Hybrid Monte Carlo simulation and ANFIS-subtractive clustering method for reliability analysis of the excavation damaged zone in underground spaces

Excavation of an underground construction by drilling and blasting creates a zone of damaged rock around underground spaces. This zone affects the behavior of mass rock surrounding the underground spaces, which reduces the stability and increase probability of failure of the structure. In this paper a methodology was examined for computing the creation probability of damaged zone by hybriding Monte Carlo simulation (MCS) and Adaptive neuro-fuzzy inference system-subtractive clustering method (ANFIS-SCM). Also, estimating of the extension of damaged zone was addressed. A case study in a test gallery of the Gotvand dam, Iran was carried out and creation probabilities of 0.12 for highly damaged zone (HDZ) and 0.32 for EDZ were achieved. Based upon the experts' views, these values mean that almost the level of damage to the rock mass is low. Also, an extension of approximately 0.5-1 m for excavation damaged zone was obtained.