强地震作用下高拱坝的破坏分析
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摘要
结合混凝土静动态试验,根据连续损伤力学中能量等效原理和有效应力概念,建立了能反映混凝土动态情况下多轴弹塑性损伤破坏模型,该模型考虑了多轴损伤变量和应变率的影响。采用本文模型对强地震作用下(峰值地震加速度为0.557 5g)大岗山拱坝动力响应进行了数值模拟,获得地震全过程拱坝拉损伤、压损伤、总体损伤模式和应变率响应。分析表明,大坝破损的主要原因是由于混凝土的拉伸作用,所得到的大坝破坏模式和模型试验结果一致;大坝不同部位有着明显不同的率响应,其将很大程度上影响坝体混凝土的动态性能。借助损伤力学理论评价了大坝强震后的安全性,结果显示大坝在经历强震作用后总体损伤不大,但坝体存在抗震薄弱部位,设计和施工中应注意采取措施处理。
Based on the theory of energy equivalent and the concept of effective stress in damage mechanics the rate-dependent elastoplastic damage-failure model with multiaxial effect taken into account is proposed.The validity of the model is verified by the numerical simulation of a concrete stub which is experimentally studied by Tikhomirov and Stein in 2001.On this basis,the model is applied to numerical simulation of high arch dam subjected to designed strong earthquake,with maximum acceleration 0.5575gm /s-2,by using the FEM method.Not only the tensile and compressive damage but also the global damage pattern and strain rate response in the whole process of earthquake are obtained.It is found that the tensile damage is the primary cause of dam failure.The strain rate response which significantly affects the dynamic characteristics of concrete varies in different zone of the dam.The global damage situation indicates that the dam has sufficient safety in resisting the designed strong earthquake.The failure procedure of the simulation result is in good agreement with that of model test.
Based on the theory of energy equivalent and the concept of effective stress in damage mechanics the rate-dependent elastoplastic damage-failure model with multiaxial effect taken into account is proposed.The validity of the model is verified by the numerical simulation of a concrete stub which is experimentally studied by Tikhomirov and Stein in 2001.On this basis,the model is applied to numerical simulation of high arch dam subjected to designed strong earthquake,with maximum acceleration 0.5575gm /s-2,by using the FEM method.Not only the tensile and compressive damage but also the global damage pattern and strain rate response in the whole process of earthquake are obtained.It is found that the tensile damage is the primary cause of dam failure.The strain rate response which significantly affects the dynamic characteristics of concrete varies in different zone of the dam.The global damage situation indicates that the dam has sufficient safety in resisting the designed strong earthquake.The failure procedure of the simulation result is in good agreement with that of model test.
引文
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[8]潘坚文,王进廷,张楚汉.超强震作用下拱坝的损伤开裂分析[J].水利学报,2007,38(2):143-149.
[9]钟红,林皋,李建波,等.高拱坝地震损伤破坏的数值模拟[J].水利学报,2008,39(7):845-553.
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[12]彼莱奇科.连续体和结构的非线性有限元[M].廖荣锦,默然,庄茁,译.北京:清华大学出版社,2002:239-255.
[13]Tikhomirov D,Stein E.Finite element computations of anisotropic continuum damage in reinforced concrete[J].Computers and Structures,2001,79:2246-2260.
[14]范书立,陈健云,王建涌,等.高拱坝振动台地震破坏试验研究及数值仿真[J].岩石力学与工程学报,2009,28(3):467-474.
[2]Faria R,Oliver J,Cervera M.Modeling material failure in concrete structures under cyclic actions[J].Journal ofStructural Engineering,2004,130(12):1997-2005.
[3]Valliappan S,Yazdchi M,Khalili N.Seismic analysis of arch dams-a continuum damage mechanics approach[J].International Journal of Numerical Methods in Engineering,1999,45:1695-1724.
[4]Zhou W,Zhao J,Liu Y,et al.Simulation of localization failure with strain-gradient-enhanced damagemechanics[J].International Journal of Numerical Analysis for Methods in Geomechanics,2002,26:793-813.
[5]陈健云,林皋,胡志强.考虑混凝土应变率变化的高拱坝非线性动力响应研究[J].计算力学学报,2004,21(1):45-49.
[6]李静,陈健云,白卫峰.基于应变率相关的非线性损伤模型在高拱坝横缝开度分析中的应用[J].水利学报,2005,36(7):870-875.
[7]杜荣强,林皋.混凝土弹塑性多轴损伤模型及其应用[J].大连理工大学学报,2007,47(4):567-572.
[8]潘坚文,王进廷,张楚汉.超强震作用下拱坝的损伤开裂分析[J].水利学报,2007,38(2):143-149.
[9]钟红,林皋,李建波,等.高拱坝地震损伤破坏的数值模拟[J].水利学报,2008,39(7):845-553.
[10]CEB.Concrete structures under impact and impulsive loading[R].Synthesis Report,Bulletin d’Information No.187.Lausanne:Comite’Euro-International du Be′ton,1988.
[11]Park H,Kim J.Plasticity model using multiple failure criteria for concrete in compression[J].InternationalJournal of Solids and Structures,2005,42:2303-2322.
[12]彼莱奇科.连续体和结构的非线性有限元[M].廖荣锦,默然,庄茁,译.北京:清华大学出版社,2002:239-255.
[13]Tikhomirov D,Stein E.Finite element computations of anisotropic continuum damage in reinforced concrete[J].Computers and Structures,2001,79:2246-2260.
[14]范书立,陈健云,王建涌,等.高拱坝振动台地震破坏试验研究及数值仿真[J].岩石力学与工程学报,2009,28(3):467-474.
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