毕业设计--土木工程 02 - 图文(2)

学生姓名 王松 学号 20050068 班级 土0501-2 专业 土木工程 双壁钢围堰的截面形式已不仅仅局限于圆形，像武汉军山长江大桥已使用异型双壁钢围堰和矩形双壁钢围堰。同时，双壁钢围堰的使用方法有了新的变化，已不局限于先将双壁钢围堰下沉就位 封底混凝土，接着施工钻孔桩，最后再抽水施工桩基承台这一传统施工工艺了。 现在有些做法已改成先施工钻孔桩，用钻孔桩的钢护筒，作为双壁钢围堰定位下沉的导向、支撑装置， 最后再做混凝土封底、抽水施工桩基承台。杭州下沙大桥即是如此。 三.论文的主要工作： (1)结合工程实际，根据有关规范规定，确定双壁钢围堰的主要尺寸各施工工况荷载计算 工况一：双壁钢围堰壁腔在水下封底混凝土未灌注前 工况二：双壁钢围堰壁腔在水下封底混凝土灌注完毕后 (2)钢围堰面板、竖肋、环板、横向桁架及封底混凝土设计，保证其强度、稳定性方面的要求 (3)围堰抗滑移、抗倾覆稳定性验算及抗浮稳定性验算 (4)围堰加工及下沉施工工艺 四.论文采用的方法手段： (1)查阅相关资料，依据有关规范进行设计运用结构力学及相关知识对各施工工况下的结构构件进行简化计算 (2)运用Midas有限元软件对双壁钢围堰进行精确计算 五.预期达到的结果： (1)双壁钢围堰设计任务书一份 (2)双壁钢围堰总体布置图A3图纸一张及施工图3张 (3)各节围堰施工工艺一份 (4)不少于3000字与桥梁有关的外文翻译 指导教师签字 时 间 年 月 日 6

摘 要

近年来我国修建了不少跨越大江大河甚至跨越海湾的深水基础，取得了很大的成绩。桥梁深水基础往往处于水深流急，地质条件极其复杂的环境，修建深水基础时采用的防水技术一般就是围堰和钢吊箱。双壁钢围堰具有结构强度高，防水性能好的特点，在桥梁深水基础中得到了广泛应用，并且它能承受较大的水压力，结构简单，施工简便。本设计就是对围堰进行结构和施工的设计。

根据承台尺寸(10m?10m)及水深(8m)拟定围堰结构尺寸，在不同的施工工况荷载作用下对围堰的刃脚、壁板、竖肋、隔舱板、水平桁架等围堰各组成部分进行受力分析和验算，若不合格重新拟定尺寸，然后运用MIDAS有限元分析软件对围堰建模进行整体计算并将结果与手算结果进行对比分析，最后合理确定围堰分节下沉的施工方案。

关键词：深水基础 双壁钢围堰 有限元分析 施工方案

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Abstract

In recent years many deep water foundations overcrossing great rivers even the bay are constructed in China and reach great achievement.Bridge deep water foundation is usually in the environment of deep water, torrent and complicated geographic condition.At the general situation cofferdam and steel hanging box are used to construct the deep water foundations with the function of waterproof performance . The double-wall steel cofferdam is widely applied in bridge deep water foundation due to that it is of characteristics of high structural strength and good waterproof performance and the double-wall steel cofferdam can bear major water pressure with simple structure and convenient construction.The content of this paper is the design of structure and construction of confferdam.

The structural dimension of confferdam is decided according to the cap size (10m?10m)and the depth of water(8m).The stress of component of cofferdam including edge foot , wainscot, vertical stiffening rib,compartment ,horizontal truss are analyzed and checked up under the action of different construction behaviour loads.

The dimension must be study out again if the stress is cheked up to be ineligible.The finite element analysis software MIDAS is used to model the confferdam for holistic computation,then the result is compared with the result of manual calculations for contrastive analysis.Finally the construction scheme of stepped subsiding is determined in reason.

Key words: deep water foundations double-wall steel confferdam finite element

analysis construction scheme

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目 录

第1章 绪论 ....................................................................................................................... 1 1.1 国内外现状 ............................................................................................................... 1 1.2 工程背景 ................................................................................................................... 4 1.3 钢围堰施工工艺简介 ............................................................................................... 5 1.4 双壁钢围堰受力分析 ............................................................................................... 8 第2章 围堰结构设计——结构力学方法 ....................................................................... 9 2.1 围堰构造 ................................................................................................................... 9 2.2 设计荷载 ................................................................................................................. 10 2.2.1 荷载种类 .......................................................................................................... 10 2.2.1.1 流水压力 .................................................................................................... 10 2.2.1.2 静水压力 .................................................................................................... 10 2.2.1.3 波浪力 ........................................................................................................ 11 2.2.1.4 土压力 ........................................................................................................ 11 2.2.2 计算工况 .......................................................................................................... 12 2.3 结构设计 ................................................................................................................. 12 2.3.1 荷载组合 .......................................................................................................... 12 2.3.2 围堰总体尺寸拟定 .......................................................................................... 12 2.3.3 工况1设计 ...................................................................................................... 13 2.3.3.1 隔舱板尺寸 ................................................................................................ 13 2.3.3.2 土压力计算 ................................................................................................ 14 2.3.3.3 每个隔舱板的抗弯能力计算 .................................................................... 15 2.3.3.4 竖向隔舱钢板工字型组合梁加劲肋布置 ................................................ 15 2.3.4 工况2设计 ...................................................................................................... 15 2.3.4.1 荷载计算 .................................................................................................... 15 2.3.4.2 隔舱板受力检算 ........................................................................................ 16 2.3.4.3 内支撑受力检算 ........................................................................................ 17 2.3.4.4 水平环板受力检算 .................................................................................... 18 2.3.4.5 水平桁架的斜杆受力计算 ........................................................................ 20 2.3.4.6 加劲肋受力验算 ........................................................................................ 21

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2.3.4.7 面板折算应力验算 .................................................................................... 22 2.3.4.8 检算悬臂根部应力 .................................................................................... 22 2.3.4.9 检算承台浇筑完成后可否拆除内支撑 .................................................... 24 2.4 围堰整体抗浮验算 ................................................................................................. 25 2.4.1 围堰下沉系数计算 .......................................................................................... 25 2.4.1.1 计算围堰自重 ............................................................................................ 25 2.4.1.2 计算钢围堰所受浮力 ................................................................................ 26 2.4.1.3 计算围堰与土体摩阻力 ............................................................................ 27 2.4.2 竖向抗浮力计算 .............................................................................................. 27 2.4.2.1 钢围堰自重 ................................................................................................ 27 2.4.2.2 竖向抗浮力计算 ........................................................................................ 27 2.4.3 封底混凝土强度验算 ...................................................................................... 27 2.3.3.1 封底混凝土弯曲应力验算 ........................................................................ 27 2.4.3.2 封底混凝土抗浮力验算 ............................................................................ 28 第3章 围堰施工工艺 ..................................................................................................... 29 3.1 围堰加工工艺 ......................................................................................................... 29 3.2 双壁钢围堰的锚碇系统布置 ................................................................................. 30 3.2.1 锚型选择 .......................................................................................................... 30 3.2.2 锚重计算 .......................................................................................................... 31 3.2.3 锚锭系统布置简介 .......................................................................................... 31 3.3 围堰接高 ................................................................................................................. 34 3.4 围堰下沉工艺 ......................................................................................................... 34 3.5 封底混凝土施工 ..................................................................................................... 35 3.5.1 围堰的封底厚度分析 ...................................................................................... 35 3.5.2 封底混凝土施工工艺 ...................................................................................... 36 3.5.2.1 围堰封底 .................................................................................................... 36 3.5.2.2 封底后抽水 ................................................................................................ 37 第4章 围堰结构设计——有限元分析方法 ................................................................. 38 4.1 有限元分析方法简介 ............................................................................................. 38 4.2 围堰有限元模型 ..................................................................................................... 39 4.2.1 单元类型 .......................................................................................................... 39 4.2.2 约束类型 .......................................................................................................... 42 4.2.3 荷载施加 .......................................................................................................... 42

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