混凝土坝坝体配筋抗震措施研究
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摘要
已有研究表明,对混凝土坝抗震采用线弹性分析得到的最大拉应力远大于混凝土的抗拉强度,在强震作用下,坝体将不可避免地产生开裂。本文以拉压应力损伤因子为内变量,采用混凝土塑性损伤模型,分析了坝体在地震荷载作用下的刚度退化以及在多维应力状态下拉应力引起的损伤破坏。在抗震措施方面,文中研究了塑性损伤模型的配筋模拟,并针对印度Koyna坝的震害情况,根据配筋前的塑性损伤分析,设置了两种不同的配筋方案,据此进行了塑性损伤动力分析,给出了配筋前后坝体的拉应力损伤因子分布及坝顶动位移响应。通过计算比较了配筋前后坝体的拉应力损伤因子分布范围及坝顶动位移响应,结果说明,配筋抗震措施能够明显地减小坝体损伤区的范围,显著限制坝体损伤区的扩展与贯穿,有效地改善了坝体的抗震性能。
The known studies indicate that peak tensile stress occurred at the upper portion of concrete gravity dam is much higher than the dynamic tensile strength of concrete during strong earthquake which resulted in the inevitably happening of cracking.In this paper,the stiffness degradation and damage failure in concrete dams subjected to strong ground motion are simulated by plastic-damage model based on damage index variable.A seismic resistance measure by adding reinforcement in monolith to strengthen the dam is suggested,and its effectiveness is verified by numerical modeling of the Koyna Dam,India.Two alternatives of reinforcement are to be considered.The comparison of calculation results shows that this measure can effectively reduce the damage zone and significantly control the extension of damage zone.
The known studies indicate that peak tensile stress occurred at the upper portion of concrete gravity dam is much higher than the dynamic tensile strength of concrete during strong earthquake which resulted in the inevitably happening of cracking.In this paper,the stiffness degradation and damage failure in concrete dams subjected to strong ground motion are simulated by plastic-damage model based on damage index variable.A seismic resistance measure by adding reinforcement in monolith to strengthen the dam is suggested,and its effectiveness is verified by numerical modeling of the Koyna Dam,India.Two alternatives of reinforcement are to be considered.The comparison of calculation results shows that this measure can effectively reduce the damage zone and significantly control the extension of damage zone.
引文
[1]Koyna Earthquake of December 1967[M].Report of the UNESCO Committee of Experts,New Delhi,1968.
[2]陈厚群.大坝抗震[A].中国大坝50年[C].北京:中国水利水电出版社,2000.675-733.
[3]李瓒,陈兴华,郑建波,王光纶.混凝土拱坝设计[M].北京:中国电力出版社,2000.
[4]Hinks J L,Gosschalk E M.Dam and earthquake[J].Dam Engineering,1993,4(1):9-24.
[5]Zhang Chuhan,Xu Yanjie,Wang Guanglun,et al.Nonlinear seismic response of arch dams with contraction joint openingand joint reinforcements[J].Earthquake Engineering and Structural Dynamics,2000,29(10):1547-1566.
[6]Zhang Chu-han,et al.Numerical Model of Concrete Dam-Foundation-Reservior systems[M].Beijing:Tsinghua UniversityPress,2001.
[7]郭永刚,涂劲,陈厚群.高拱坝伸缩横缝间布设阻尼器对坝体地震反应影响的研究[J].世界地震工程,2003,19(3):44-49.
[8]郭永刚,涂劲,陈厚群.抗震钢筋对高拱坝抗震性能的影响[J].水利学报,2004,35(3):1-6.
[9]Mohamed L A,Victor E S.A fracture mechanics based seismic analysis of concrete gravity dams using discrete cracks[J].Engineering Fracture Mechanics,1990,35(1):587-598.
[10]Pekau O A,Zhang Chuhan,Feng Lingmin.Seismic fracture analysis of concrete gravity dams[J].Earthquake Engineeringand Structural Dynamics,1991,20(4):335-354.
[11]El-Aidi B,Hall JF.Nonlinear earthquake response of concrete gravity dams[J].PartⅠ:Modeling,EarthquakeEngineering and Structural Dynamics,1989,18(6):837-851.
[12]Bhattacharjee S S,Leger P.Seismic cracking and energy dissipation in concrete gravity dams[J].Earthquake Engineeringand Structural Dynamics,1993,22(11):991-1007.
[13]Ghrib Faouzi,Tinwai Ren.éAn application of damage mechanics for seismic analysis of concrete gravity dams[J].Earthquake Engineering and Structural Dynamics,1995,24(2):157-173.
[14]Wang Guanglun,Pekau O A,Zhang Chuhan,Wang Shaomin.Seismic fracture analysis of concrete gravity dams based onnonlinear fracture mechanics[J].Engineering Fracture Mechanics,2000,65(1):67-87.
[15]邱战洪,张我华,任廷鸿.地震荷载作用下大坝系统的非线性动力损伤分析[J].水利学报,2005,36(5):629-636.
[16]Yusurf Calayir,Muhammet Kratan.A continuum damage concrete model for earthquake analysis of concrete gravity dam—reservoir systems[J].Soil Dynamic and Earthquake Engineering,2005,25(11):857-869.
[17]Lee J,Fenves G L.Plastic-damage model for cyclic loading of concrete structures[J].Journal of Engineering Mechanics,ASCE 1998,124(8):892-900.
[18]Lee J,Fenves G L.A Plastic-damage concrete model for earthquake analysis of dams[J].Earthquake Engineering andStructural Dynamics,1998,27(9):937-956.
[19]Maekawa K,Pimanmas A,Okamura H.Nonlinear Mechanics of Reinforced Concrete[M].Spon Press,11 New FetterLane,London EC4P 4EE,2003.
[20]Xuehui An,Maekawa K,Okamura H.Numerical simulation of size effect in shear strength of RC beams[J].ConcreteLibrary of JSCE,1998,31:323-346.
[2]陈厚群.大坝抗震[A].中国大坝50年[C].北京:中国水利水电出版社,2000.675-733.
[3]李瓒,陈兴华,郑建波,王光纶.混凝土拱坝设计[M].北京:中国电力出版社,2000.
[4]Hinks J L,Gosschalk E M.Dam and earthquake[J].Dam Engineering,1993,4(1):9-24.
[5]Zhang Chuhan,Xu Yanjie,Wang Guanglun,et al.Nonlinear seismic response of arch dams with contraction joint openingand joint reinforcements[J].Earthquake Engineering and Structural Dynamics,2000,29(10):1547-1566.
[6]Zhang Chu-han,et al.Numerical Model of Concrete Dam-Foundation-Reservior systems[M].Beijing:Tsinghua UniversityPress,2001.
[7]郭永刚,涂劲,陈厚群.高拱坝伸缩横缝间布设阻尼器对坝体地震反应影响的研究[J].世界地震工程,2003,19(3):44-49.
[8]郭永刚,涂劲,陈厚群.抗震钢筋对高拱坝抗震性能的影响[J].水利学报,2004,35(3):1-6.
[9]Mohamed L A,Victor E S.A fracture mechanics based seismic analysis of concrete gravity dams using discrete cracks[J].Engineering Fracture Mechanics,1990,35(1):587-598.
[10]Pekau O A,Zhang Chuhan,Feng Lingmin.Seismic fracture analysis of concrete gravity dams[J].Earthquake Engineeringand Structural Dynamics,1991,20(4):335-354.
[11]El-Aidi B,Hall JF.Nonlinear earthquake response of concrete gravity dams[J].PartⅠ:Modeling,EarthquakeEngineering and Structural Dynamics,1989,18(6):837-851.
[12]Bhattacharjee S S,Leger P.Seismic cracking and energy dissipation in concrete gravity dams[J].Earthquake Engineeringand Structural Dynamics,1993,22(11):991-1007.
[13]Ghrib Faouzi,Tinwai Ren.éAn application of damage mechanics for seismic analysis of concrete gravity dams[J].Earthquake Engineering and Structural Dynamics,1995,24(2):157-173.
[14]Wang Guanglun,Pekau O A,Zhang Chuhan,Wang Shaomin.Seismic fracture analysis of concrete gravity dams based onnonlinear fracture mechanics[J].Engineering Fracture Mechanics,2000,65(1):67-87.
[15]邱战洪,张我华,任廷鸿.地震荷载作用下大坝系统的非线性动力损伤分析[J].水利学报,2005,36(5):629-636.
[16]Yusurf Calayir,Muhammet Kratan.A continuum damage concrete model for earthquake analysis of concrete gravity dam—reservoir systems[J].Soil Dynamic and Earthquake Engineering,2005,25(11):857-869.
[17]Lee J,Fenves G L.Plastic-damage model for cyclic loading of concrete structures[J].Journal of Engineering Mechanics,ASCE 1998,124(8):892-900.
[18]Lee J,Fenves G L.A Plastic-damage concrete model for earthquake analysis of dams[J].Earthquake Engineering andStructural Dynamics,1998,27(9):937-956.
[19]Maekawa K,Pimanmas A,Okamura H.Nonlinear Mechanics of Reinforced Concrete[M].Spon Press,11 New FetterLane,London EC4P 4EE,2003.
[20]Xuehui An,Maekawa K,Okamura H.Numerical simulation of size effect in shear strength of RC beams[J].ConcreteLibrary of JSCE,1998,31:323-346.
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