英文篇名
A CASE STUDY OF 90M DEEP CYLINDER SHAPE SLURRY WALL CONSTRUCTION
作者
鍾毓東、陳成、余明山、柯允華
關鍵字
連續壁、端版、穩定液、脫水機械、廢液處理、強塑劑、特密管、完整性試驗、混凝土側壓、施工管理、混凝土強度
摘要
本文整理國內極特殊之90m深圓筒型連續壁案例,特別針對施工方法、工率及品質管理,加以紀錄分析。連續壁之混凝土強度,依深度由上而下依次為300kg/cm2、450kg/cm2及300kg/cm2三種強度,以承受隨壁體深度變化之彎矩,此設計觀念在國內極為罕見。分割單元中,公單元長度長達10m,仍能維持壁溝穩定,為本工程特色之一。開挖作業採用抓斗式MHL及鑽掘式BW兩種開挖機並用,對於開挖方法、接頭清洗及底泥清除方式,開挖效率與垂直精度,文中均詳加介紹;其中開挖垂直精度在千分之一以內,水準極高。穩定液在開挖過程中,扮演極重要角色,文中針對穩定液之配比、處理流程、品質檢驗、如何調整穩定液以節省成本、及如何處理廢液以達環保要求,均詳加闡述。同時,有關穩定液生產量及廢液處理使用之材料量相對於開挖土方量之比值,亦作整理,可做為成本分析之參考。其次,對於鋼筋籠吊裝及混凝土澆灌作業之方法及工率,亦加以詳實紀錄並統計。最後,探討混凝土之強度及其特性,發現現場鑽心取樣強度遠高於標準試體強度,平均比值約為125%~145%。
英文摘要
A case study of 90m-deep cylinder shape slurry wall construction, which break many local records of slurry wall construction, is illustrated in this article. The contents focus on the construction method, construction efficiency and quality control. The concrete strength along the depth of slurry wall, is designed to be 300kg/cm2, 450kg/cm2 and 300kg/cm2 corresponding to the variation of moment distribution. Such design concept is rare in local practice. Also an outstanding record of the construction is when the B element reaches 10m, the longest element ever used in local construction, the excavation trench remains stable. Both clam-shell type MHL machine and drilling type BW machine are utilized to excavate the same element at the different depths. The excavation sequence, joint cleaning, slime treatment, excavation efficiency and the vertical accuracy are described in detail. As commonly known, slurry always an important role in slurry wall construction, therefore part of this article is contributed to full discussion of the production procedure of slurry, which includes mixing proportion, quality control, quantity adjustment, and waste treatment. Mean while, the production of slurry, the material consumed for slurry and waste slurry treatment and the excavated soil volume of slurry wall are compared, so that the cost analysis and quality control can be refered in future projects related to slurry wall construction. In addition, a detailed record and statistics on the methods and efficiency of rebar cage insertion and concrete placing are also discussed in the article. In the end, the concrete strength and its characteristics are studied and it is found that the strength of the in-situ cored sample is higher than that of the cylinder sample with a mean ratio of 125%~145%.