Which Rotary Drilling Rig Bits Should Be Used in Different Strata?

Rotary drilling rigs are the most common equipment in current pile construction. Since the geology of each place is different, how to choose the appropriate drill bit during the piling process has become a key issue. Today we will talk about how to After understanding the geological characteristics of the construction site, choose the rotary drilling rig drill bit.

Soil Bucket:

It is suitable for silt, fine sand, silt, silty clay, clay, and some types of soil soft rock, such as completely, strongly weathered and weathered mudstone, muddy sandstone, etc.; it is the most widely used drill bit in the industry.

Double Bottom Rock Bucket:

Suitable for egg and gravel layers, moderately weathered soil-like soft rock, such as weathered muddy sandstone, muddy conglomerate, etc. When drilling into hard rock with a high degree of weathering, such as completely and strongly weathered granite, it is often necessary to use a barrel drill and a spiral drill bit.

Core Barrel with Roller Bits :

It is suitable for circumferential cutting of moderately weathered sandstone with obvious layering (high probability of coring) and hard rock formations. In denser soil layers or some soft rock formations, when friction-type drill pipes cause slippage, you can try using a barrel drill.

Rock Auger:

It is suitable for crushing boulders, boulders, and hard rock formations in holes. For some clay strata and medium-densified pebble soil, when the double-bottomed sand bucket cannot be used to drill, you can try to use an auger bit to drill.

Double Core Barrel:

It is suitable for drilling into egg and boulder layers with a particle size of 200 to 500mm. The double-layer barrel drill adopts a new drilling idea of “squeezing”. That is, crushed pebbles of different sizes are squeezed in the cylinder and brought out of the hole. During design, the diameter of the outer cylinder is designed based on the diameter of the pile hole, and the diameter of the inner cylinder is designed based on the average particle size of the pebbles. The inner cylinder is taller than the outer cylinder. This drilling tool has been widely used in China, and its drilling efficiency and drill tooth loss are significantly better than other drilling tools.

Single bottom sand bucket:

This drill bit has similar functions to the double-bottom sand fishing drill bucket. The advantage is that it has a side soil inlet and does not need to back-drill to close the bucket door, so it can drill into the soil layer more efficiently. The disadvantage is that it is lightweight. When used in some hard soil layers, especially when used with friction rods, it may slip and fail to penetrate, seriously affecting drilling efficiency.

Soil auger :

It is only suitable for clay layers with small pile diameters and large cohesion. The advantage is that the maximum height of the drill bit can reach 4m, the amount of footage in a single time is large, and it can effectively avoid the problem of difficulty in unloading slag with other drill bits in such projects. It is recommended to use it within the applicable scope.

Double bottom single door drilling tools:

Generally, it is a drilling tool with a diameter of ≤1.2m. Compared with the double-bottom double-door drilling tool, it has a larger single-side soil inlet, which is more conducive to drilling in some formations, such as pebble formations with a particle size of less than 200mm. However, due to the asymmetric structure of the single door, there are higher requirements for design or production, otherwise, the phenomenon of partial holes will easily occur. This drill bit is recommended for drilling pebble formations with small pile diameters ≤1.2m.

Classification and uses of drill teeth:

Drilling teeth are components of the rotary drilling rig system that are in direct contact with the work object. Whether their selection, layout angle, layout spacing, and other parameters are correct has a decisive effect on construction efficiency. Good drill teeth should have the following characteristics: no cracks, continuous breaking, wear resistance, and easy disassembly and assembly.

1. Clay Teeth: suitable for soil drilling, with sharp tooth blades and fast cutting speed. They cannot be used in hard strata such as pebbles and rock formations.

2. Bauer teeth: Compared with bucket teeth, they are stronger and harder to break. They are used for large-diameter soil buckets and are suitable for small and medium-sized pebbles and soft rocks.

3. Bullet Teeth: drill teeth that penetrate the rock. The wear-resistant alloy points provide greater pressure to the rock and are suitable for rock crushing.

4. Roller Bits: Suitable for drilling super-hard rock, and crushing and breaking rocks. The rotation of the gear reduces the vibration when entering the rock. The multi-wear-resistant alloy knife extends the service life.

---

Thanks