岩石の回転穿孔性に関する研究 (第2報)

抄録

The present investigation is a continuation of previous study on the drilling performans and drillability of rocks by rotary drills.
In this research the following experimental formula have been newly determined.
T=Cp·√b·√t·l
T: the axial thrust necessary to get a certain penetration rate per revolution with two wingcd bit (kg).
b: mean value of bit wear in width measured at the center of each cutting edge (mm).
t: the penetration rate per revolution ranging from 0.065 to 0.47mm.
l: the total length of cutting edge (mm).
C_p, : constant depending upon rock property (kg/mm²)
As theC_pin this formula is seemed to be a useful index to diagnose rotary drilling resistance, it is compared with the mechanical, hardness properties of rocks. As the result it was found that the valueC_pis approximately proportional to the square root of the product of compressive strength, indentation hardness and shore hardness of rock.
The reason of this is explained in the last part of this paper.