Due to different construction techniques, most of the piles in hard rock stratum are small in diameter and mostly end-bearing piles, and most of them use impact drills, some of which use manual digging, and most of the small-diameter short-pile bridge piles use impact drills. Rotary drilling rig is mostly used to drill piles in sandy stratum, and it relies on high torque power head to drive screw bit to complete drilling work.

The cylinder is full of engine oil. The race of the thrust bearing divides the oil cavity into two parts, and the race is provided with oil holes. Due to the damping effect of oil flow, the impact vibration of the hook is absorbed during tripping operation, which can prevent the thread of the drill pipe joint from being damaged.

Rotary drilling rig relies on mud pump to form positive circulation or reverse circulation mud drilling. When the pile length is less than 40 meters in complex stratum, it is safest to use percussion drill. Geology, quality, or positive and negative circulation drilling rig are good, and the hole-forming quality is high, which can ensure the protective layer of steel dragon.

Extended data:

The lifting ring and the lifting ring seat are connected by a pin shaft, the lifting ring seat and the hook rod are welded into a whole, the cylinder and the hook body are connected by left-handed threads, and the threads are prevented from loosening by a stopper. The hook body and the cylinder can move up and down along the hook rod. The function of internal and external load springs is to make the column spring bounce when tripping out.

The upper end of the cylinder consists of six small springs and a locating plate. Through the friction between the positioning and the annular contact surface of the lifting ring seat, the lifting ring can be prevented from shifting due to rotation when lifting the empty elevator.

Baidu encyclopedia-positive and negative circulation drilling rig

Baidu encyclopedia-drilling rig