The construction of the long auger rig should select the drill bit according to the geological conditions of the site:
(1) Stroke bedrock: Equipped with a pick barrel-type coring bit -- a conical auger bit -- a double-bottom rotary drilling bucket, or a straight auger bit with a pick -- a double-bottom rotary drilling bucket .
(2) For silt, weak cohesive soil layer, sandy soil, and pebble layer with poor cementation and small particle size, a double-bottom drilling bucket can be used. (3) Hard cement: choose a rotary drill bucket with a single soil inlet (single and double bottoms), or a bucket tooth straight screw.
(4) Clay: use a single-layer bottom rotary drilling bucket, if the diameter is too small, a two-lobed bucket or a drilling bucket with a soil discharge plate can be used.
(5) Cemented pebble gravel and strongly weathered rock: need to be equipped with a conical auger bit and a double-bottomed rotary drilling bucket (single-port for larger particle size and double-port for small particle size)
(6) Micro-weathered bedrock: Equipped with roller cone-type coring bit - conical auger bit - double-bottom rotary drilling bucket, if the diameter is too large, a graded drilling process should be adopted.
(7) Frozen soil layer: straight auger buckets and rotary drilling buckets with small ice content can be used, and conical auger bits can be used with large ice content. It should be noted that the drill bit is used for soil layers (except for Sludge and silt) are all effective, but they must be used without groundwater, so as to avoid suction and cause stuck.
General soil layer auger bit: mainly suitable for non-circulating drilling in soil layer, sand layer, dense sand layer containing a small amount of clay, and sandstone layer with small particle size. Wear-resistant alloy bucket teeth plus picks, the structure is straight spiral, and it is divided into three types: single-head single-screw, double-head single-screw, and double-headed double-screw. The single screw bit is suitable for drilling in pebble layers and clay layers with good cementation due to its easy slag cleaning and low turning resistance.
Special auger bit for rock: It is mainly suitable for non-circulating drilling in weathered bedrock, cobblestone formation with good cementation and permafrost layer of various drawings. The alloy picks imported from the United States have the structure of straight screw and conical screw. According to the stratum and the soil rejection performance of the drill bit, they can be divided into single-head single screw, double-head single screw, and double-head double screw.
During the construction process, the CFG drilling rig should pay attention to the reasonable use of the auger bit, daily maintenance, and the drill bit should be replaced in time after a certain period.
