LAUSR

Hazard warning levels criterion based on the critical strain concepts, which have been issued by Sakurai, is widely used in the stability assessment of tunnels. Many studies have been performed concerning the effect of the water content on the strength and deformability of rocks, but the effect of water content on the strain as the basis of some stability criteria has hardly ever been investigated. This study aims to render an account of the effect of the water content on the critical and failure strains in more details making use of uniaxial compression strength test results pertaining to 67 samples of eight rock types under dry, natural and saturated conditions. The results depicted that variations of the critical and failure strains have mainly occurred in water contents less than 2%. Variations of critical and failure strains in the mentioned value have mostly increasing and decreasing trends respectively. In view of the fact that the variations are not so considerable, the effect of the water content on them can be neglected.