Advancements in Design and Construction Practice for Deep Excavation

The building of basement or placing infrastructure underground has gained popularity in developed city, as it can maximise the development potential and optimise the planning of useable surface area. However, construction costs in Hong Kong could be prohibitively expensive and practitioners have to optimise the design to achieve a better return on the investment. In 1990, the Geotechnical Engineering Office (GEO) published GCO Publication No. 1/90 – Review of Design Methods for Excavation, which has since become the de-facto standard for design of excavation and lateral support (ELS) works. Over the years, significant advancements and novel solutions have emerged in the execution of ELS works. GEO has the undisputable role of shaping the geotechnical practice and certainly sees the need to partner with practitioners in producing practical and cost-effective solutions. Since 2021, GEO has worked with practitioners and regulatory authorities to prepare a new GEO Publication No. 1/2023 – Deep Excavation Design and Construction, which aims to provide guidance on ELS works with a right balance between safety and cost-effectiveness. Attempts were made to address the problems that had troubled many in the execution of excavation works for years. This paper discusses the rationale behind the technical advancements and improvements made in the new publication.