青藏高原北部移动冰丘破坏桥墩的数值模拟
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摘要
青藏高原北部常年冻土区断裂破碎带发育的移动冰丘对桥梁、涵洞、输油管道等工程设施具有不同形式的破坏作用。考虑移动冰丘与工程设施的相互作用,根据野外观测和实验资料设计模型,应用三维有限元数值模拟方法,计算移动冰丘冻胀产生的位移场、应力场和桥墩弯曲应力,分析桥墩破裂机理。结果表明,移动冰丘能够产生11~-21MPa的轴向应力和15~-31 MPa的主应力,在桥墩周围形成不同规模的应力集中区,导致桥墩发生显著偏移。桥墩的偏移和弯曲能够在桥墩内部产生高达61.9~64.6 MPa的张应力和-45.0~-49.0 MPa的压应力,超过桥墩的强度极限。在粗细桥墩连接部位,外侧形成张应力集中区,最大张应力达26~30 MPa;内侧形成压应力集中区,最大压应力达-25~-28.8 MPa。粗细桥墩连接部位外侧的张应力超过了钢筋混凝土的抗张强度,产生与野外观测资料基本吻合的桥墩破裂和结构破坏。移动冰丘导致桥墩变形破坏的三维有限元数值模拟能够为常年冻土区桥梁工程设计和地质灾害防治提供力学参数和科学依据。
Migrating pingos formed along fault zone in permafrost north Tibetan Plateau,destructing bridge,culvert and oil pipeline.Here displacement and stress fields caused by migrating pingos and stresses of bended bridge pier were calculated by three dimensional finite element modeling based on field observation and laboratory tests,and breaking mechanism of bridge pier was analyzed after the numerical modeling.It is proved that expansion of migrating pingo can produce axis stress of 11 to-21 MPa,formed concentration of stresses and caused evident displacement and deviation of bridge pier.The bending and deviation further result in extensional stress of 61.9 to 64.6 MPa and compressional stress of-45.0 to-49.0 MPa within the bridge pier,exceeding strength limit of the bridge pier.And stress concentration forms in size change area of upper bridge pier with maximum extensional stress of 26 to 30 MPa and maximum compressional stress of-25 to-28.8 MPa.The maximum extensional stress concentrated in size change area also exceeds strength limit of the bridge pier,formed shear-extensional fractures of the Chumaerhe Bridge.Three dimensional numerical modeling on migrating pingo destructing bridge pier can provide important factors for designing bridge and protecting geological hazard in permafrost.
Migrating pingos formed along fault zone in permafrost north Tibetan Plateau,destructing bridge,culvert and oil pipeline.Here displacement and stress fields caused by migrating pingos and stresses of bended bridge pier were calculated by three dimensional finite element modeling based on field observation and laboratory tests,and breaking mechanism of bridge pier was analyzed after the numerical modeling.It is proved that expansion of migrating pingo can produce axis stress of 11 to-21 MPa,formed concentration of stresses and caused evident displacement and deviation of bridge pier.The bending and deviation further result in extensional stress of 61.9 to 64.6 MPa and compressional stress of-45.0 to-49.0 MPa within the bridge pier,exceeding strength limit of the bridge pier.And stress concentration forms in size change area of upper bridge pier with maximum extensional stress of 26 to 30 MPa and maximum compressional stress of-25 to-28.8 MPa.The maximum extensional stress concentrated in size change area also exceeds strength limit of the bridge pier,formed shear-extensional fractures of the Chumaerhe Bridge.Three dimensional numerical modeling on migrating pingo destructing bridge pier can provide important factors for designing bridge and protecting geological hazard in permafrost.
引文
[1]W u Zhenhan,Barosh P J,Hu Daogong,et al.M igrating p ingosin the permafrost region of the Tibetan P lateau,Ch ina and theirhazard along the Golmud-Lhasa railway[J].Engineering Geolo-gy,2005,79:267-287.
[2]胡海涛,任国林,孙存煜.青南—藏北高原多年冻土区近代冻融物理地质现象的类型及其特征[M]//地质矿产部青藏高原地质文集编委会.青藏高原地质文集(5).北京:地质出版社,1982:101-112.
[3]王邵令.青藏高原清水河两岸的冻胀丘[J].冰川冻土,1981,3(3):58-62.
[4]吴珍汉,叶培盛,吴中海,等.青藏铁路沿线活动断裂的灾害效应[J].现代地质,2003,17(1):1-7.
[5]吴珍汉,吴中海,张永双,等.青海西南部乌丽活动断裂系的地质特征及灾害效应[J].地质通报,2003,22(6):437-444.
[6]Wu Zhenhan,Barosh P J,Hu Daogong,et al.Hazards posed by activemajor faults along the Golmud-Lhasa railway route,Tibetan Plateau,China[J].Engineering Geology,2004,74(3-4):163-182.
[7]吴珍汉,吴中海,胡道功,等.青藏铁路沿线活动断裂与地质灾害图集[M].北京:地震出版社,2005.
[8]刘永智,吴青柏,张建民,等.高原多年冻土地区公路路基温度场现场实验研究[J].公路,2000,8(2):5-8.
[9]吴青柏,李新,李文君.青藏公路沿线冻土区域分布计算机模拟与制图[J].冰川冻土,2000,22(4):323-326.
[10]曹东伟,胡长顺.多年冻土区路基融沉变形的附加应力分析[J].重庆交通学院学报,2001,20(3):57-61.
[11]喻文兵,朱源林,张建明,等.用钻孔旁压试验原位测试冻土力学性质的探讨[J].冰川冻土,2000,22(4):366-371.
[12]鲁国威,徐祖,童长江,等.冻土工程地质勘察规范———中华人民共和国国家标准GB50324-2001[M].北京:中国计划出版社,2001:75-77.
[13]王正中,沙际德,蒋允静,等.正交各向异性冻土与建筑物相互作用的非线性有限元分析[J].土木工程学报,1999,32(3):55-60.
[14]王正中,张长庆,沙际德.冻土和扩大台基相互作用的有限元分析[J].西北农业大学学报,1998,26(5):9-14.
[15]华东水利学院.弹性力学有限元法[M].北京:水利电力出版社,1974.
[16]丁靖康,赫贵生.年平均气温临界值———设计青藏高原多年冻土路堤临界高度的一个重要因素[J].冰川冻土,2000,22(4):333-339.
[17]沙际德,张长庆,王正中.粉土自由冻胀参数的实验研究[M]//中国科学院兰州冰川冻土研究所.第五届全国冻土学术会议论文集.北京:科学出版社,1996:1201-1207.
[18]张长庆,于志秋.正交各向异性冻土的力学参数实验[J].冰川与冻土,1996,18(增刊):40-46.
[19]廖椿庭,吴满路,张春山,等.青藏高原昆仑山和羊八井现今地应力测量及其工程意义[J].地球学报,2002,23(4):353-358.
[20]Liao Chunting,Zhang Chunshan,Wu Manlu,et al.Stress changenear the Kunlun fault before and after theMs 8.1 Kunlun earthquake[J].Geophysical Research Letters,2003,30(20):31-34.
[21]尉希成.支挡结构设计手册[M].北京:中国建筑工业出版社,1995.
[2]胡海涛,任国林,孙存煜.青南—藏北高原多年冻土区近代冻融物理地质现象的类型及其特征[M]//地质矿产部青藏高原地质文集编委会.青藏高原地质文集(5).北京:地质出版社,1982:101-112.
[3]王邵令.青藏高原清水河两岸的冻胀丘[J].冰川冻土,1981,3(3):58-62.
[4]吴珍汉,叶培盛,吴中海,等.青藏铁路沿线活动断裂的灾害效应[J].现代地质,2003,17(1):1-7.
[5]吴珍汉,吴中海,张永双,等.青海西南部乌丽活动断裂系的地质特征及灾害效应[J].地质通报,2003,22(6):437-444.
[6]Wu Zhenhan,Barosh P J,Hu Daogong,et al.Hazards posed by activemajor faults along the Golmud-Lhasa railway route,Tibetan Plateau,China[J].Engineering Geology,2004,74(3-4):163-182.
[7]吴珍汉,吴中海,胡道功,等.青藏铁路沿线活动断裂与地质灾害图集[M].北京:地震出版社,2005.
[8]刘永智,吴青柏,张建民,等.高原多年冻土地区公路路基温度场现场实验研究[J].公路,2000,8(2):5-8.
[9]吴青柏,李新,李文君.青藏公路沿线冻土区域分布计算机模拟与制图[J].冰川冻土,2000,22(4):323-326.
[10]曹东伟,胡长顺.多年冻土区路基融沉变形的附加应力分析[J].重庆交通学院学报,2001,20(3):57-61.
[11]喻文兵,朱源林,张建明,等.用钻孔旁压试验原位测试冻土力学性质的探讨[J].冰川冻土,2000,22(4):366-371.
[12]鲁国威,徐祖,童长江,等.冻土工程地质勘察规范———中华人民共和国国家标准GB50324-2001[M].北京:中国计划出版社,2001:75-77.
[13]王正中,沙际德,蒋允静,等.正交各向异性冻土与建筑物相互作用的非线性有限元分析[J].土木工程学报,1999,32(3):55-60.
[14]王正中,张长庆,沙际德.冻土和扩大台基相互作用的有限元分析[J].西北农业大学学报,1998,26(5):9-14.
[15]华东水利学院.弹性力学有限元法[M].北京:水利电力出版社,1974.
[16]丁靖康,赫贵生.年平均气温临界值———设计青藏高原多年冻土路堤临界高度的一个重要因素[J].冰川冻土,2000,22(4):333-339.
[17]沙际德,张长庆,王正中.粉土自由冻胀参数的实验研究[M]//中国科学院兰州冰川冻土研究所.第五届全国冻土学术会议论文集.北京:科学出版社,1996:1201-1207.
[18]张长庆,于志秋.正交各向异性冻土的力学参数实验[J].冰川与冻土,1996,18(增刊):40-46.
[19]廖椿庭,吴满路,张春山,等.青藏高原昆仑山和羊八井现今地应力测量及其工程意义[J].地球学报,2002,23(4):353-358.
[20]Liao Chunting,Zhang Chunshan,Wu Manlu,et al.Stress changenear the Kunlun fault before and after theMs 8.1 Kunlun earthquake[J].Geophysical Research Letters,2003,30(20):31-34.
[21]尉希成.支挡结构设计手册[M].北京:中国建筑工业出版社,1995.
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