ABSTRACT
The Heung Yuen Wai Highway, inaugurated on 26 May 2019, includes the 4.8 km Lung Shan Tunnel, the longest land-based road tunnel in the Hong Kong Special Administrative Region (HKSAR), China. A significant challenge was excavating large cross passages (CPs), particularly in soft ground conditions. These CPs, essential for emergency evacuation and housing E&M equipment, are typically excavated after the main tunnel’s lining is in place. To meet a fast-track construction schedule, the contractor, Dragages Hong Kong, opted to create the large CP openings before the main tunnel’s lining was constructed. This paper discusses the design and construction of these temporary support structures for large CP openings in a large-span mined tunnel. It includes numerical analyses to simulate stress redistribution around the tunnel’s support throughout the different stages of excavation. This paper offers a practical solution to challenges and aims to serve as a valuable reference for future tunnel construction requiring similar temporary support designs.
