Study On Construction Technology Of Large Diameter Rotary Pile For Building Engineering

With the increasing number of super high-rise buildings,higher requirements are put forward for building foundation engineering.Large diameter cast-in-place piles with high bearing capacity are gradually applied in building construction.Large diameter rotary excavation piles are difficult to drill and clear holes,and large diameter rotary excavation piles are more likely to cause collapse and pile quality defects than ordinary diameter rotary excavation piles.It is of great significance to study the construction technology of large diameter rotary excavation piles in depth.This paper studies the difficulties and difficulties in the construction of large diameter rotary excavation pile and ordinary rotary excavation pile,including the key links of judging the specific geological conditions of pile position,making and embedding of protective barrel,controlling mud parameters,drilling technology,making and installing of large diameter steel cage,selection of clearing mode,selection of hopper and conduit,etc.In-depth analysis.On the basis of the above research,by comparing the corresponding construction process of D2600 mm rotary excavation pile and D1200 mm rotary excavation pile in Foshan Zongde Service Center Project,the paper analyses the key difficulties and corresponding measures in construction technology and quality control of large diameter rotary excavation pile.The results of in-depth study on each working procedure of large diameter rotary excavation pile and its engineering application show that in the construction process of large diameter rotary excavation pile in construction engineering,the following links need to be controlled emphatically: in terms of slurry allocation,chemical slurry with high proportion and colloid ratio should be adopted to improve the stability of retaining wall and the requirement of hole cleaning stage.Slag-carrying capacity;when drilling into rock,it is impossible to form one-time according to the designed pile diameter,it is necessary to adopt graded reaming drilling technology;in the second hole cleaning,it is necessary to adopt air-lift reverse circulation or pump-suction reverse circulation hole cleaning technology;in the concrete pouring,it is necessary to adopt double or large diameter pipe casting and so on.In this paper,the key construction technology of large diameter rotary excavation pile is deeply studied,which can provide reference for the construction of large diameter rotary excavation pile.