Basic conditions for the main body of the rock drilling rig

The energy dissipation law and dynamic fracture criterion in rock clearly indicate: "When the loading energy is less than a certain threshold value, its loading energy does not participate in crack propagation at all, all of which is useless dissipative energy; when the loading energy reaches the dynamic fracture criterion, the rock Dynamic destruction, no power dissipation energy is about 15%." Based on this theory, the rock drilling rig must have large pressure capacity and large power head power (high torque and high speed).

First of all, rock rock can achieve the penetration and crack formation of rock joint under the action of large pressure. The cohesive force disappears and can be separated from the rock body only by overcoming the friction force. The small rock mass can be squeezed to freedom under the pressure. The crack propagates to the free surface, and the small rock mass is sheared off from the rock mass. It is also possible to form a complete rock with an RQD greater than 75 to form cuttings under rolling. Drilling can only be achieved if the complete rock is turned into pieces and debris.

Secondly, the high torque and high speed hydraulic power head is a necessary condition for impact work. On the bit cutting track of the drill bit, the pick impacts the raised rock mass, the power head is decelerated, and when the pick is over the raised rock mass, the speed is accelerated to the new protruding rock mass, and the rock is converted in high speed and low speed. The body is constantly being impacted. The greater the speed difference between high speed and low speed, the greater the impact of the protruding rock mass. Only the high torque and high speed hydraulic power head can increase the speed difference between high speed and low speed. For rotary drilling rig (power In the case of small rock-breaking machinery, the impact energy can effectively create some large loads to cross the [threshold value" of brittle fracture or plastic yielding of the rock. The rotary drilling rig must enter the rock to achieve the impact process.

From the perspective of rock drilling conditions, it is necessary to improve the vibration resistance of the equipment itself. The source of vibration in the rock entering operation is the interaction between the drill bit and the rock, the bending deformation of the drill pipe, the eccentricity of the drill bit, and the uneven distribution of the quality of the drill. The drilling pressure is continuously cycled in the boost, decompression, and floating modes. This cycle is controlled by the operator and has a frequency of approximately 0.10 to 0.3 Hz, which is one of the sources of rock into the rock. Secondly, in the rock operation, one or several drill teeth continuously hit the raised rock to form an irregular "brake" phenomenon. The higher the speed of the drill, the more uneven the rock, the higher the frequency of the "brake", and sometimes the vibration The frequency is high, and the vibration, excitation, and exhaustion regularity of the vibration is also poor. From the above sources of vibration, it is impossible to offset the damage caused by forced vibration by active vibration, and the vibration resistance of the equipment itself must be improved.

From the "threshold value" of brittle fracture or plastic yield of rock, it is required to apply sufficient force to the rock. This requires that the rock drilling rig must have sufficient weight to achieve the large pressurization capacity of the rig. In short, the large pressure, power head power and rig must have sufficient self-weight, which is the most basic requirement for the rock-in-drilling rig equipment itself.