SCIPRESS FORMA
Forma, Vol. 9 (No. 2), pp. 113-123, 1994
Original Paper

Characterization of Jointed Rock with Fractal Dimension

Tadayuki Shirono

Structures Section, Givil Engineering Research Institute, Hokkaido Development Bureau, Hiragishi 1-3, Toyohira-ku, Sapporo 062, Japan

(Received October 19, 1993; Accepted December 10. 1993)

Keywords: Characterization, Jointed Rock, Fractal Dimension, Box Counting, Resolution

Abstract. A good documentation of cutting faces and crowns in tunnel boring is important. However, it is difficult to characterize the appearance of rock fractures due to its complexity. This investigation proposes to use fractal dimension as a synthetic index to describe the roughness, frequency, and distribution of jointed rock fractures in real tunnels. The results show the fractal dimension 1.02-1.22 in faults or conspicuous macrofractures (hereafter called superfractures), 1.07-1.26 in macrofractures, and 1.20-1.28 in both of the fractures. The results also show that the fractal dimension of superfractures has a mutual relation with the final crown settlement before the secondary lining of the tunnel.