泥漿護壁回轉鉆孔灌注樁工程技術交底.doc

一、 工程概況
廣東科學中心主樓工程樁樁徑分為φ800和φ1000兩種，其中樁徑為φ800的樁共404條；樁徑為φ1000的樁共685條。工程樁樁端持力層為中風化泥質粉砂巖，樁端進入持力層深度為1.5～5米。采用正循環工藝成孔和清孔，樁垂直度偏差要求不大于1％，樁徑偏差要求不得超過－50mm，灌注混凝土前孔底沉渣厚度要求不大于50mm。
樁身采用C35水下混凝土，混凝土保護層厚度為70mm，混凝土的防腐等級為一級防護，采用普通硅酸鹽水泥。
二、 質量標準
1、 保證項目
（1） 灌注樁用的原材料和混凝土強度必須符合設計要求和施工規范的規定。
（2） 成孔深度必須符合設計要求，樁端持力層為中風化泥質粉砂巖，樁端進入持力層深度應≥hr（入巖深度）；遇軟弱夾層時必須穿越軟弱夾層。
（3） 樁身材料：混凝土等級為C35，為水下混凝土；鋼筋HPB235級，HRB335級�？v筋的混凝土保護層厚度為70mm�；炷�土最大水灰比為0.45（可加減水劑），最小水泥用量為360kg/m3，鋁酸三鈣含量≤8％，最大氯離子含量為0.06％，最大堿含量為3.0kg/m3。
（4） 分段鋼筋籠中的縱筋采用搭接焊接長，單面搭焊10d；縱向鋼筋接頭應每隔一根錯開，同一截面可接長50％的總鋼筋面積的鋼筋，相鄰接頭錯開1000mm；螺旋箍筋與縱筋點焊，螺旋箍筋采用單面搭接焊10d接長。
First, project survey
Guangdong Science Center main building works is divided into φ800 and φ1000 pile diameter two, which piles the pile diameter φ800 of 404; pile diameter φ1000 total of 685 piles. Engineering pile tip bearing layer of weathered pelitic siltstone, pile into the support layer of depth is 1.5 to 5 meters. Circulation process by being clear hole and the hole, pile verticality deviation requirement is less than 1% deviation required pile diameter shall not exceed-50mm, the pouring of concrete required before the hole bottom sediment thickness is less than 50mm.
C35 underwater pile with concrete, concrete cover thickness to 70mm, grade level concrete corrosion protection, using ordinary portland cement.
Second, quality standards
1, ensure that the project
(1) The pile of raw materials and the strength of concrete used must meet the design requirements and construction norms.
(2) into the hole depth must meet the design requirements, pile tip bearing layer in the weathered pelitic siltstone, pile into the bearing layer depth should be ≥ hr (into the rock depth); case of weak interlayer must be through the soft interlayer.
(3) Pile material: concrete grade C35, the underwater concrete; reinforced HPB235 level, HRB335 grade. Longitudinal reinforcement of the concrete cover thickness to 70mm. Maximum water-cement ratio of concrete was 0.45 (additive water reducing agent), the minimum amount of cement as 360kg/m3, tricalcium aluminate content of ≤ 8%, the maximum chloride ion content of 0.06% and the maximum alkali content of 3.0kg/m3.
(4) above the longitudinal reinforcement steel cage welded by lap length, single lap welding 10d; longitudinal steel joints should be staggered at intervals of 1, the same section can be accessed 50% of the total length of the steel reinforcement area adjacent joints stagger 1000mm; spiral reinforcement and longitudinal reinforcement welding, lap welding of spiral hoop with one side longer then 10d.
 

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