Hollow pile and solid pile of steel screw pile

The hollow pipe joint of reinforced concrete is turned by a special steel hook inside the pile body. The torque of the winch is transmitted horizontally to the pile at the rotor blade.
In order to increase the strength of the pile body, the hollow pipe joints must be made of prestressed reinforced concrete. Because of the complexity of manufacturing and twisting, hollow reinforced concrete spiral pile has not been used so far.
Reinforced concrete screw pile with solid section, its structure is relatively simple, this kind of pile is made of ordinary concrete with high strength, the grade of concrete is 300~400 kg/cm 2, and the standing steel sleeve is twisted on the screw pile.
This type of reinforced concrete screw pile was used for the first time in the construction of a bridge in 1951~1952. The pile is approximately 500 mm in diameter and is made of 300-grade concrete. Pile boots are made of cast iron. Its rotor blades are 1.5 meters in diameter. The sinking depth of the pile is about 8 meters. The average rate of subsidence in the soil is between 7 and 8 meters per hour. Sinking - The total time of the 8.5-9 meter long screw pile, including all the preparation work, is less than 4 hours.
On another bridge, the same reinforced concrete spiral pile is used, and its sinking depth is greater than 17 meters. The pile is an 8-angle solid section with an outer circle diameter of 4.50 mm. The concrete is 300 grade. The pile shoe is made of steel material and its rotor blades are triangular in section. The leaf diameter is 1.4 m. All screw piles are sunk into the soil at different speeds at inclines ranging from 5:1 to 5.5:1. The maximum speed of the screw pile is 13~13.5 meters/hour. Minimum speed; Only one pile has such a speed, about 3 meters per hour. The average sinking speed is 7.6 m/h. The screw piles used in both Bridges were screwed in with the Central Academy of Sciences' 1945 winch.
The construction organization of the two Bridges is much the same. The torsional moment used by each pile is 30 to 35 tons/m, which is transferred from the winch to the pile shoe through the standing casing. When the pile shoe and pile body are sunk, the standing steel sleeve is pulled out of the soil for the next screw pile.