During a Tunnel Boring Machine (TBM) project in Kunming city, Southwestern China the engineering geological conditions encountered at a distance of 7km consisted of folded, faulted, weak rocks, high ground stress and groundwater problems. The problems of collapse, squeezing, debris flow, water loss from reservoir and accidents resulting from the TBM jamming were encountered. As a result a lot of measures, e.g. chemical reinforcement, adit excavation and advanced test jack hammer excavation outside of shields were adopted to cope with these difficult ground conditions. An adjustment to the tunnel line had to occur after 4km of boring in these difficult ground conditions. This paper presents lessons learnt from this case study. In particular increased costs and time delay due to the transfer of water from a reservoir to Kunming city are

reported. Decisions made on what excavation method (blast and cast or a TBM) are strategic decisions that define the success and progress of a tunnelling project. The difference of the deformation and failure mechanism that occur to the surrounding rocks under a TBM tunnelling method from that under blast and cast method should be clarified when undertaking a project of this nature.