【正文】 drilling pile maximum diameter of pile has reached 4000mm, maximum deep pile has reached 104m, and the steel pipe pile maximum diameter of 1200mm, the largest pile of prestressed concrete pipe pile with deep 83m, maximum diameter of 1300mm, the biggest pile depth 40m. Along with our country socialist construction is booming, with highrise buildings, large span bridges on the rise, the bearing capacity of pile foundation with higher requirements. Large diameter bored pile therefore gets rapid development, pile length and pile diameter also do bigger more. However, in the existing various methods of pile, bored pile has many advantages and is widely used in construction, but it is hard to avoid the impact of mud, which not only reduces the bearing capacity of pile expectations, but also caused a serious waste of materials. Manual hole digging pile is difficult to achieve greater depth, its bearing capacity is also difficult to just as one wishes. In view of bored pile in this situation, how to improve the pile construction technology level, make the input material to be more reasonable to use, so as to greatly increase the bearing capacity of single pile in engineering field, have bee hot issues in recent years. The introduction of bored castinplace pile Perfusion pile refers to the construction site by mechanical drilling, steel pipe soil paction or human mining method in the foundation pile hole in form, and on its inner placed reinforcement cage, concrete made with different pile, drilling method, grouting pile can be divided again for castinplace pile, bored pile and digging several types of piles. Bored pile by pile into the definition and classification of a kind of pile. The characteristics of bored castinplace pile And sinking pile of hammering method, construction noise and vibration is smaller To construct than the precast pile of large diameter of pile In all kinds of ground can be used The construction quality of the pile bearing capacity influence Because the concrete is in the mud perfusion is difficult to control, so the quality of concrete Bored pile construction method Percussion drilling, punching grabbing drilling and rotary drilling hole can adopt slurry wall construction method. The construction process is: site formation, slurry preparation, buried tube and laying work platform rig and positioning, drilling, hole cleaning and inspection of hole quality and lower steel cage, underwater concrete perfusion to pull out the barrel to check quality. Construction sequence： (1) the construction preparation Construction preparation prise: selecting drill, drill, layout. Construction of bored pile drilling rig is the main equipment, according to the geological conditions and various drilling machine applied to select conditions (2) drilling machine installation and positioning Istallation of drilling machine based if not stable, easy to produce in the drilling machine construction, pile and pile inclined inclined eccentric and other adverse effects, therefore requires the installation of foundation stability. On the formation of softer, sloping ground, be bulldozed, the pad plate or tie reinforcement. In order to prevent the pile position allowed, construction is very important to the set the center p