Book Chapter or Section
This paper covers aspects of planning and designing of deep shafts with reference to two water distribution shafts under construction in New York City. The new shafts will be sunk into soil and rock to a depth to connect to existing Queens-Brooklyn tunnel section of City Tunnel No. 3 (CT3). The inside diameter of the upper parts of both shafts is 14.9 meter. Artificial ground freezing is specified as preferred method of excavation support for the entire stretch in soil. Excavation in competent rock will be performed using drill and blast technique preceded by a pre-excavation grouting program. Membrane waterproofing with sectioning is prescribed to limit groundwater infiltration to dry chambers.