Case Study:

Viking Link Temporary Wellpoint Dewatering

Client:

National Grid

Principal Contractor:

Balfour Beatty

Project Overview

Viking Link is a 1400 MM high voltage current electric link between the British transmission systems connecting at Bicker Fen and Jutland, Denmark.

The project originally involved the construction of a converter station in each country, with the installation of 760km submarine and underground cables, enabling electricity exchange between Great Britain and Denmark.

Accreditations Include:

- ISO 9001 (Cert. No. 11653)
- ISO 14001 (Cert. No. 11653)
- ISO 45001 (Cert. No. 11653)
- Constructionline, Gold.
- Achilles UVDB Silver +
- CHAS Accredited Contractor
- Builders Profile Safe Contractor

Before and After

Project Specifications

Construction of twin cable ducts and joint bays running through low lying fenland throughout Lincolnshire.

Joint bays would be constructed every 1000m and the cable would be pulled from joint bay to joint bay through the cable ducting and jointed.

National Grid insisted that the ground conditions were dry due to in-pipe ducting being laid on and surrounded by CBS (cement bound sand).

Being fenland meant the high water table together with only having a permit to pump 20,000 litres per day across the whole work site, would cause problems for the duct installation team and delay the program.

Groundwater control system

Solution

Alba Dewatering Services Ltd designed a dewatering system that would allow the ducting contractor to meet its program schedule, with the difficult site conditions.

The ground water control systems were designed to abstract the water and be used for recharge because of the low discharge pumping permits that the principal contractor had put in place, with the aid and advice of various environmental agencies.

Alba Dewatering installed the proposed system, the efficacy of which was then demonstrated to the environmental agencies for approval, which was achieved. Following this, we were asked if there was any way to increase production to allow a second duct laying crew, to get ahead of program.

A third installation crew and more equipment was deployed, to make the installation of the dewatering and drawdown of the water table more efficient.

Over the course of the project Alba Dewatering was totally self-sufficient, providing all machinery, fuels and welfare, completing six weeks ahead of schedule.