【正文】 開挖過程中發(fā)現(xiàn)圍護(hù)體接縫處滲水應(yīng)及時(shí)采取封堵措施。 土方開挖 1）基坑挖土分層、分塊開挖，隨挖隨打墊層。 4）坑底做盲溝，隨挖隨填，與降水井相連形成坑底明排水系統(tǒng)。 2）施工底板前先封井做法：去除坑底標(biāo)高以上無砂砼管，填碎石，澆注 C15厚0m砼封堵井口。 3）向上施工地下室結(jié)構(gòu)，施工至地下室頂板結(jié)構(gòu)。 設(shè)計(jì)工況 1）施工圍護(hù)樁、止水帷幕，降水井、結(jié)構(gòu)工程樁等。 3）基坑開挖期應(yīng)著重檢查開挖面滲漏水情況，如不符合設(shè)計(jì)要求應(yīng)立即采取必要的補(bǔ)救措施，以防止出現(xiàn)工程事故。 2）三軸水泥土攪拌樁采用 ，水泥摻入比 20%，水灰比 ，外摻劑由施 工單位根據(jù)本場地地質(zhì)情況和經(jīng)驗(yàn)確定。 4）鉆孔樁施工之前應(yīng)先探明每根樁樁位處有否地下障礙物及市政管線，如有障礙物必須對其清理及回填素土（不得含有塊石和生活垃圾），分層夯實(shí)后方可進(jìn)行圍護(hù)樁施工。主筋接頭間距應(yīng)≥ 1200,并在同一連接區(qū)段內(nèi)的接頭不得多于總數(shù)的 50％，箍筋采用螺旋箍。 鉆孔灌注樁 1）本工程局部選用直徑 80m的鉆孔灌注樁作為圍護(hù)結(jié)構(gòu)；孔灌注樁樁頂設(shè)置鋼筋混凝土壓頂梁。基坑地下兩層區(qū)域，基坑開挖深度 ~。 2）本工程177。 第 1 頁 共 58 頁 目錄 一、方案編制依據(jù) ............................................................................................................ 3 .................................................................................................. 3 ..................................................... 4 ..................................................................................................... 5 、規(guī)程 ............................................................................. 5 二、工程概況 ................................................................................................................... 6 ............................................................................................................ 6 .................................................................................................. 6 .............................................................................................. 8 ............................................................................................ 17 ................................................................................................... 21 ................................................................................................... 21 、重點(diǎn)和關(guān)鍵點(diǎn) ....................................................................... 22 、人員配置及職能 ................................................................ 22 ................................................................................................... 24 三、土方開挖 ................................................................................................................. 25 ....................................................................................................... 25 .......................................................................................................... 26 ................................................................................................... 32 ....................................................................... 34 、集水坑開挖方法 .................................................................................. 34 ................................................................................................................. 34 四、降水施工方案 .......................................................................................................... 34 .......................................................................................................... 34 ....................................................................................................... 34 .......................................................................................................... 38 ......................................................................................... 39 ......................................................................................... 39 ................................................................ 39 .................................................................... 40 ............................................................................................ 40 ................................................................................................... 40 五、周邊建筑物的保護(hù)方案 ............................................................................................ 42 ....................................................................................................... 42 .......................................................................................................... 42 六、基坑監(jiān)測方案 .......................................................................................................... 44 監(jiān)測單位及編制依據(jù) ........................................................................................ 44 ................................................................................................ 44 ....................................................................................................... 44 .......................................................................................................... 45 .......................................................................................................... 45 ....................................................................................................... 46 第 2 頁 共 58 頁 .......................................................................................................... 46 .......................................................................................................... 49 布置圖 .................................................................................................. 50 七、基坑風(fēng)險(xiǎn)應(yīng)急預(yù)案 ................................................................................................... 52 預(yù)防措施 .......................................................................................................... 52 應(yīng)急措施 .......................................................................................................... 52 .......................................................................................................... 52 .......................................................................................................... 54 八、季節(jié)性施工措施 ..................................................................