Estimation of Rock Mass Squeezing Potential in Tunnel Route (Case Study: Kerman Water Conveyance Tunnel)

One of the most important stages in the design and construction of underground spaces is the evaluation of ground conditions and the risks of tunneling, and in particular the squeezing potential of rock mass. Generally, tunneling is difficult and time-consuming under squeezing conditions. For this reason, it is very important to identify and estimate the squeezing conditions of rock mass in selecting a suitable excavation method and proper support system. In this study, the squeezing conditions of rock mass are investigated in the Kerman water conveyance tunnel. This tunnel transfers water from the Safa river dam to Kerman city for supply of drinking water. Firstly, geological zones, characteristics of rock mass, intact rock and classification of rock mass are presented and then, the estimation of the squeezing potential along Kerman water conveyance tunnel is investigated. Estimating of this phenomenon was done using empirical, semi-empirical, analytical theory approaches and a new probabilistic method called the Bayesian network. The results showed that the tunneling has a squeezing problem, especially in the ET-21 zone, which is due to the existence of the tectonic and faulted area along with weak rock properties.