青藏铁路沿线冻土场地地震动特征研究
摘要
基于对青藏铁路沿线多年冻土区的现场地质考察、14个典型钻孔的地质编录以及现场测试,获取了青藏铁路沿线多年冻土区土层波速的基本特征。而后结合室内动三轴有关冻土动强度的试验结果,使用该地区50a超越概率为62.5%,10.0%和2.0%的人造基岩地震波输入,通过土层地震反应计算,分析研究青藏铁路沿线冻土区10个冻土场地的地震动加速度时程与加速度反应谱的基本特征及其影响因素,同时,统计研究地温对场地的地震动加速度反应谱的影响。结果表明,青藏铁路沿线多年冻土区土层波速及横波与纵波之波速比值较非冻土区大,地震强度对冻土区场地的地震动加速度幅值具有决定性影响,冻土区典型地震动加速度反应谱的中、短周期成分所占比例较大,冻土场地的地震动加速度反应谱的幅值随地温的降低而普遍减小。
Based on the field geological investigation at permafrost regions,geological description and field test of waves velocities at 14 typical boreholes distributing in permafrost areas along the Qinghai—Tibet Railway,elementary characteristics of wave velocities of soils at the permafrost regions are presented.And then,combining the results of dynamic triaxial test,using three time histories of ground motion acceleration with the exceedance probabilities 62.5%,10.0% and 2.0% in 50 years related to the research area,the characteristics of ground motion are analyzed for the 10 permafrost profiles by an equivalent linearization method to estimate the seismic response of frozen soil ground.Moreover,the influence of earth temperature on seismic acceleration response spectrum for permafrost sites is studied.Consequently,the following conclusions can be drawn.(1)Under the similar conditions,the wave velocities of frozen soils along the Qinghai—Tibet Railway are greater than those of other non-frozen soils areas;and the velocity ratio between the shear wave and compression wave does the same.(2)Earthquake intensity is a critical factor to influence the acceleration amplitude of ground motion at permafrost regions,e.g.with the decrease of earthquake intensity,the acceleration amplitude of the ground motion reduces gradually.(3)The proportion of the moderate and the short periods of seismic acceleration response spectrum in permafrost regions is primary.(4)The amplitude of acceleration response spectrum of ground motion decreases distinctly while earth temperature of frozen soils reduces.The research should contribute to earthquake disaster prevention of engineering structures in permafrost areas on Qinghai—Tibet Plateau.
Based on the field geological investigation at permafrost regions,geological description and field test of waves velocities at 14 typical boreholes distributing in permafrost areas along the Qinghai—Tibet Railway,elementary characteristics of wave velocities of soils at the permafrost regions are presented.And then,combining the results of dynamic triaxial test,using three time histories of ground motion acceleration with the exceedance probabilities 62.5%,10.0% and 2.0% in 50 years related to the research area,the characteristics of ground motion are analyzed for the 10 permafrost profiles by an equivalent linearization method to estimate the seismic response of frozen soil ground.Moreover,the influence of earth temperature on seismic acceleration response spectrum for permafrost sites is studied.Consequently,the following conclusions can be drawn.(1)Under the similar conditions,the wave velocities of frozen soils along the Qinghai—Tibet Railway are greater than those of other non-frozen soils areas;and the velocity ratio between the shear wave and compression wave does the same.(2)Earthquake intensity is a critical factor to influence the acceleration amplitude of ground motion at permafrost regions,e.g.with the decrease of earthquake intensity,the acceleration amplitude of the ground motion reduces gradually.(3)The proportion of the moderate and the short periods of seismic acceleration response spectrum in permafrost regions is primary.(4)The amplitude of acceleration response spectrum of ground motion decreases distinctly while earth temperature of frozen soils reduces.The research should contribute to earthquake disaster prevention of engineering structures in permafrost areas on Qinghai—Tibet Plateau.
引文
[1]周幼吾,郭东信,邱国庆,等.中国冻土[M].北京:科学出版社,2000:1–8.(ZHOU Youwu,GUO Dongxin,QIU Guoqing,et al.Chinese permafrost[M].Beijing:Science Press,2000:1–8.(in Chinese))
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[3]王丽霞,凌贤长,徐学燕,等.多年冻土场地路基地震加速度反应谱特性研究[J].岩石力学与工程学报,2004,23(8):1330–1335.(WANG Lixia,LING Xianchang,XU Xueyan,et al.Study on response spectrum characteristics of earthquake acceleration for roadbed on permafrost site[J].Chinese Journal of Rock Mechanics and Engineering,2004,23(8):1330–1335.(in Chinese))
[4]徐学燕,徐春华,李晓稚.冻土场地地震加速度反应谱研究[J].岩土工程学报,2003,25(6):680–683.(XU Xueyan,XU Chunhua,LI Xiaozhi.Research on earthquake acceleration response spectrum of frozen soil ground[J].Chinese Journal of Geotechnical Engineering,2003,25(6):680–683.(in Chinese))
[5]陆鸣,李小军.青藏铁路四座主要桥梁工程场地地震安全性评价报告[R].哈尔滨:中国地震局工程地震研究中心,2001.(LU Ming,LI Xiaojun.Report of seismic security estimation on engineering site of four bridges in Qinghai—Tibet Railway[R].Harbin:Research Center of Seismic Engineering,China Earthquake Administration,2001.(in Chinese))
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[7]WANG L M,ZHANG D L,WU Z J.The influence of earth temperature on dynamic characteristics of frozen soil and the parameters of ground motion on the sites of permafrost[C]//Proceedings of the16th ICSMGE.Osaka,Japan:[s.n.],2005:2733–2736.
[8]崔托维奇.冻土力学[M].张长庆,朱元林译.北京:科学出版社,1985.(CYTOVICH N A.Mechanics of frozen soil[M].Translated by ZHANG Changqing,ZHU Yuanlin.Beijing:Science Press,1985.(in Chinese))
[9]徐斆祖，王嘉诚，张利新.冻土物理学[M].北京:科学出版社,2001.(XU Xiaozu,WANG Jiacheng,ZHANG Lixin.Physics of frozen soil[M].Beijing:Science Press,2001.(in Chinese))
[10]王昭令.冻土退化与青藏高原冻土环境问题探讨[C]//第5届全国冰川冻土大会论文集.兰州:甘肃文化出版社,1996:11–17.(WANG Zhaoling.An approach on permafrost degradation and environmental problems in the Qinghai—Tibet Plateau[C]//Proceedings of the5th Chinese Conference on Glaciology and Geocryology.Lanzhou:Gansu Culture Press,1996:11–17.(in Chinese))
[11]王国尚,金会军,林清.青藏公路沿线冻土自然环境及工程环境的变化[C]//第5届全国冰川冻土大会论文集.兰州:甘肃文化出版社,1996:43–50.(WANG Guoshang,JIN Huijun,LIN Qing.Changes of natural and engineering environments in permafrost regions along the Qinghai—Tibet Highway[C]//Proceedings of the5th Chinese Conference on Glaciology and Geocryology.Lanzhou:Gansu Culture Press,1996:43–50.(in Chinese))
[12]张鲁新.青藏铁路高原冻土区地温变化规律及其对路基稳定性影响[J].中国铁道科学,2000,21(1):37–47.(ZHANG Luxin.Regularity of ground temperature variation in Qinghai—Tibet Plateau permafrost region and its effect on subgrade stability[J].China Railway Science,2000,21(1):37–47.(in Chinese))
[13]程国栋.用冷却地基的方法修建青藏铁路[J].中国铁道科学,2003,24(3):1–4.(CHENG Guodong.Taking a cooling foundation method to construct Qinghai—Tibet Railway[J].China Railway Science,2003,24(3):1–4.(in Chinese))
[14]王大雁,朱元林,马巍,等.冻土超声波波速与冻土物理力学性质试验研究[J].岩石力学与工程学报,2003,22(11):1837–1840.(WANG Dayan,ZHU Yuanlin,MA Wei,et al.Testing study on relationship between ultrasonic wave velocities and physico-mechanical property of frozen soils[J].Chinese Journal of Rock Mechanics and Engineering,2003,22(11):1837–1840.(in Chinese))
[15]吴志坚,马巍,王兰民,等.地震荷载作用下温度和围压对冻土强度影响的试验研究[J].冰川冻土,2003,25(6):648–652.(WU Zhijian,MA Wei,WANG Lanmin,et al.Laboratory study on the effect of temperature and confining pressure on strength of frozen soil under seismic dynamic loading[J].Journal of Glaciology and Geocryology,2003,25(6):648–652.(in Chinese))
[2]高峰,陈兴冲,严松宏.季节性冻土和多年冻土对场地地震反应的影响[J].岩石力学与工程学报,2006,25(8):1639–1644.(GAO Feng,CHEN Xingchong,YAN Songhong.Influence of permafrost and seasonally frozen soil on seismic responses of sites[J].Chinese Journal of Rock Mechanics and Engineering,2006,25(8):1639–1644.(in Chinese))
[3]王丽霞,凌贤长,徐学燕,等.多年冻土场地路基地震加速度反应谱特性研究[J].岩石力学与工程学报,2004,23(8):1330–1335.(WANG Lixia,LING Xianchang,XU Xueyan,et al.Study on response spectrum characteristics of earthquake acceleration for roadbed on permafrost site[J].Chinese Journal of Rock Mechanics and Engineering,2004,23(8):1330–1335.(in Chinese))
[4]徐学燕,徐春华,李晓稚.冻土场地地震加速度反应谱研究[J].岩土工程学报,2003,25(6):680–683.(XU Xueyan,XU Chunhua,LI Xiaozhi.Research on earthquake acceleration response spectrum of frozen soil ground[J].Chinese Journal of Geotechnical Engineering,2003,25(6):680–683.(in Chinese))
[5]陆鸣,李小军.青藏铁路四座主要桥梁工程场地地震安全性评价报告[R].哈尔滨:中国地震局工程地震研究中心,2001.(LU Ming,LI Xiaojun.Report of seismic security estimation on engineering site of four bridges in Qinghai—Tibet Railway[R].Harbin:Research Center of Seismic Engineering,China Earthquake Administration,2001.(in Chinese))
[6]廖振鹏,李小军.地表土层地震反应的等效线性化解法[C]//地震小区划——理论与实践.北京:地震出版社,1989:141–153.(LIAO Zhenpeng,LI Xiaojun.An equivalent linearization method to estimate seismic response of soils at ground surface[C]//Seismic Micro-zoning—Theory and Practice.Beijing:Earthquake Press,1989:141–153.(in Chinese))
[7]WANG L M,ZHANG D L,WU Z J.The influence of earth temperature on dynamic characteristics of frozen soil and the parameters of ground motion on the sites of permafrost[C]//Proceedings of the16th ICSMGE.Osaka,Japan:[s.n.],2005:2733–2736.
[8]崔托维奇.冻土力学[M].张长庆,朱元林译.北京:科学出版社,1985.(CYTOVICH N A.Mechanics of frozen soil[M].Translated by ZHANG Changqing,ZHU Yuanlin.Beijing:Science Press,1985.(in Chinese))
[9]徐斆祖，王嘉诚，张利新.冻土物理学[M].北京:科学出版社,2001.(XU Xiaozu,WANG Jiacheng,ZHANG Lixin.Physics of frozen soil[M].Beijing:Science Press,2001.(in Chinese))
[10]王昭令.冻土退化与青藏高原冻土环境问题探讨[C]//第5届全国冰川冻土大会论文集.兰州:甘肃文化出版社,1996:11–17.(WANG Zhaoling.An approach on permafrost degradation and environmental problems in the Qinghai—Tibet Plateau[C]//Proceedings of the5th Chinese Conference on Glaciology and Geocryology.Lanzhou:Gansu Culture Press,1996:11–17.(in Chinese))
[11]王国尚,金会军,林清.青藏公路沿线冻土自然环境及工程环境的变化[C]//第5届全国冰川冻土大会论文集.兰州:甘肃文化出版社,1996:43–50.(WANG Guoshang,JIN Huijun,LIN Qing.Changes of natural and engineering environments in permafrost regions along the Qinghai—Tibet Highway[C]//Proceedings of the5th Chinese Conference on Glaciology and Geocryology.Lanzhou:Gansu Culture Press,1996:43–50.(in Chinese))
[12]张鲁新.青藏铁路高原冻土区地温变化规律及其对路基稳定性影响[J].中国铁道科学,2000,21(1):37–47.(ZHANG Luxin.Regularity of ground temperature variation in Qinghai—Tibet Plateau permafrost region and its effect on subgrade stability[J].China Railway Science,2000,21(1):37–47.(in Chinese))
[13]程国栋.用冷却地基的方法修建青藏铁路[J].中国铁道科学,2003,24(3):1–4.(CHENG Guodong.Taking a cooling foundation method to construct Qinghai—Tibet Railway[J].China Railway Science,2003,24(3):1–4.(in Chinese))
[14]王大雁,朱元林,马巍,等.冻土超声波波速与冻土物理力学性质试验研究[J].岩石力学与工程学报,2003,22(11):1837–1840.(WANG Dayan,ZHU Yuanlin,MA Wei,et al.Testing study on relationship between ultrasonic wave velocities and physico-mechanical property of frozen soils[J].Chinese Journal of Rock Mechanics and Engineering,2003,22(11):1837–1840.(in Chinese))
[15]吴志坚,马巍,王兰民,等.地震荷载作用下温度和围压对冻土强度影响的试验研究[J].冰川冻土,2003,25(6):648–652.(WU Zhijian,MA Wei,WANG Lanmin,et al.Laboratory study on the effect of temperature and confining pressure on strength of frozen soil under seismic dynamic loading[J].Journal of Glaciology and Geocryology,2003,25(6):648–652.(in Chinese))
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