Victoria Cross Station cavern rock pillar stability.

Victoria Cross Station in North Sydney is one of the new stations on the Sydney Metro City & Southwest project constructed by the John Holland, CPB Contractors and Ghella joint venture as part of the Tunnel and Station Excavation (TSE) Works completed in 2021. The southern end of the station cavern is connected into the adjacent station shaft by twin adits. As a result of the geometrical design of this part of the station, a complicated junction is formed. A slender rock pillar, 4.4 m x 6.3 m x 6.0 m high, was formed by excavation of the 26 m wide station cavern, the connecting twin adits and adjacent shaft. The formation of the pillar together with the loss of lateral restraint for the cavern rock arch due to the shaft excavation resulted in a requirement to carefully consider the stability of the rock pillar. The author published a preceding paper presenting the excavation and primary support design of the station cavern (Shen 2021). This paper aims to elaborate on the challenges related to this particular rock pillar (termed the South Pillar) and presents the methods used to assess the stability and behaviour of the rock pillar, the results of the assessment and the performance of the pillar during construction. [ABSTRACT FROM AUTHOR]