An Improved Method for Estimating the Strength of Jointed Rock Mass Using Drilling Technology

Figure 3

The distributions of fracture, specific energy, and standard deviation in each length range. (a) The core log, drilling energy, and standard deviation of drilling energy from the depths of 0 to 0.4 m in marble. Drilling energy and standard deviation correspond to a single fracture in marble was observed at the depth of 0.265~0.283 m. (b) The core log, drilling energy, and standard deviation of drilling energy from the depths of 0 to 1 m in limestone. Drilling energy and standard deviation correspond to fracture zones in limestone were observed at the depth of 0.0.185~0.831 m.

(a)

(b)