1. Introduction to construction method
The casing rotator is a new type drill with the integration of the full hydraulic power and transmission, and
the combination control of machine, power and fluid. It is a new, environmentally-friendly and highly efficient drilling technology. In recent years, it is widely adopted in the projects such as
the constructions of urban subway, articulation pile of deep foundation pit enclosure, clearance of waste
piles ( underground obstructions ), high-speed rail, road and bridge, and urban construction piles, as well
as the reinforcement of reservoir dam.
The successful research of this brand new process method has realized the possibilities for the
construction workers to conduct the construction of casing pipe, displacement pile, and underground
continuous wall, as well as the possibilities for the pipe-jacking and shield tunnel to pass through the
various pile foundations without barriers, when the obstructions, such as the gravel and boulder formation,
cave formation, thick quicksand stratum, strong necking down formation, various pile foundation and steel
reinforced concrete structure, are not removed.
The construction method of casing rotator has successfully completed construction missions of more than
5000 projects at places of Singapore, Japan, Hongkong District, Shanghai, Hangzhou, Beijing and Tianjin.
It certainly will play a bigger role in the future urban construction and other pile foundation construction
( 1 ) Foundation pile, continuous wall:
l Foundation piles for high-speed rail, road and bridge and house building.
l Articulation pile constructions which are required to be excavated, such as subway platforms,
underground architectures, continuous walls
l Water retaining wall of reservoir reinforcement.
( 2 ) Drilling gravels, boulders and karst caves
l It is allowable to conduct the foundation pile construction at mountain lands with gravel and boulder
l It is allowable to conduct operation and cast the foundation piles at he thick quicksand formation and
necking down stratum or the filling layer.
l Conduct rock-socketed drilling to the rock stratum, cast the foundation pile.
( 3 ) Clear the underground obstructions
l During the urban construction and bridge rebuilding, the obstructions such as the steel reinforced
concrete pile, steel pipe pile, H steel pile, pc pile and wood pile can be cleared directly, and cast the
foundation pile on the spot.
( 4 ) Cut the rock stratum
l Conduct the rock-socketed drilling to the cast-in-place piles.
l Drill through-holes on the rock bed (shafts and ventilation holes)
( 5 ) Deep excavation
l Conduct the in-place casting or steel pipe pile inserting for the deep foundation improvement.
l Excavate deep wells for construction use in the constructions of reservoir and tunnel.
2. The advantages of adopting the casing rotator for construction
1) No noise, no vibration, and high safety;
2) Without mud, clean working surface, good environmental friendliness, avoiding the possibility for
mud to enter the concrete, high pile quality, enhancing the bond stress of concrete to the steel bar;
3) During construction drilling, the characteristics of stratum and rock can be directly distinguished;
4) The drilling speed is fast and reaches about 14m/h for the general soil layer;
5) The drilling depth is large and reaches about 80m according to the situation of soil layer;
6) The hole forming verticality is easy to master, which can be accurate to 1/500;
7) No hole collapse will be caused, and the hole forming quality is high.
8) The hole forming diameter is standard, with little filling factor. Being compared with other hole
forming methods, it can save a lot of concrete usage;
9) The hole clearing is thorough and fast. The drilling mud at the hole bottom can be clear to about