Shigen-to-sozai, Vol.118, No.3,4, pp.171-178.
Erosion Strength of Crystalline Rocks and the Effect of Rock Stresses
Katsuhiko SUGAWARAa, Takashi TAKEHARAb Akira SATOc and Takayuki HAMAURAd
| a. Graduate School of Science and Technology,
Kumamoto University, Kurokami, Kumamoto 860-8555,
Japan b. National Institute of AIST c. Faculty of Engineering. Kumamoto University d. Tokyu Construction Co., Ltd. |
| Characteristics of the erosion strength of crystalline rocks is presented and discussed, which is of fundamental Importance for determining the pure water jet drilling performance. A formulation of the erosion strength is presented from the dimensional. analysis of a rectangular particle separation from bottom surface, assuming the anisotropy of the microscopic tensile strength of rocks, and the effect of rock stresses originally acting perpendicular to the drilling axis is discussed in consideration of the stress concentration at the bottom surface. The validity of the present formulation is successfully clarified by analyzing the pure water jet drilling experiment of marble and granite under a biaxial compression, together with the effect of the anisotropy of the tensile strength. As concerns to the chipping upon water jet drilling, it is shown that the incidence of chipping upon drilling, increases with increasing of the confining pressure. |
| KEY WORDS: Water Jet, Erosion, Erosion Strength, Chipping, Rock |