Estimation of strength and stability of surrounding rock mass for Fuxi double-arch tunnel

The strength parameters of rock mass surrounding tunnel are the fundamental input indexes for the support design and stabilization calculation. Reliable determination of strength parameters of surrounding rock mass plays an important role in the design of tunnel support. In order to analyze the stability of rock mass for Fuxi double-arch tunnel, the uniaxial compressive strength of the rock mass is estimated using empirical equations proposed by Barton and Ramamuthy as well as Yudhbir separately based on the intact rock strength and Q-value of rock mss quality. The intact rock strength is determined from the point loading tests. It is seen that both the mean values and variances of strength predicted from Yudhbir’s relation are in good agreement with the values suggested by the code for design of road tunnel. It is shown that this method can provide a simple and effective way to evaluate the strength characteristics of rock mass quantitatively for future tunnel construction and design of tunnel support.