Behaviour of Weak Shales in Underground Environments

Abstract

Predicting the ground response for tunnels in weak shales remains challenging. Predicting the ground response is challenged by difficulties in characterising the material, and our ability to predict deformations that are driven by coupled hydromechanical processes, when this material yields. The techniques that are used for characterising weak shales are reviewed, and three case histories are examined that demonstrate the behaviour of these weak rocks during tunnelling. A general framework is provided for assessing the squeezing potential for weak shales.