塔城心墙堆石坝地震反应分析
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摘要
塔城砾石土心墙堆石坝最大坝高315m,地震动作用下,坝身特别是坝体上部容易出现严重裂缝或者坝坡失稳等问题。为了考察高土石坝经历高震级地震时的抗震性能,坝体及覆盖层材料采用Hardin非线性动力模型,在三维非线性静力分析基础上,用时程法对大坝进行地震动力分析,以揭示在Taft三向地震波的作用过程中坝体中加速度、动位移、动应力的分布及其地震永久变形和液化情况。坝体非线性仿真结果表明,在设防烈度地震作用下,在坝体最大断面上,坝顶动力放大系数为2.5左右,1/2坝高小范围内有拉应力出现,坝体沉陷及向下游水平位移较大,坝踵坝趾局部有一定的液化可能。
It is likely to emerge serious problems in the Tacheng Core-wall Rock-fill Dam, whose maximum height is up to 315 m, such as cracks, especially generating at the top of it, and instability of dam slope, when subjected to earthquake. The material of dam body and covering layers were simulated by the Hardin nonlinear dynamic constitutive model. On the basis of nonlinear static analysis, the time-history analysis was carried out to explore the earthquake-resistant characteristics of the high dam. The distribution of acceleration, dynamic displacement and stress in the dam, permanent displacement, and liquefaction were studied in detail. The results obtained from the three-dimensional nonlinear FEM indicate that the dynamical magnification factor is about 2.5, a tensile stress zone occurs in the region of one half of the dam, dam body evidenttly settles and larger displacement toward downstream also appears, and soil may be liquefied at the foot of the dam partially.
It is likely to emerge serious problems in the Tacheng Core-wall Rock-fill Dam, whose maximum height is up to 315 m, such as cracks, especially generating at the top of it, and instability of dam slope, when subjected to earthquake. The material of dam body and covering layers were simulated by the Hardin nonlinear dynamic constitutive model. On the basis of nonlinear static analysis, the time-history analysis was carried out to explore the earthquake-resistant characteristics of the high dam. The distribution of acceleration, dynamic displacement and stress in the dam, permanent displacement, and liquefaction were studied in detail. The results obtained from the three-dimensional nonlinear FEM indicate that the dynamical magnification factor is about 2.5, a tensile stress zone occurs in the region of one half of the dam, dam body evidenttly settles and larger displacement toward downstream also appears, and soil may be liquefied at the foot of the dam partially.
引文
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[2]SERFF N.Earthquake induced deformation of earth dams[R].Berkeley:Earthquake Engineering Research Cen-ter,Univ.of California,1976.
[3]倪汉根,金崇磐.大坝抗震特性与抗震计算[M].大连:大连理工出版社,1994.(NI Han-en,JIN Chong-pan.The Aseismatic Character and Numeration of Dam[M].Dalian:Dalian University of Technology Press,1994.(in Chinese))
[4]顾淦臣.土石坝地震工程[M].南京:河海大学出版社,1989.(GU Gan-cheng.Earthquake Engineering of Earth and Rockfill Dam[M].Nanjing:Hehai University Press,1989.(in Chinese))
[5]陈慧远.土石坝有限元分析[M].南京:河海大学出版社,1987.(CHEN Hui-yuan.Finite Element Analysis on Earth and Rockfill Dam[M].Nanjing:Hehai University Press,1987.(in Chinese))
[6]沈慧,迟世春,贾宇峰,等.覆盖层地基上250m级土石坝抗震分析[J].河海大学学报(自然科学版),2007,35(3):271-275.(SHEN Hui,CHI Shi-chun,JIAYu-fang,et al.Seismic response analysis of250m high earth-rock dam on overburden foundation[J].Journal of Hehai University(Natural Sciences),2007,35(3):271-275.(in Chinese))
[7]费康,朱凯,刘汉龙,等.深厚覆盖层上高土石坝抗震稳定性的三维分析[J].扬州大学学报(自然科学版),2008,11(1):74-78.(FEI Kang,ZHU Kai,JIU Han-long,et al.Three dimensional analysis of the aseis-matic stability of high earth-rockfill dam on deep overbur-den[J].Journal of Yangzhou University(Natural Sci-ence Edition),2008,11(1):74-78.(in Chinese))
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