Sustainability of underground infrastructure – Part 2: Digitalisation-based integration and optimisation for low carbon design

Abstract

This paper integrates low-carbon strategies into conventional tunnel design practices, bridging the gap between traditional approaches and sustainable solutions. Geotechnical performance indicators and corresponding design parameters that influence embodied carbon are identified from preliminary considerations of support pressure in Convergence-confinement Methods (CCM) and detailed 3D numerical design of Tunnel Boring Machine (TBM) operation and machine-structure interaction. Low-carbon technologies in tunnelling in examples of worldwide projects are reviewed to provide benchmarks for industry practice. Using Building Information Modelling (BIM) as a centralised data platform that incorporates geomechanical properties and embodied carbon factors, multi-objective optimisation (MOO) is employed to balance decarbonisation and geo-structural performance of concrete lining, demonstrating significant carbon reduction potentials in Pareto optimal solutions. While strategies through adjustments to TBM operation and lining design can be further pursued in numerical simulation, the findings underscore the potential for realising low-carbon opportunities in tunnel design, particularly when ground conditions and other geo-structural factors are quantified early in the design process. The proposed workflow offers practical insights into the application of advanced design techniques, empowering engineers to make informed decisions that contribute to sustainable underground infrastructure development.