【正文】 圖 15 先下鋼圍堰后施工鉆孔樁方案流程圖 (2)先成樁后施工鋼圍堰方案 先成樁后施工鋼圍堰具有以下優(yōu)點(diǎn)： ① 施工快，從施工鉆孔平臺(tái)鋼管樁、架設(shè)平臺(tái)至開(kāi)鉆時(shí)間短； ② 可降低鋼圍堰高度，節(jié)省工期，降低造價(jià)；減少雙壁鋼圍堰夾壁混凝土量； ③ 避免巖面高低不平時(shí)，鋼圍堰不規(guī)律的高低刃腳著巖難度； ④ 清除鉆渣 難度減少； 石家莊鐵道學(xué)院畢 業(yè)設(shè)計(jì) 7 鋼管樁制作 平臺(tái)拼裝 施打鋼管樁 搭設(shè)鉆孔平臺(tái) 下沉鋼護(hù)筒 鉆孔樁施工 施工平臺(tái)拆除 首節(jié)鋼圍堰安裝 圍堰接高 (下沉 ) 圍堰封底 干施工承臺(tái) 鋼圍堰制作 ⑤ 封底混凝土量可減少。從施工方面看，鉆孔灌注樁基礎(chǔ)的施工有分為先下鋼圍堰后成樁和先成樁后下鋼圍堰兩種施工方案。 工程背景 某 橋梁深水承臺(tái)雙壁鋼圍堰 ，水深 8m，承臺(tái)為正方形，尺寸 10m 10m? ， 厚 3m，河床為密實(shí)細(xì)砂。鋼板樁雙壁鋼圍堰作為雙壁鋼圍堰的一種類(lèi)型在歐洲和美洲，以及亞洲的日本和中國(guó)的臺(tái)灣地區(qū)應(yīng)用最為廣泛。圍堰下沉到基巖后，對(duì)圍堰底面進(jìn)行支墊并采用外鋼插板堵漏，確保圍堰穩(wěn)定并防止封底混凝土外漏。封底厚度設(shè)計(jì)為 7m，為了使圍堰在無(wú)嵌巖樁的情況下安全渡洪，實(shí)際封底厚度為 。 黃石長(zhǎng)江大橋主橋?yàn)?+3245m+。 溫州甌江二橋主橋?yàn)殡p塔雙索面預(yù)應(yīng)力混凝土斜拉橋，主孔跨徑 270m。此外，還可節(jié)約了原鋼圍堰下沉過(guò)程中處理涌砂、漏水等問(wèn)題產(chǎn)生的費(fèi)用。該橋原方案鋼圍堰需下沉人土 6m，圍堰下沉占用工期時(shí)間 90d，再水中混凝土封底、鉆孔樁施工，接著干法施工承臺(tái)。同時(shí)。 蚌埠市朝陽(yáng)淮河公路大橋利用高壓旋噴 樁豎直帷幕止水技術(shù)加固地基 ，減少大型雙壁鋼圍堰人土深度進(jìn)行水中承臺(tái)施工的 技術(shù) 則是另一成功的范例。 雙壁鋼圍堰外型尺寸見(jiàn)圖 12。同時(shí)，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(tái)這一傳統(tǒng)施工工藝了。湖北省軍山長(zhǎng)江公路大橋主橋?yàn)?48m+204m+460m+204m+48m的五跨連續(xù)雙塔雙索面半漂浮石家莊鐵道學(xué)院畢 業(yè)設(shè)計(jì) 2 體系鋼箱梁斜拉橋。這不僅有利干設(shè)備的利用，還能重復(fù)使用雙壁鋼圍堰的上部，可充分發(fā)揮材料的利用率，降低成本，也便于施工管理。雙壁鋼圍堰施工的優(yōu)勢(shì)是深水、巖石河床，并且河床覆蓋層薄，這樣。 橋梁基礎(chǔ)雙壁鋼圍堰施工技術(shù)就是深水施工中的一種新技術(shù)。 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 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(guó)內(nèi)外現(xiàn)狀 ............................................................................................................... 1 工程背景 ................................................................................................................... 4 鋼圍堰施工工藝簡(jiǎn)介 ............................................................................................... 5 雙壁鋼圍堰受力分析 ............................................................................................... 8 第 2 章 圍堰結(jié)構(gòu)設(shè)計(jì) —— 結(jié)構(gòu)力學(xué)方法 ....................................................................... 9 圍堰構(gòu)造 ................................................................................................................... 9 設(shè)計(jì)荷載 ................................................................................................................. 10 荷載種類(lèi) .......................................................................................................... 10 流水壓力 .................................................................................................... 10 靜水壓力 .................................................................................................... 10 波浪力 ........................................................................................................ 11 土壓力 ........................................................................................................ 11 計(jì)算工況 .......................................................................................................... 12 結(jié)構(gòu)設(shè)計(jì) ................................................................................................................. 12 荷載組合 .......................................................................................................... 12 圍堰總體尺寸擬定 .......................................................................................... 12 工況 1 設(shè)計(jì) ...................................................................................................... 13 隔艙板尺寸 ................................................................................................ 13 土壓力計(jì)算 ................................................................................................ 14 每個(gè)隔艙板的抗彎能力計(jì)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(jì) ...................................................................................................... 15 荷載計(jì)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(jì)算 ........................................................................ 2