Laser Scanning to Reduce Over Digging and the Impacts of Unnecessary Truck Movements

At Marble Arch Place, Multiplex is digging a five storey basement, which will result in a large number of ‘muckaway’ trucks being required to remove the soil and clay required. Whilst laser scanning is now commonly used on sites, there are few companies that have used it extensively in basement digging.

Multiplex used this extremely precise technique to avoid removing any extra materials unnecessarily. As an example of potential impacts, an over-dig of 100mm of wet clay throughout the site would have resulted in 407m3 of material being removed (weighing about 743 tonnes), not to mention the additional material that would have required to bring the level back up to requirements. This is shown on a laser scan image of the site during the dig.

The avoidance of additional trucks to take away the material as well as more trucks to bring backfill materials (aggregates or concrete) has the benefit of reducing the following:

• Nuisance to the community from truck movements.
• Risk of collision by trucks with vulnerable road users.
• Extra pollution in an already heavily polluted central London location near Oxford Street.
• Additional greenhouse gas emissions.