Introduction to the construction scheme of rotary bored pile?

Construction scheme of rotary drilling bored pile? The following is the construction scheme of rotary bored pile brought by Zhong Da Consulting Company for reference only.

The construction scheme of rotary drilling cast-in-place pile has been developed for decades in the world, but it has only been gradually recognized and applied in China in the last four or five years, and has become a new pile hole construction method with the fastest development in recent years. Rotary bored pile technology is known as "green construction technology", which has the characteristics of high efficiency, good construction quality and less dust and mud pollution. Rotary drilling rig is a multifunctional and efficient drilling equipment for cast-in-place piles, which can realize automatic adjustment of mast verticality and measurement of drilling depth. Rotary excavation construction is to use the rotation of drill pipe and drill bucket, take the weight and hydraulic pressure of drill bucket as the WOB, fill the drill bucket with soil chips, and then lift the drill bucket off the ground. Through the rotation, excavation, lifting, soil unloading, mud replacement and wall protection of the drill bucket, holes are repeatedly formed. Hanging reinforcing cage, pouring concrete and post-grouting are equivalent to other underwater bored piles.

This method has a high degree of automation and high drilling efficiency, and the drill bit can quickly pass through various complex strata, which has a very broad prospect in pile foundation construction, especially in urban pile foundation construction.

The construction characteristics of rotary bored pile can be used in strata with high water level and large pebbles, but it can't be constructed by positive and negative circulation and long auger. High degree of automation, fast pore-forming speed and high quality.

The drilling rig is driven by full hydraulic pressure and controlled by computer, which can accurately locate the drilling hole, automatically correct the verticality of the drilling hole, automatically measure the drilling depth and ensure the drilling quality to the greatest extent. Its working efficiency is 20 times that of the circulating drilling rig, and most importantly, the quality and progress of the project are fully guaranteed. At present, it is used in the foundation pile construction of highways, railways, bridges and large buildings in China.

Telescopic drill pipe not only transmits rotating torque and axial pressure to the drill bit, but also uses its own flexibility to realize rapid lifting and unloading of the drill bit, thus shortening the auxiliary operation time of drilling and improving drilling efficiency.

Highlight the characteristics of environmental protection and clean the ground. This is because the rotary drilling rig takes soil by rotary drilling through the drill bit, and then lifts the drill bit away from the drilling hole by telescopic drill pipe of Kelly before unloading the soil. The mud used by rotary drilling rig is only used for wall protection, not for slag discharge. The mud used for hole formation is basically equal to the volume of the hole, and the mud can be reused many times after sedimentation and sand removal. At present, the construction sewage charges in many cities have increased significantly. Using rotary drilling rig can effectively reduce sewage charges and improve civilized construction level.

Crawler chassis is load-bearing and has low grounding pressure, which is suitable for various working conditions. The construction site is convenient for walking and shifting, the machine is flexible, and the positioning of pile holes is very accurate and convenient. (The old ones didn't have tracks yet, so they used sleepers. )

Rotary drilling rig has strong adaptability to strata, and can be applied to muddy soil, clay, sandy soil, pebble layer and other strata. An obvious spiral line is formed on the hole wall. It is helpful to improve the friction of piles. Hanging steel cages, pouring concrete and other construction sites are easier to arrange than other technologies. With diesel power, the contradiction of insufficient power in the construction site is alleviated, and the potential safety hazards brought by power cables are eliminated.

Scope of application Rotary drilling rig is generally suitable for clay, silt, sandy soil, muddy soil, artificial backfill soil and stratum containing some pebbles and gravels. Using the self-weight of drilling tools and the pressure of drilling rig, the rake teeth cut into the soil layer, and the drilling bucket rotates with different drilling tools under the action of rotating torque, which is suitable for dry (short spiral), wet (rotating bucket) and rock formation (coring drilling) hole-forming operations. According to different geological conditions, choose different drill pipes, drill bits and reasonable bucket tooth edge angles. For the drilling rig with high torque power head and automatic internal locking telescopic drill pipe, it can adapt to the construction of weathered rock stratum. At present, the rotary drilling rig has a maximum drilling diameter of 3m, a maximum drilling depth of 120m (mainly within 40m) and a maximum drilling torque of 620kNm.

The process principle is that the hole-forming process is different from other pile foundations. The drilling technology of rotary drilling rig adopts the technology of static mud protecting the wall and taking soil from the drill bucket (of course, there is also the technology of taking soil directly from dry soil, depending on the formation conditions on site), which is a drilling method without circulating flushing medium. However, in the process of drilling, in order to protect the stability of the hole wall, high-quality mud (stable liquid) should be used to fill the hole.

When the rotary drilling rig works, it can do integral rotary motion in situ. When the rotary drilling rig drills holes to borrow soil, it cuts into the soil layer by the self-weight of the drill pipe and the drill bit, and when the drill bucket rotates, the inclined bucket teeth cut off the clods and push them into the bucket to complete drilling and borrowing soil. When encountering hard soil, the dead weight is not enough to make the bucket teeth cut into the soil layer. At this time, the drill pipe can be pressurized by the pressurizing oil cylinder, and the bucket teeth can be forcibly cut into the soil to complete drilling and soil collection. After the drill bucket is filled with soil, the crane lifts the drill pipe and the drill bucket to the ground, pulls the switch on the drill bucket to open the bottom door, and the soil in the drill bucket is automatically discharged by its own weight. Put down the drill pipe and close the bucket door, then turn the hole to dig the next bucket. The rotary drilling rig is flexible. After drilling the last hole, it can move quickly or go to the next pile site for construction. The fabrication, hanging and post-grouting of reinforcing cage are the same as other pile foundation construction.

For more information about bid writing and improving the winning rate, click on the bottom customer service for free consultation.