How do we calculate the length of a drill for a bored pile drill?
Pile system refers to the construction site by mechanical drilling steel soil compaction or human mining method in the foundation pile hole in form, and placed in the steel cage, pouring concrete piles and made, in accordance with the different drilling method, grouting pile can be divided into cast-in-place pile, bored pile and digging pile and other types of. Bored pile is a kind of pile type defined according to the method of pile formation.
There are two main types of drilling rigs: rotary drilling machine and impact drilling machine. The bit of rotary drill is divided into three kinds of scraper drill: suitable for quicksand and silt layer. Only the diameter and weight limit, no length limit cone drill: suitable for soft stone and hard soil. There is no length limited hob drill: suitable for hard rock layers. There are weight limit and hob arrangement, hardness requirements above, there is no drill length requirements. Impact drill: it is to use the weight of the drill to squeeze the soil into the hole, and the hole of the rock is also to use the bit itself to destroy the rock structure surface into holes. Only the weight on bit (according to the requirements of classification of rock hardness determine bit weight, diameter of 2-2.5 meters in the drill hole, the weight of at least 10 tons; 1.5-2 meters, bit weight of about 5 tons, 1.5 meters below 3 tons. For impact drilling, the length of the drill has a certain requirement, usually 1.8-2.5 meters high. Because the longer the drill bit, the stronger the impact drilling guidance function, the smaller the possibility of partial hole, hammer and hammer, the higher the standard of drilling. There are no rules and regulations, and you can succeed by experience.
The length of the drill bit is reduced by 2/3, or 1/3 of the drill bit.
