As the New Year approaches, Morgan Est will be anticipating the January delivery of its 3.6m diameter Lovat EPB machine for the 10km long Croydon Cable Tunnel project for the National Grid in Surrey, UK.
The tunnel is for the Beddington-Rowdown scheme that will see the tunnel being used as a conduit for power cables between two existing substations as a replacement for two 275kV cables that currently run underneath local roads and a major highway. The 10km tunnel will be lined with 1.2m long rings of six trapezoidal precast reinforced concrete segments produced by the contractor at their segment factory in Kent.
The EPB will be used to construct the 3m i.d. tunnel at depths varying from 8.3m to 83m from surface to the tunnel crown. The entire alignment is through local Upper Chalk with frequent occurrences of flint and mixed gravel. Lovat told T&TI an EPB pressure of up to 2.5bar was expected, although the TBM is designed for operation in EPB pressures of up to 8 bar.
The TBM is scheduled to be delivered to site in January and when driving it has a target advance of 3 no. rings per hour.
