汶川8.0级地震液化特征初步研究
|
摘要
针对目前对汶川8.0级地震液化认识尚少的现状,通过较详尽的现场调查以及相关水文、地质资料分析和现场勘察,讨论本次地震的液化分布及特征问题。研究结果表明,本次地震液化范围广,涉及长约500 km、宽约200 km的区域,但分布很不均匀。液化集中在长约160 km、宽约60 km的长方形区域并呈6个条带分布,在VIII度区内最为集中,与各地区的区域水文地质和工程地质条件呈良好的对应关系。通过调查和分析,发现本次地震液化具有与以往不同的3个突出特征:(1)VI度区内出现显著液化及其震害现象,实地发现10处液化点,分布在5个不同地区,其中有2处液化直接导致了房屋的破坏;(2)深层土液化,4个不同地区的村庄均出现了液化喷水高度达10 m以上,专门的勘察确认了此次地震20 m处液化的真实性;(3)砂砾层液化,专门的勘察验证这一现象,并且通过液化喷砂量和喷水时间以及工程地质资料的综合分析,推断此次地震中砂砾层液化应占很大比重。
Considering the limited knowledge on the liquefaction behaviors in the Wenchuan 8.0 earthquake,the liquefaction characteristics are discussed through detailed site investigation and analyses of corresponding hydrological,geologic and in-situ tests for the specific sites.The analytical results indicate that the distribution of the liquefaction phenomena in the event is vast with the region covered by length of 500 km and width of 200 km,but the liquefaction distribution is rather nonuniform.The liquefaction is mainly located in the area of a rectangle with 160 km in length and 60 km in width;and it is distributed principally in the 6 belts,which are consistent with the local hydrological and geotechnical conditions.Moreover,three salient characteristics of the liquefaction behaviors that are different from the previous earthquakes are discovered by the investigation.It is shown that:(1) Liquefaction phenomena are observed within the regions of seismic zone with intensity VI,which has not been documented previously in Mainland of China.10 such liquefaction sites in 5 different areas are confirmed and in 2 liquefaction sites among which the buildings are damaged directly due to the liquefaction.(2) The liquefaction phenomena in deep soils,i.e.more than 20 m in depth,occur in the shock,and the macrophenomena of more than 10 m water ejection in 4 different villages are observed;and the in-situ tests for the specific sites verify the judgment.(3) The characteristics show that the gravel soils liquefy in the shock;and the in-situ tests for the specific sites verify the reality of such behaviors.Also the synthetic analyses of sand ejection,duration of waterspout and corresponding geotechnical information all demonstrate that the gravel soil liquefaction behaviors are considerable in this earthquake.
Considering the limited knowledge on the liquefaction behaviors in the Wenchuan 8.0 earthquake,the liquefaction characteristics are discussed through detailed site investigation and analyses of corresponding hydrological,geologic and in-situ tests for the specific sites.The analytical results indicate that the distribution of the liquefaction phenomena in the event is vast with the region covered by length of 500 km and width of 200 km,but the liquefaction distribution is rather nonuniform.The liquefaction is mainly located in the area of a rectangle with 160 km in length and 60 km in width;and it is distributed principally in the 6 belts,which are consistent with the local hydrological and geotechnical conditions.Moreover,three salient characteristics of the liquefaction behaviors that are different from the previous earthquakes are discovered by the investigation.It is shown that:(1) Liquefaction phenomena are observed within the regions of seismic zone with intensity VI,which has not been documented previously in Mainland of China.10 such liquefaction sites in 5 different areas are confirmed and in 2 liquefaction sites among which the buildings are damaged directly due to the liquefaction.(2) The liquefaction phenomena in deep soils,i.e.more than 20 m in depth,occur in the shock,and the macrophenomena of more than 10 m water ejection in 4 different villages are observed;and the in-situ tests for the specific sites verify the judgment.(3) The characteristics show that the gravel soils liquefy in the shock;and the in-situ tests for the specific sites verify the reality of such behaviors.Also the synthetic analyses of sand ejection,duration of waterspout and corresponding geotechnical information all demonstrate that the gravel soil liquefaction behaviors are considerable in this earthquake.
引文
[1]SEED H B,IDRISS I M.Simplified procedure for evaluating soil liquefaction potential[J].Journal of the Soil Mechanics and Foundation Division,ASCE,1971,97(SM9):1 249–1 273.
[2]SEED R B,CETIN K O,MOSS R E S,et al.Recent advances in soil liquefaction engineering,a unified and consistent framework[R].EERC,USA:Earthquake Engineering Research Center,2003.
[3]KU C S,LEE D H,WU J H.Evaluation of soil liquefaction in the Chi-Chi Taiwan earthquake using CPT[J].Soil Dynamics and Earthquake Engineering,2004,24(9/10):659–673.
[4]孟祥跃,张均锋,谈庆明,等.冲击载荷下饱和砂土中流动和破坏的X光观测[J].岩石力学与工程学报,2002,21(6):803–807.(MENG Xiangyue,ZHANG Junfeng,TAN Qingming,et al.X-ray observation on flow and failure of saturated sand under impact loading[J].Chinese Journal of Rock Mechanics and Engineering,2002,21(6):803–807.(in Chinese))
[5]王汝恒,贾彬,邓安福,等.砂卵石土动力特性的动三轴试验研究[J].岩石力学与工程学报,2006,25(增2):4 059–4 064.(WANG Ruheng,JIA Bin,DENG Anfu,et al.Dynamic triaxial testing study on dynamic characteristics of sandy pebble soil[J].Chinese Journal of Rock Mechanics and Engineering,2006,25(Supp.2):4 059–4 064.(in Chinese))
[6]刘小丽,刘红军,贾永刚.黄河三角洲饱和粉土层地震液化判别方法及液化特征研究[J].岩石力学与工程学报,2007,26(增1):2 981–2 987.(LIU Xiaoli,LIU HongjunJ,IA Yonggang.Investigation on prediction methods and characteristics of earthquake-induced liquefaction of silty soil in the Yellow River delta[J].Chinese Journal of Rock Mechanics and Engineering,2007,26(Supp.1):2 981–2 987.(in Chinese))
[7]中国科学院工程力学研究所.海城地震震害[M].北京:地震出版社,1979.(Institute of Engineering Mechanics,Chinese Academy of Sciences.Haicheng earthquake-induced damages[M].Beijing:Earthquake Press,1979.(in Chinese))
[8]刘恢先.唐山大地震震害[M].北京:地震出版社,1989.(LIU Huixian.The Tangshan great earthquake in 1976[M].Beijing:Earthquake Press,1989.(in Chinese))
[9]刘惠珊.1995年阪神大地震的液化特点[J].工程抗震,2001,(1):22–26.(LIU Huishan.Some features of liquefaction during the 1995 great Hanshin-Awaji earthquake[J].Earthquake Resistant Engineering,2001,(1):22–26.(in Chinese))
[10]胡聿贤.地震工程学[M].北京:地震出版社,1988.(HU Yuxian.Earthquake engineering[M].Beijing:Earthquake Press,1988.(in Chinese))
[11]廖振鹏.地震小区划(理论与实践)[M].北京:地震出版社,1989.(LIAO Zhenpeng.Seismic microzonation(theory and practice)[M].Beijing:Earthquake Press,1989.(in Chinese))
[12]范士凯,粟怡然.砂土液化的工程地质判别法[J].资源环境与工程,2006,20(增1):595–600.(FAN Shikai,SU Yiran.The engineering geological discrimination for soil liquefaction[J].Resources Environment and Engineering,2006,20(Supp.1):595–600.(in Chinese))
[13]中华人民共和国国家标准编写组.GB50011–2001建筑抗震设计规范[S].北京:中国建筑工业出版社,2001.(The National Standards Compilation Group of People′s Republic of China.GB50011–2001 Code for seismic design of buildings[S].Beijing:China Architecture and Building Press,2001.(in Chinese))
[14]GONZALEZ L,ABDOUM T.Physical modeling and visualization of soil liquefaction under high confining stress[J].Journal of Earthquake Engineering and Engineering Vibration,2005,4(1):47–56.
[15]何银武.论成都盆地的成生时代及其早期沉积物的一般特征[J].地质论评,1992,38(2):149–156.(HE Yinwu.The age of formation of Chengdu Basin and features of its early deposits[J].Geological Review,1992,38(2):149–156.(in Chinese))
[16]YOUD T L,IDRISS I M.Liquefaction resistance of soils:summary report from the 1996 NCEER and 1998 NCEER/NSF workshops on evaluation of liquefaction resistance of soils[J].Journal of Geotechnical and Geoenvironment Engineering,2001,127(4):297–313.
[2]SEED R B,CETIN K O,MOSS R E S,et al.Recent advances in soil liquefaction engineering,a unified and consistent framework[R].EERC,USA:Earthquake Engineering Research Center,2003.
[3]KU C S,LEE D H,WU J H.Evaluation of soil liquefaction in the Chi-Chi Taiwan earthquake using CPT[J].Soil Dynamics and Earthquake Engineering,2004,24(9/10):659–673.
[4]孟祥跃,张均锋,谈庆明,等.冲击载荷下饱和砂土中流动和破坏的X光观测[J].岩石力学与工程学报,2002,21(6):803–807.(MENG Xiangyue,ZHANG Junfeng,TAN Qingming,et al.X-ray observation on flow and failure of saturated sand under impact loading[J].Chinese Journal of Rock Mechanics and Engineering,2002,21(6):803–807.(in Chinese))
[5]王汝恒,贾彬,邓安福,等.砂卵石土动力特性的动三轴试验研究[J].岩石力学与工程学报,2006,25(增2):4 059–4 064.(WANG Ruheng,JIA Bin,DENG Anfu,et al.Dynamic triaxial testing study on dynamic characteristics of sandy pebble soil[J].Chinese Journal of Rock Mechanics and Engineering,2006,25(Supp.2):4 059–4 064.(in Chinese))
[6]刘小丽,刘红军,贾永刚.黄河三角洲饱和粉土层地震液化判别方法及液化特征研究[J].岩石力学与工程学报,2007,26(增1):2 981–2 987.(LIU Xiaoli,LIU HongjunJ,IA Yonggang.Investigation on prediction methods and characteristics of earthquake-induced liquefaction of silty soil in the Yellow River delta[J].Chinese Journal of Rock Mechanics and Engineering,2007,26(Supp.1):2 981–2 987.(in Chinese))
[7]中国科学院工程力学研究所.海城地震震害[M].北京:地震出版社,1979.(Institute of Engineering Mechanics,Chinese Academy of Sciences.Haicheng earthquake-induced damages[M].Beijing:Earthquake Press,1979.(in Chinese))
[8]刘恢先.唐山大地震震害[M].北京:地震出版社,1989.(LIU Huixian.The Tangshan great earthquake in 1976[M].Beijing:Earthquake Press,1989.(in Chinese))
[9]刘惠珊.1995年阪神大地震的液化特点[J].工程抗震,2001,(1):22–26.(LIU Huishan.Some features of liquefaction during the 1995 great Hanshin-Awaji earthquake[J].Earthquake Resistant Engineering,2001,(1):22–26.(in Chinese))
[10]胡聿贤.地震工程学[M].北京:地震出版社,1988.(HU Yuxian.Earthquake engineering[M].Beijing:Earthquake Press,1988.(in Chinese))
[11]廖振鹏.地震小区划(理论与实践)[M].北京:地震出版社,1989.(LIAO Zhenpeng.Seismic microzonation(theory and practice)[M].Beijing:Earthquake Press,1989.(in Chinese))
[12]范士凯,粟怡然.砂土液化的工程地质判别法[J].资源环境与工程,2006,20(增1):595–600.(FAN Shikai,SU Yiran.The engineering geological discrimination for soil liquefaction[J].Resources Environment and Engineering,2006,20(Supp.1):595–600.(in Chinese))
[13]中华人民共和国国家标准编写组.GB50011–2001建筑抗震设计规范[S].北京:中国建筑工业出版社,2001.(The National Standards Compilation Group of People′s Republic of China.GB50011–2001 Code for seismic design of buildings[S].Beijing:China Architecture and Building Press,2001.(in Chinese))
[14]GONZALEZ L,ABDOUM T.Physical modeling and visualization of soil liquefaction under high confining stress[J].Journal of Earthquake Engineering and Engineering Vibration,2005,4(1):47–56.
[15]何银武.论成都盆地的成生时代及其早期沉积物的一般特征[J].地质论评,1992,38(2):149–156.(HE Yinwu.The age of formation of Chengdu Basin and features of its early deposits[J].Geological Review,1992,38(2):149–156.(in Chinese))
[16]YOUD T L,IDRISS I M.Liquefaction resistance of soils:summary report from the 1996 NCEER and 1998 NCEER/NSF workshops on evaluation of liquefaction resistance of soils[J].Journal of Geotechnical and Geoenvironment Engineering,2001,127(4):297–313.
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