【正文】 施工中的一種新技術(shù)。即雙壁鋼圍堰能在深水、厚覆蓋層的條件下采用； (4)雙壁鋼圍堰完全下沉就位后，不僅可作為鉆孔樁基礎(chǔ)的施工 輔助設(shè)施，也可作為大面積承載的直接基礎(chǔ)； (5)在同一座橋上，在不同地質(zhì)條件情況下，也可以用相同的施工方法修建深水基礎(chǔ)?，F(xiàn)在的雙壁鋼圍堰的高度累計可達 25m，寬度可達 30m，甚至更多。該雙壁鋼圍堰就是上述的第一種類型。同時，雙壁鋼圍堰的使用方法有了新的變化，已不局限 于先將雙壁鋼圍堰下沉就位 封底混凝土，接著施工鉆孔樁，最后再抽水施工樁基承臺這一傳統(tǒng)施工工藝了。橋梁深水基礎(chǔ)往往處于水深流急，地質(zhì)條件極其復(fù)雜的環(huán)境，修建深水基礎(chǔ)時采用的防水技術(shù)一般就是圍堰和鋼吊箱。 關(guān)鍵詞： 深水基礎(chǔ) 雙壁鋼圍堰 有限元分析 施工方案 Abstract In recent years many deep water foundations overcrossing great rivers even the bay are constructed in China and reach great deep water foundation is usually in the environment of deep water, torrent and plicated geographic the general situation cofferdam and steel hanging box are used to construct the deep water foundations with the function of waterproof performance . The doublewall 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 doublewall steel cofferdam can bear major water pressure with simple structure and convenient 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 ponent of cofferdam including edge foot , wainscot, vertical stiffening rib,partment ,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 putation,then the result is pared with the result of manual calculations for contrastive the construction scheme of stepped subsiding is determined in reason. Key words: deep water foundations doublewall steel confferdam finite element analysis construction scheme 目 錄 第 1 章 緒論 ....................................................................................................................... 1 國內(nèi)外現(xiàn)狀 ............................................................................................................... 1 工程背景 ................................................................................................................... 4 鋼圍堰施工工藝簡介 ............................................................................................... 5 雙壁鋼圍堰受力分析 ............................................................................................... 8 第 2 章 圍堰結(jié)構(gòu)設(shè)計 —— 結(jié)構(gòu)力學(xué)方法 ....................................................................... 9 圍堰構(gòu)造 ................................................................................................................... 9 設(shè)計荷載 ................................................................................................................. 10 荷載種類 .......................................................................................................... 10 流水壓力 .................................................................................................... 10 靜水壓力 .................................................................................................... 10 波浪力 ........................................................................................................ 11 土壓力 ........................................................................................................ 11 計算工況 .......................................................................................................... 12 結(jié)構(gòu)設(shè)計 ................................................................................................................. 12 荷載組合 .......................................................................................................... 12 圍堰總體尺寸擬定 .......................................................................................... 12 工況 1 設(shè)計 ...................................................................................................... 13 隔艙板尺寸 ................................................................................................ 13 土壓力計算 ................................................................................................ 14 每個隔艙板的抗彎能力計算 .................................................................... 15 豎向隔艙鋼板工字型組合梁加勁肋布置 ................................................ 15 工況 2 設(shè)計 ...................................................................................................... 15 荷載計算 .................................................................................................... 15 隔艙板受力檢算 ........................................................................................ 16 內(nèi)支撐受力檢算 ........................................................................................ 17 水平環(huán)板受力檢算 .................................................................................... 18 水平桁架的斜桿受力計算 ........................................................................ 20 加勁肋受力驗算 ........................................................................................ 21 面板折算應(yīng)力驗算 .................................................................................... 22 檢算懸臂根部應(yīng)力 .................................................................................... 22 檢算承臺澆筑完成后可否拆除內(nèi)支撐 .................................................... 24 圍堰整體抗浮驗算 ................................................................................................. 25 圍堰下沉系數(shù)計算 .......................................................................................... 25 計 算圍堰自重 ............................................................................................ 25 計算鋼圍堰所受浮力 ................................................................................ 26