The advantages and disadvantages of the rotary drilling rig and impact drilling machine used in the construction of bridge bored pile foundation
Three see is a friction pile or pile support, support pile must use cyclotron drill, or go after drilling friction pile on the pile bottom sediment is not high, can be used to drill, but to ensure the aperture piles in Yangtze River bridge 3 meters are used for drilling rotary drill rig. Positive cycle rig. Reverse circulation drilling rig (pump suction or air lift). Full bore rig. Punching and drilling. Manual hole digging.... Have to look at geology, there are advantages and disadvantages, and pile diameter, the bottom water level, the amount of engineering, land or on the work rack, the length of the pile, and so on, ah!Rotary drill: wide range of application. That is, the mud wall, the hole is not easy. Drilling speed is slow in rock geology;
Most of the hard rock formations have little pile diameter and are mostly end bearing piles. Most of them are made of impact drilling. Some of them are excavated by hand, and the small hole is short. The majority of bridge piles are impacted. Encountered complex formations, the pile length is less than 40 meters, the most reliable is the use of impact drilling. A look at geology, two to see the quality, or positive and negative cycle drilling, good quality of the hole, steel dragon protection layer can guarantee
According to the different geological and different methods of land weak cyclotron drilling sand layer rapidly, large pile diameter long friction pile most belong to this kind of formation so almost all of the cyclotron drill.
