Plunged columns for top down construction

We developed the Cemloc© system to accurately place plunged columns into diaphragm walls and bearing piles. This system is particularly effective when carrying out ‘top-down’ construction, allowing upward construction work to be carried out simultaneously with excavation of the basement, and resulting in significant time saving.

Bearing piles and diaphragm walls

The bored pile retaining wall is installed from existing ground level. The main bearing piles are also installed with very accurately placed structural steel columns cast into them as part of the piling process.

The ground floor slab is cast, leaving a hole in the centre, and the basement excavated from underneath. The spoil is removed via the hole. The piles are already in place, as are the structural columns. Construction can therefore carry on upwards as well as down, without waiting for the basement to be finished.

Time saving technique

We used this method while working on the basements at Harrods in Knightsbridge, saving the client 15 weeks of construction time. As well as cutting construction time, the use of Cemloc© means there is no need for:

  • permanent liners
  • personnel to descend to trim back the pile head
  • pile caps or base plates
Last updated: 23/01/2017