預應力薄壁管樁螺旋鉆土糾偏施工工藝.doc

預應力薄壁管樁螺旋鉆土糾偏施工工藝

一、基本情況
某工程為框架七層，總長度為78.98m，總寬度為66.01m，建筑面積為17135㎡，分為A1，A2，A3棟，中間以裙樓相連，主樓與裙樓間設有后澆帶和伸縮縫，按七度抗震設計,框架抗震等級為三級。
土質情況：根據地質報告反應，第一層為素填土，層厚0.30—1.80m，第二層為粉質粘土，層厚0.60—2.45m，第三層為淤泥質粘土，層厚14.00—25.50m，第四層為淤泥質粘土，層厚為1.90—6.90m，第五層為粘土，層厚為6.50—27.10m。
工程采用Ǿ400、 Ǿ550預應力薄壁管樁，樁長32m，采用靜壓成樁，施工后，經動測發現部分管樁上部斷裂，樁頂嚴重偏位，最大偏位量達到610mm，為利用下部管樁的承載力需將上部斷樁復位，然后在管樁內筒中澆灌配筋砼進行接樁補強。經對幾種糾偏復位方法進行試驗比較，最后選定螺旋鉆取土糾偏施工方案。
二、取土糾偏專用工具
1、螺旋鉆：由鉆桿、螺旋葉片、轉動手柄及連接件構成。鉆桿的長度由鉆孔深度要求確定，鉆桿應能抵抗轉動時產生的扭矩，本工程使用鉆桿
Prestressed thin-walled spiral drill pipe construction technology soil correction

I. Basic
The framework of a project to seven, with a total length of 78.98m, total width of 66.01m, a building area of 17,135 square meters, divided into A1, A2, A3 Building, connected to the middle in order to skirt the main building is equipped with the podium after the pouring and expansion joints, seismic design by 7 degrees, frame seismic rating of 3.
Soil conditions: According to the geological report reaction, the first layer filling factor, thickness 0.30-1.80m, the second layer of clay, thickness 0.60-2.45m, the third layer is silty clay, thickness of 14.00- 25.50m, silty clay, the fourth layer, thickness is 1.90-6.90m, the fifth layer of clay, with the thickness 6.50-27.10m.
Works with Ǿ400, Ǿ550 prestressed thin-walled pipe, pile length 32m, using static pile, after construction, by the dynamic testing found that some of the upper pipe rupture, a serious deviation pile head, the maximum deviation amounted to 610mm, for the use of the lower part of the bearing capacity of pipe piles need to reset the top off, then the inner cylinder in the water in the pipe reinforced concrete for the pile reinforcement. The reduction of several methods of correcting experimental comparison, the final selection of spiral drill dug rectification construction program.
Second, take soil correction special tools
1, spiral drill: the drill pipe, spiral blades, turn the handle and connector form. The length of drill pipe to determine the drilling depth required, the drill pipe should be able to resist the torque generated during rotation, the use of drill pipe works
 

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