白鹤滩拱坝底孔应力分析及配筋设计研究
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摘要
高拱坝孔口周围应力分布复杂,需适当配筋改善孔口结构的受力状态,保证拱坝的安全运行。以白鹤滩拱坝3~#底孔为例,首先对施工期工况下孔口结构进行三维有限元计算,分析孔口周围的应力分布规律和产生机理,然后依据应力图形法对孔口进行配筋设计,最后采用钢筋混凝土有限元法对完成配筋的孔口进行非线性分析。结果表明:在坝体自重的作用下,混凝土泊松比效应是引起孔口顶、底板出现顺河向拉应力的主要原因;钢筋整体应力不高,配筋设计方案有较大的安全裕度,应力图形法偏于保守。但出于安全考虑,仍应采用应力图形法进行配筋设计。
The stress distribution around the orifice of high arch dam is complex,while proper reinforcements is necessary to improve the stress state of the orifice structure and ensure safe operation of arch dam. Taking the No. 3 bottom orifice of the Baihetan Arch Dam as an example,a 3-D finite element calculation was firstly made on the orifice structure under construction condition for analyzing the the stress distribution and mechanism around the orifice. Then the stress graph method was used to obtain a reinforcement design of the orifice. Finally,the non-linear calculation of reinforced concrete was carried out for the orifice with reinforcement. The results showed that the Poisson’s ratio effect of concrete was the main cause of the tensile stress along the river at the top and bottom of the orifice under the action of gravity of dam body. The overall stress of the reinforcement was not high,and the reinforcement design scheme had a great safety margin,which means the stress graph method is conservative. However,the stress graph method should still be adopted for the reinforcement design in terms of safety.
The stress distribution around the orifice of high arch dam is complex,while proper reinforcements is necessary to improve the stress state of the orifice structure and ensure safe operation of arch dam. Taking the No. 3 bottom orifice of the Baihetan Arch Dam as an example,a 3-D finite element calculation was firstly made on the orifice structure under construction condition for analyzing the the stress distribution and mechanism around the orifice. Then the stress graph method was used to obtain a reinforcement design of the orifice. Finally,the non-linear calculation of reinforced concrete was carried out for the orifice with reinforcement. The results showed that the Poisson’s ratio effect of concrete was the main cause of the tensile stress along the river at the top and bottom of the orifice under the action of gravity of dam body. The overall stress of the reinforcement was not high,and the reinforcement design scheme had a great safety margin,which means the stress graph method is conservative. However,the stress graph method should still be adopted for the reinforcement design in terms of safety.
引文
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[3]张建海,何江达.坝身孔口群应力分析的子结构单元法[J].水电站设计,1999,15(2):26-32.
[4]谭林,郭原.开孔有限平板应力集中问题的有限元分析[J].重庆理工大学学报,2015,29(7):35-39.
[5]郭晓晶,徐谨谨.子模型法在拱坝泄水底孔应力分析中的应用[J].水利与建筑工程学报,2014,12(1):205-208+212.
[6]李守义,杨胜,高菊梅.拱坝泄水孔应力影响因素分析[J].应用基础与工程科学学报,2010,18(1):20-27.
[7]韩玉莲,赵继勋,高阳,等.基于有限元单元法的混凝土结构配筋方法研究[J].水科学与工程技术,2011(4):87-89.
[8]李鹏冲.万家口子拱坝冲沙中孔配筋设计[J].红水河,2016,35(5):30-33.
[9]殷鸣,李同春,赵兰浩,等.基于单弹簧联结单元法的白鹤滩拱坝孔口配筋非线性有限元分析[J].水利水电技术,2017,48(1):52-58.
[10]赵兰浩,张梦迪,张云峰.表孔闸墩颈部钢筋混凝土非线性有限元分析[J].水电能源科学,2018,36(1):120-123+115.
[11]李同春,李淼,温召旺,等.局部非协调网格在高拱坝应力分析中的应用[J].河海大学学报(自然科学版),2003,31(1):42-45.
[12]侯化强,王连国,陆银龙,等.矩形巷道围岩应力分布及其破坏机理研究[J].地下空间与工程学报,2011,7(S2):1625-1629.
[13]朱峰林,李同春.地震作用下某混凝土拱坝表孔孔口配筋设计[J].水电能源科学,2016,34(6):75-79.
[14]韦未,李同春,姚纬明.建立在应变空间上的混凝土四参数破坏准则[J].水利水电科技进展,2004,24(5):27-29+68.
[15]韦未,李同春.基于四参数等效应变的各向同性损伤模型[J].河海大学学报(自然科学版),2004,32(4):425-429.
[16]颜天佑,李同春,赵兰浩.单弹簧联结单元法的改进算法[J].三峡大学学报(自然科学版),2011,33(6):23-26+32.
[17]ZHAO Lanhao,ZHANG Wei,BAI Xin,et al.Single spring joint element based on the mixed coordinate system[J].Mathematical Problems in Engineering,2015(18):1-16.