The Application of GEO Publication No. 1/2023 to a Deep Excavation in Hong Kong

Abstract

This paper offers an overview of the implementation of the GEO Publication No. 1/2023 revamped monitoring scheme at an excavation and lateral support project (ELS) in Kwai Chung, New Territories. Introduced by the Geotechnical Engineering Office (GEO) in late 2023, this publication features significant differences from the monitoring practices commonly used across Hong Kong today, particularly regarding ground settlement. Adoption of design assumptions and guidelines from this publication in ELS submissions of the Project were made to the Buildings Department by the end of 2024 to replace the previous 3A monitoring with the new 5A trigger level, which received approval from government authorities as well as agreement from utilities companies. This paper will explore the distinctions between the new 5A levels and the traditionally used 3A levels outlined in the Practice Note for Authorized Person (PNAP) APP-137, while also considering the design water levels suggested and comparing with the common approach in Hong Kong. By examining these differences, the study aims to provide insights into the implications and benefits of adopting this newly released monitoring scheme for large-scale excavation and infrastructure projects in the region.