鉆孔前的準備工作主要包括樁位放樣，整理平整場地，布設施工便道，設置供電及供水系統(tǒng)，制作和埋設護筒，制作鉆孔架，泥漿的制備和準備鉆孔機具等。
§3.2.1-1 場地整理
施工前，施工場地按不同情況進行處理。對于處在水中的鉆孔樁基礎都必須搭設施工平臺，樁基處在旱地時，清除雜物后夯壓密實即可。
§3.2.1-2 本標段鉆孔樁均使用鋼護筒，采用3mm-5mm鋼板制作。
為保證其剛度，防止變形，在護筒上、下端和中部外側各焊一道加勁肋。本合同段的鉆孔樁直徑為ф120cm和100cm。根據(jù)鉆孔樁直徑，我們所做的護筒直徑為145cm和125cm。護筒埋設時，其軸線對準測量所標出的樁位中心，護筒周圍和護筒底接觸緊密，保證其位置偏差不大于5cm，傾斜度不大于1%。
§3.2.1-3 泥漿的制作
制漿前，先把粘土盡量打碎，使其在攪拌中容易成漿，縮短成漿時間，提高泥漿質量。制漿時，可將打碎的粘土直接投入護筒內(nèi)，使用沖擊錐沖擊制漿，待粘土已沖攪成泥漿時，即可進行鉆孔。多余的泥漿用管子導入鉆孔外泥漿池貯存，以便隨時補充孔內(nèi)泥漿。
§3.2.1-4 鉆機就位
埋設好護筒后，即可進行鉆機就位，本標段使用的鉆機為卷揚機牽引式?jīng)_擊鉆和沖抓鉆。就位時，只要使鉆錐中心對準測量放樣時所測設的樁位即可，其對中誤差不得大于5cm。
§3.2.2 鉆孔工藝
§3.2.2-1 沖擊鉆鉆孔工藝
Preparation before drilling include Pile Layout, finishing leveling the ground and laid pavement construction, power supply and set up water supply, production and laying of casing, production drilling frame, drilling mud preparation and preparation equipment, etc..
§ 3.2.1-1 site preparation
Before the construction, construction site under different processing conditions. Bored piles for the foundation in the water must be erection construction platform, when the pile is in dry, clear debris after the compacting compaction can be.
§ 3.2.1-2 of the tenders bored piles are used steel casing, with 3mm-5mm steel plate production.
In order to ensure its rigidity against deformation in the casing, the bottom and outside of the welding a central stiffener. Paragraph of this contract ф120cm diameter bored piles and 100cm. According to the diameter bored piles, we do pipe diameter is 145cm and 125cm. Casing, its axis aligned measurements Pile marked center of casing and casing around the end of close contacts to ensure its position deviation is less than 5cm, less than 1% gradient.
§ 3.2.1-3 production of mud
Pulp before, first try to break the clay, it is easy to stir into the pulp slurry reduced time and improve the quality of mud. Pulp, can be broken clay barrel directly into care, the impact of using the shock cone pulp, until the clay has been washed Jiaocheng mud, they can be boring. Excess drilling mud outside the mud with a tube into the storage pool so that at any time to add the mud hole.
§ 3.2.1-4 rig in place
After laying well casing can be rig in place, the tenders for the hoist rig used in drilling and the red tractor grasp the impact of drilling. Place, as long as drill and center aligned to the time of survey and setting out survey and design of pile-bit can be, their error of not more than 5cm.
§ 3.2.2 Holes
§ 3.2.2-1 percussion drill technology

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