GROUND PROBING AND TREATMENTS IN ROCK TBM TUNNELTO OVERCOME LIMITING CONDITIONS

The negative consequences on TBM performances caused by an insufficiently complete and detailed “geo” characterization of the rock masses that have to be bored are discussed in the paper taking into account the possible ground probing operations in a TBM bored tunnel and the ground treatment techniques to be carried out ahead of the face that can be applied to make the construction of a bored tunnel feasible when limiting or prohibitive conditions for a TBM, must be faced. A description of some relevant and inspiring projects of TBM bored tunnels in rock where ground probing and treatments were used are also presented and discussed.tic approach and concept of physical volume of an inhomogenous medium. The numerical experiments on representative structures of rock masses have shown a good correspondence between the results obtained with the accurate and equivalent models