Assessment of chalk rock mass in excavations

Chalk is widely distributed and well exposed in Israel. For thousands of years tunnels for various purposes have been excavated in this rock mass. This paper focuses on the applicability of the Q and RMR rock mass classification to chalk. From field measurements undertaken in seven different tunnels it has been concluded that the Q and RMR classification methods were too conservative. It is therefore suggested that a modification of the present classification methods, or a new classification, based on the chalk's strength is required.