Abstract

This paper describes the application of rock behavior index (RBI) based on the rock engineering systems (RES) to assess the rock behavior around underground spaces. There are many geological parameters that affect the rock behavior around these structures. The most effective parameters taken into account in this paper are: uniaxial compressive strength, rock quality designation (RQD), joint surface condition, joint spacing, joint orientation, primary stress condition, ground water and tunnel span. The interrelations between the parameters and their effects on the whole system are determined by the expert semi qualitative technique (ESQ) and well-known analytical solutions in the literature. Interactive intensities were calculated and weights of the parameters were finally determined. Rock behavior was classified as stable, block falls, cave-in, buckling, rupturing, slabbing, rock burst, squeezing, plastic behavior and swelling clay by using an index. As a case study, Parsian tunnel located in the south of Iran was investigated by the proposed index. The tunnel route divided into four lithological units and were ranked using the Rock Behavior Index.

Key words: Rock behavior index, rock engineering system (RES), underground space.