Several common pile foundations and pile driving techniques
At the bottom of the drill bit, when rotating, the soil layer becomes loose and becomes slag. It is suspended by mud and overflowed with mud. The well wall is protected by water head and mud. Reverse circulation rotary drilling: the mud flows into the borehole from the mud pool and is mixed with drilling slag. Suction role in vacuum pump, drill into a slag mixture into the mouth, through the drill pipe, and a slurry pump debris control raft excreted into the sedimentation tank cleaning, for further use. Because the bore diameter of drill pipe is much smaller than that of well bore, the water slurry in drill pipe is increased by 4~5 times faster than that of positive circle, and it is dominant in drilling hole of bridge drilling pile.
Bored pile foundation construction - long spiral drilling bored pile construction, the main processes are: site preparation, the laying of protective cylinders, preparation of mud, drilling, cleaning, reinforcement cage, into the hole and pouring underwater concrete. The key is drilling, the main methods are: rotating method, impact method and punching method. The rotary drilling can be divided into positive revolving drilling, reverse circulation rotary drilling, long spiral drilling machine and so on. Bored pile foundation construction - reverse and reverse rotating drilling, positive rotation drilling: mud from the mud pump at high pressure from the mud tank into the bore of the drill pipe, the drill hole through the mouth of the injection.
Sinking into the pile foundation - Hammer Sinking Pile into the pile, the main construction methods are: Hammer Sinking Pile, vibration pile, static pressure pile and immersed pipe pile. The hammer sinking pile is generally applicable to medium density sand soil and cohesive soil. Because the pile driving hammer will sink the pile and hit the pile against the impact energy of the pile hammer, so the general pile diameter can not be too large (not more than 0.6m), and the buried depth is not greater than 50m. Sinking pile foundation pile, cast-in-place pile is the reinforced concrete or steel pipe pile tip with valve pile tip at the bottom of the sleeve, sinking to the required depth by hammering or vibration, the tube placed inside the reinforcement cage, concrete pouring, pull out pipe forming.
