The air quality in the hole, the quality of the hole wall, the water gushing and quicksand and other geological conditions, the protection of the hole, the safety protection of the people in the hole and the operation of mechanical equipment probably all mean this. Do it one by one, and you'll be fine.

Rotary bored piles are divided into dry hole rotary bored piles and positive and negative circulation rotary bored piles.

When you say dry rotary drilling cast-in-place pile, you just use the crawler rotary drilling rig (there are many in Sany Heavy Industry) to directly drill down the hole to borrow soil, and there should be a loader next to it to push the dry soil away in time. This crawler rotary drilling rig is more suitable for friction piles in loess plateau area. The water level is low, and there is basically no rock layer in the pile-length stratum. Rotary drilling is fast, there is no water, the hole does not collapse, and there is no need for wall protection. But it is more troublesome to encounter water and rock layers.

Another rotary drilling rig is used to drill holes in areas with high water level or great plains. The soil quality is basically clay, silt, sandy soil, muddy soil, artificial backfill soil and stratum containing a small amount of pebbles and gravels. In this kind of digging, the soil is basically washed out by mud, and the drill bit will not be pulled out every time the soil is released. This kind of mud wall protection is needed, but it is very fragile. Whether drilling or emptying, we should keep the water head inside and outside the hole.