​Detailed Explanation of Two Rock Breaking Methods for Multi Functional Anchoring Drilling Rig

Detailed Explanation of Two Rock Breaking Methods for Multi Functional Anchoring Drilling Rig

The Multi Functional Anchoring Drilling Rig is one of the most common and critical equipment in engineering drilling operations. It employs only two rock breaking methods: one is rotary cutting, which is generally applied in rock formations with a hardness coefficient of f ≤ 8; the other is impact-rotary breaking, typically used in surrounding rock with a hardness coefficient of f ≥ 8.

Mechanism of Rotary Drilling Rig Rock Breaking

Rotary drilling rigs break rock by using multi-edge cutting bits to rotate and cut the rock, forming a circular borehole. Rotary cutting rock breaking requires the following conditions:

① The drilling rig must possess sufficient torque to overcome the resistance moment during bit cutting;

② The drilling rig must have a certain output speed to drive the rotation of the drill rod and bit;

③ A certain axial thrust must be applied to the drilling rig, i.e., a specific positive pressure on the bit, to achieve the feed motion of the bit cutting.

Mechanism of Impact-Rotary Drilling Rig Rock Breaking

The rock breaking mechanism of impact-rotary drilling rigs is as follows: under the action of impact stress waves, the drill bit cuts the local rock surface beneath its edges at a certain impact frequency. While performing impact motion, the bit also rotates, enabling it to break the rock within a 360° range in the borehole. Impact-rotary rock breaking requires the following conditions:

① The rock drill must possess a certain impact energy and impact frequency;

② The output shaft of the rock drill must achieve 360° rotation while performing linear impact motion;

③ A certain axial thrust must be applied to the rock drill.

From the rock breaking mechanisms, it is evident that the Multi Functional Anchoring Drilling Rig uses rotary rock breaking primarily for drilling anchor holes in roadways with soft roof conditions, such as coal seams or semi-coal rock seams (generally with rock stability coefficient f < 8). In contrast, impact-rotary rock breaking is used for drilling in rock roadways with harder roof conditions (generally with rock stability coefficient f ≥ 8).