Integration of 3D geological model and architectural model for design and construction of bored tunnel in Singapore

This study focuses on the development of a three-dimensional (3D) geological model based on the exploratory borehole data and its integration with architectural model of the Riviera Interchange Station and Tunnels for the Cross Island Line Punggol Extension of Mass Rapid Transit (MRT) in Singapore. The integrated model was used during the design and construction planning stages to support decisions related to excavation volume estimation and tunnelling strategy. One key achievement is the ability to calculate the anticipated excavation volume by geology for each 1.5 to 2-metre ring of tunnel lining, which assisted in aligning excavation methods with ground conditions. However, challenges remain, particularly in addressing uncertainties inherent to 3D geological modelling. Due to the linear nature of tunnels, borehole investigations are typically aligned longitudinally, resulting in limited cross-sectional data and more uncertainty in geological predictions perpendicular to the tunnel alignment. Future refinements may help improve the reliability of geological modelling and its application in tunnel construction planning.