钻孔桩施工工艺.doc

钻孔前的准备工作主要包括桩位放样，整理平整场地，布设施工便道，设置供电及供水系统，制作和埋设护筒，制作钻孔架，泥浆的制备和准备钻孔机具等。
§3.2.1-1 场地整理
施工前，施工场地按不同情况进行处理。对于处在水中的钻孔桩基础都必须搭设施工平台，桩基处在旱地时，清除杂物后夯压密实即可。
§3.2.1-2 本标段钻孔桩均使用钢护筒，采用3mm-5mm钢板制作。
为保证其刚度，防止变形，在护筒上、下端和中部外侧各焊一道加劲肋。本合同段的钻孔桩直径为ф120cm和100cm。根据钻孔桩直径，我们所做的护筒直径为145cm和125cm。护筒埋设时，其轴线对准测量所标出的桩位中心，护筒周围和护筒底接触紧密，保证其位置偏差不大于5cm，倾斜度不大于1%。
§3.2.1-3 泥浆的制作
制浆前，先把粘土尽量打碎，使其在搅拌中容易成浆，缩短成浆时间，提高泥浆质量。制浆时，可将打碎的粘土直接投入护筒内，使用冲击锥冲击制浆，待粘土已冲搅成泥浆时，即可进行钻孔。多余的泥浆用管子导入钻孔外泥浆池贮存，以便随时补充孔内泥浆。
§3.2.1-4 钻机就位
埋设好护筒后，即可进行钻机就位，本标段使用的钻机为卷扬机牵引式冲击钻和冲抓钻。就位时，只要使钻锥中心对准测量放样时所测设的桩位即可，其对中误差不得大于5cm。
§3.2.2 钻孔工艺
§3.2.2-1 冲击钻钻孔工艺
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