Published Paper Details:

Under logistical and environmental constraints, basement construction in dense urban settings requires excavation support systems that simultaneously control deformation, manage groundwater, and remain constructible. There are two types of retaining systems used for basement structures. A common framework for design criteria--especially near sensitive assets--includes cut-off effectiveness, resistance to base heave, and buildability considerations, as outlined by the study. Performance targets, construction logistics, project risks, and long-term durability are linked to the selection of system type through a qualitative decision-making model. To support early-stage design, the model is operationalized as a scoring matrix with sensitivity checks on soil stiffness, groundwater head, and reinforcement layout. Two scenarios illustrate typical deformation envelopes, risk pathways, and mitigation measures. The findings show that diaphragm walls offer advantages such as higher stiffness, better movement control, and watertightness. They can often serve as permanent basement walls, reducing structural demand and planning uncertainty. Regional unit cost rates, carbon factor (C-factor), and the need for project-specific validation of predicted movement are some of the limitations identified in the study. The research compares indicative costs and project scope normalized by excavation depth, and discusses how procurement strategy and quality assurance affect realized performance. The interplay between the embodied carbon of wall systems, energy efficiency, and waterproofing reliability is emphasized in the discussion. Gaps in the literature identified in the study encourage future work on performance databases. The model supports a transparent and defensible selection process for basement projects by linking early-phase option screening with construction-stage risk management.