In rock drilling, to obtain the ideal blasting effect, drilled holes should be drilled in the direction of the design requirements. If the actual position deviates from the design position during the construction, it will cause the drilling to deviate. The drilling deviation will not only fail to achieve the expected blasting effect but also cause the drilling to be scrapped and waste a lot of manpower and material resources. Therefore, we need to understand the causes of drilling deviation and prevent it.

Reasons for drilling deviation

1. The drilling positioning is not accurate.

2. When the drill spuds, the propulsion force is improper, resulting in hole opening errors.

3. Deviation in the drill hole during drilling.

The first two reasons can be avoided in principle by the operator’s skillful control of the rock drill. The third point is usually related to the geological conditions. For example, when drilling into a formation where the rock condition is composed of a layer of soft rock and a layer of hard rock, the drill bit will have a large drilling deviation if it is not drilled in the vertical direction of the rock face. The deviance degree depends on the angle between the drilling direction and the rock face. Too slow or slippery when drilling hard rock and too fast when drilling soft rock will cause large drilling deviations. Only when the operator estimates the boundary line between soft rock and hard rock according to the advancing speed of the drill rod and operating experience and takes appropriate measures can the occurrence of drilling deviation be reduced or avoided.

To achieve the expected blasting effect, it is necessary to make the drilled blast holes consistent with the pre-designed blast holes. This means that the position of the opening should be completely accurate, the direction of the drilling should be correct, and the depth of the drilling hole should match the depth of the drilling design. By measuring and calculating the position, depth, and quantity of the required drilling holes, drilling in strict accordance with the predetermined position and specified depth can obtain blast holes with high drilling accuracy. At the same time, the operating instruments and working conditions in the cab of the drill truck can also provide the operator with relevant drilling parameters and a good working perspective.

In summary, although drilling deviation is inevitable, we can reduce the deviation intensity by taking preventive measures such as reasonable hole layout, strict drilling rig installation, and careful operation. When the drilling deviates, the force can be applied in the opposite direction and measured multiple times to correct it in time and reduce the loss to the project.