ABSTRACT
This paper describes the observational approach used to plan, design, construct, and monitor for an atmospheric cavern 30m below water level on the project Trunk Road T2 in Hong Kong. The project involved a 3.4km dual two-lane trunk road with 2.4km of subsea tunnels and two ventilation buildings. A ground investigation campaign and risk assessment were conducted during feasibility assessment and the design process. Rock fissure grouting works were carried out using an observational approach to maximize performance, with a validation process for safety assurance. Results show the effectiveness of the fissure grouting works and monitoring of ground conditions to maintain and control atmospheric pressure. This uncommon grouting operation presents a unique case study, highlighting challenges and solutions implemented to ensure project success.
