C902

Mass Transit Railway Corporation Limited

Nishimatsu Construction Co. Limited

Tunnel metro alignment formed by drill and blast excavation for approximately 3.5 kilometres running, between Admiralty Station to the north and the Nam Fung Ventilation Building to the south, beneath Hong Kong Island. The terrain rises above the alignment to a maximum level of +325 metres Principal Datum (mPD), about 310m vertically, at Mount Cameron above the alignment. 

I&M for the completed works and Existing Buildings and Structures (EBS) potentially affected by the site activities. The installations ranged from Building and Ground Settlement Markers (BSM and GSM), approximately 6No. inclinometers and Extensometers and about 10No. standpipe and piezometer installations. The monitoring was concentrated towards the Nam Fung portal, which required Excavation and Lateral Support (ELS) extending to 40m depth, and the HK Part Ventilation Shaft, which had a 20m diameter shaft extending to 50m depth. A major challenge was the high degree of groundwater fluctuation, which was monitored by Vibrating Wire Piezometer installation with records taken in real-time. Factual I&M reports and presentation of data using Lam’s in-house software was prepared for use in Detailed Action Plans prepared by the main contractor. 

2015