Demolition of Abandoned Basement in Congested Urban Area

This paper presents two cases of basement demolition in built-up urban area. Micropiles in conjunction with proper groundwater drawdown using well points are adopted in the first case as temporary retaining during the period of basement demolition and removal. Watertight sheet piles with internal bracing struts are used in the second case to resist earth pressure and groundwater pressure. During the entire course of construction, both cases were successfully executed without disturbing adjacent ground and damaging buildings at a close proximity. This paper emphasizes that a sufficient knowledge on ground behavior and a good sense on construction details are prerequisites for such complicated excavation projects.