How to Choose Drill Bits In Borehole Drilling Machine Construction?

Aug. 27, 2020

1. The main function of Advanced Crawler Mounted DTH Drilling Rig is to dig holes on the surface. Due to the different depths of the pile holes to be constructed, various terrain structures will be encountered during drilling. It can be roughly divided into the following categories:

(1) Clay: Use a rotary drilling bucket with a single bottom. If the diameter is small, use a two-part bucket or a bucket with a soil unloading plate.

(2) Silt, low-cohesive soil layer, sandy soil, and poorly cemented pebble layer with a small particle size can be equipped with a double-bottom drilling bucket.

(3) Hard clay: Use a rotary drilling bucket with a single inlet (single and double bottoms), or a bucket tooth straight screw.

(4) Frozen soil layer: Bucket-tooth straight spiral drill bucket and rotary drilling bucket with low ice content can be used, and cone spiral drill bit with high ice content can be used. It should be noted that spiral drill bits are used for soil layers (except (Except silt) are effective, but must be used in the absence of groundwater, so as not to produce suction and cause jamming.

(5) Cemented pebbles and strongly weathered rocks: need to be equipped with a conical spiral drill bit and a double-bottom rotary drilling bucket (single port for larger particle size, double port for smaller particle size)

(6) Stroke bedrock: Equipped with pick-barrel core bits-tapered spiral bits-double bottom rotary drilling buckets, or cut straight spiral bits-double bottom rotary drilling buckets.

(7) Micro-weathered bedrock: If the diameter of the rotary drilling bucket with cone-shaped spiral drill bit and double bottom is too large, the graded drilling process should be adopted.

Advanced Crawler Mounted DTH Drilling Rig

Advanced Crawler Mounted DTH Drilling Rig

2. In addition, the drill bit can also be selected according to the function of the rotary drilling rig.

If the small footprint Hydraulic DTH Drilling Rig has a continuous function, it can be equipped with a hydraulic grab or two-wheel milling for continuous construction. If the auxiliary winch has an automatic rope-laying function, you can choose percussion bits and grab bits to drill into large-diameter pebbles or boulders. If equipped with a gas chamber and a tap, gas-liquid drilling can be carried out. If it is equipped with a dual-power head or a pipe-rolling machine for casing drilling, this is an effective method for solving quicksand, broken pebble, and silt layers.

3. Choose drill bits according to other factors.

If the thickness of the ballast is relatively strict or the bottom drilling is carried out, a special ballast cleaning bucket is required. When drilling the pipe sleeve, the gap between the drill bit and the casing is small. In order to prevent the drill bit from hitting the casing and reduce the suction effect, the drill bit should be equipped with a ventilation hole, and the drill bit should be equipped with a guiding device and an opening and closing device Try to be as close as possible to the center of the drill bit, preferably one with the operator. This special problem can also be solved by choosing a combination of drill bits.