,slide responses of free-standing cultural museum relics under earthquake conditions are studied by considering various showcase boundary conditions.1:1 scale models were created on the basis of actual of a museum showcase sizes.A glass cultural relic was placed in the showcase by free-standing mode.The static friction coefficient between the relic bottom and its base was determined to be μ = 0.15 and the barycenter height values of the showcase and relic were calculated as 556 mm and 65 mm,respectively.To study seismic responses of the relic,acceleration sensors were set on the showcase bottom and relic top.In addition,a video admeasuring apparatus was used to capture displacement response values of the relic.Shaking table tests were conducted that considered two boundary conditions of the showcase bottom including fixed and free-standing status.Frequency distributions of the showcase under both boundary conditions were obtained by white noise excitation.Three different types of earthquake waves including those of El-Centro in 1940 and Taft and Artificial of Ⅱ site classification were applied to the models in east-west direction with intensities of PGA = 0.1g,0.2 g,0.4 g,and 0.7 g;time duration of 30 s;and time space of 0.02 s.Aseismic parameters such as displacement,acceleration,and dynamic magnification coefficients for both relic and showcase under the various boundary conditions were compared.Results show that under both showcase boundary conditions,relic sliding was minimal under small-intensity earthquake conditions,while the sliding was obvious under those of high intensity.For the duration of the tests,the relic slid under both showcase boundary conditions,and the showcase slid only under free-standing showcase boundary conditions.When earthquake intensity increased to certain degree,slide motion of the relic under fixed showcase boundary condition increased to a more significant degree than that under free-standing showcase boundary conditions.Regardless of showcase status,the prominent frequency factors were far greater than those of the input earthquake waves;thus,the showcase was not damaged significantly.The slide response for the relic under the free-standing showcase boundary condition was more significant under low-intensity earthquakes than that under fixed conditions and was significantly less when earthquake intensity increased,obviously due to friction between the showcase and shaking table.Thus,free-standing museum showcases are helpful for mitigating the slide response of cultural relic contained in them,provided that the distance between each showcase is sufficient to guarantee sliding motion during strong earthquakes.
引文
[1]Anne C,Debra F L,Mairead F.Sample Preparation and Tes-ting Methods for the Evaluation of Microcrystalline Waxes forthe Seismic Protection of Art Objects[J].Journal of Testingand Evaluation,2008,36(1):24-33.
[2]Mustafa E,Eser D,Nevra E,et al.Earthquake risk mitiga-tion in Istanbul museums[J].Nat Hazards,2010,53:97-108.
[3]周乾,闫维明.汶川地震可移动文物震害研究[J].文物保护与考古科学,2010,22(3):36-43.ZHOU Qian,YAN Wei-ming.Analysis of Damage to Free-standing Cultural Relics Caused by the Wenchuan Earthquake[J].Sciences of Conservation and Archaeology,2010,22(3):36-43.
[4]韦荃,陈显丹.5.12汶川大地震对四川可移动文物的损坏与启示[J].四川文物,2008,(4):10-13.WEI Quan,CHEN Xian-dan.Experiences from Damages ofMovable Cultural Relics by Wenchuan Earthquake on May12th,2008[J].Sichuan Cultural Relics,2008,(4):10-13.
[5]黄永林,杨伟林,章熙海.地震作用下浮放物体的运动研究[J].地震学刊,1994,(3):1-5.HUANG Yong-lin,YANG Wei-lin,ZHANG Xi-hai.Study onMotion of Free-standing Body Excited by Earthquake[J].Journal of Seismology,1994,(3):1-5.
[6]王云剑,陈汝斌.浮放设备抗震技术标准[A]//王亚勇,李爱群.现代地震工程进展[G].南京:东南大学出版社,2002:932-936.WANG Yun-jian,CHEN Ru-bin.Aseismic TechnologyStandard for Free-standing Equipments[A]//WANG Ya-yong,LI Ai-qun:Development of Modern Seismic Engineering[G].Nanjing:Southeast University Press,2002:932-936.
[7]郭恩栋,吴伟,胡煜文,等.浮放设备地震滑移反应数值模拟研究[J].地震工程与工程振动,2007,27(6):124-129.GUO En-dong,WU Wei,HU Yu-wen,et al.NumericalStudy on Seismic Response of Free-standing Equipment.Jour-nal of Earthquake Engineering and Engineering Vibration[J].2007,27(6):124-129.
[8]Harry W S,Nicholas P J.Base Excitation of Rigid Bodies.Ⅰ:Formulation[J].Journal of Engineering Mechanics,1991,117(10):2286-2306.
[9]Harry W S,Nicholas P J.Base Excitation of Rigid Bodies.Ⅱ:Periodic Slide-rock Response[J].Journal of EngineeringMechanics,1991,117(10):2307-2328.
[10]Harry W S.Criteria for Initiation of Slide,Rock,and Slide-rock Rigid Body Modes[J].Journal of Engineering Mechan-ics,1996,122(7):690-693.
[11]施卫星,刘凯雁,王立志.网架减震球型钢支座减震性能振动台试验研究[J].西北地震学报,2009,31(4):344-348.SHI Wei-xing,LIU Kai-yan,WANG Li-zhi.Shaking TableTest Study on Damping Performance of Steel Ball-bearing forGrid Structure[J].Northwestern Seismological Journal,2009,31(4):344-348.
[12]石玉成,李舒,刘琨.地震作用下骆驼城土遗址的安全性评价[J].西北地震学报,2011,33(3):255-260.SHI Yu-cheng,LI Shu,LIU Kun.Safety Evaluation of theCamel Town Soil Relics under Earthquake Action[J].North-western Seismological Journal,2011,33(3):255-260.
[13]吴小峰,孙启国,狄杰建,等.抗震分析反应谱法和时程分析法数值仿真比较[J].西北地震学报,2011,33(3):275-278.WU Xiao-feng,SUN Qi-guo,DI Jie-jian,et al.A NumericalSimulation Comparison between Response Spectrum Analysisand Time History Analysis[J].Northwestern SeismologicalJournal,2011,33(3):275-278.
[14]周乾,闫维明,纪金豹.基于陈列柜边界条件的馆藏文物摇晃响应试验[J].土木工程与管理学报,2011,28(3):401-406.ZHOU Qian,YAN Wei-ming,JI Jin-bao.Experiments onOscillation Response of Museum Cultural Relics under Earth-quakes Considering Different Showcase Boundary Conditions[J].Journal of Civil Engineering and Management,2011,28(3):401-406.
[15]Zhou Q,Yan W M.Sliding Response of Free-standing Cul-tural Relics under Earthquakes by Simulation[J].AdvancedMaterials Research,2011,163-167:2142-2146.
[16]Zhou Q,Yan W M.Simulation of Oscillation Response ofFree-standing Object under Earthquakes[J].Applied Me-chanics and Materials,2012,105-107:417-422.
[2]Mustafa E,Eser D,Nevra E,et al.Earthquake risk mitiga-tion in Istanbul museums[J].Nat Hazards,2010,53:97-108.
[3]周乾,闫维明.汶川地震可移动文物震害研究[J].文物保护与考古科学,2010,22(3):36-43.ZHOU Qian,YAN Wei-ming.Analysis of Damage to Free-standing Cultural Relics Caused by the Wenchuan Earthquake[J].Sciences of Conservation and Archaeology,2010,22(3):36-43.
[4]韦荃,陈显丹.5.12汶川大地震对四川可移动文物的损坏与启示[J].四川文物,2008,(4):10-13.WEI Quan,CHEN Xian-dan.Experiences from Damages ofMovable Cultural Relics by Wenchuan Earthquake on May12th,2008[J].Sichuan Cultural Relics,2008,(4):10-13.
[5]黄永林,杨伟林,章熙海.地震作用下浮放物体的运动研究[J].地震学刊,1994,(3):1-5.HUANG Yong-lin,YANG Wei-lin,ZHANG Xi-hai.Study onMotion of Free-standing Body Excited by Earthquake[J].Journal of Seismology,1994,(3):1-5.
[6]王云剑,陈汝斌.浮放设备抗震技术标准[A]//王亚勇,李爱群.现代地震工程进展[G].南京:东南大学出版社,2002:932-936.WANG Yun-jian,CHEN Ru-bin.Aseismic TechnologyStandard for Free-standing Equipments[A]//WANG Ya-yong,LI Ai-qun:Development of Modern Seismic Engineering[G].Nanjing:Southeast University Press,2002:932-936.
[7]郭恩栋,吴伟,胡煜文,等.浮放设备地震滑移反应数值模拟研究[J].地震工程与工程振动,2007,27(6):124-129.GUO En-dong,WU Wei,HU Yu-wen,et al.NumericalStudy on Seismic Response of Free-standing Equipment.Jour-nal of Earthquake Engineering and Engineering Vibration[J].2007,27(6):124-129.
[8]Harry W S,Nicholas P J.Base Excitation of Rigid Bodies.Ⅰ:Formulation[J].Journal of Engineering Mechanics,1991,117(10):2286-2306.
[9]Harry W S,Nicholas P J.Base Excitation of Rigid Bodies.Ⅱ:Periodic Slide-rock Response[J].Journal of EngineeringMechanics,1991,117(10):2307-2328.
[10]Harry W S.Criteria for Initiation of Slide,Rock,and Slide-rock Rigid Body Modes[J].Journal of Engineering Mechan-ics,1996,122(7):690-693.
[11]施卫星,刘凯雁,王立志.网架减震球型钢支座减震性能振动台试验研究[J].西北地震学报,2009,31(4):344-348.SHI Wei-xing,LIU Kai-yan,WANG Li-zhi.Shaking TableTest Study on Damping Performance of Steel Ball-bearing forGrid Structure[J].Northwestern Seismological Journal,2009,31(4):344-348.
[12]石玉成,李舒,刘琨.地震作用下骆驼城土遗址的安全性评价[J].西北地震学报,2011,33(3):255-260.SHI Yu-cheng,LI Shu,LIU Kun.Safety Evaluation of theCamel Town Soil Relics under Earthquake Action[J].North-western Seismological Journal,2011,33(3):255-260.
[13]吴小峰,孙启国,狄杰建,等.抗震分析反应谱法和时程分析法数值仿真比较[J].西北地震学报,2011,33(3):275-278.WU Xiao-feng,SUN Qi-guo,DI Jie-jian,et al.A NumericalSimulation Comparison between Response Spectrum Analysisand Time History Analysis[J].Northwestern SeismologicalJournal,2011,33(3):275-278.
[14]周乾,闫维明,纪金豹.基于陈列柜边界条件的馆藏文物摇晃响应试验[J].土木工程与管理学报,2011,28(3):401-406.ZHOU Qian,YAN Wei-ming,JI Jin-bao.Experiments onOscillation Response of Museum Cultural Relics under Earth-quakes Considering Different Showcase Boundary Conditions[J].Journal of Civil Engineering and Management,2011,28(3):401-406.
[15]Zhou Q,Yan W M.Sliding Response of Free-standing Cul-tural Relics under Earthquakes by Simulation[J].AdvancedMaterials Research,2011,163-167:2142-2146.
[16]Zhou Q,Yan W M.Simulation of Oscillation Response ofFree-standing Object under Earthquakes[J].Applied Me-chanics and Materials,2012,105-107:417-422.
版权所有：© 2023 中国地质图书馆 中国地质调查局地学文献中心