Geological input as applied to TBMs: A case study of the Kelinchi Transfer Tunnel, Malaysia

The Kelinchi Transfer Tunnel is the first tunnel in Malaysia bored by a Tunnel Boring Machine (TBM). Since the mechanical excavation technique is highly sensitive to geology, a comprehensive surface geological mapping was carried out to predict the probable ground conditions that would be encountered during the tunnel excavation. Unfavourable geological conditions that will be encountered, such as fault zones, shear zones, high water ingress, fractured and massive ground, were predicted with the help of satellite imagery, aerial photographs and field mapping, together with a limited number of exploratory borehole logs. Almost 75% of the ground conditions predicted from the above geological exploration methods were actually encountered during tunnel excavation. In addition, machine downtime, penetration rate and power consumption associated with the ground conditions are also analysed and presented.