CD Core drill units

THE ROUND CONSTRUCTION PIT - The method of the future

There is increasing evidence that circular excavation pits are the conceptual solution for the trenchless installation and renewal of water, gas, power and data lines within the domain of property service connection techniques. In comparison to conventional square-cut excavation pits, the surface damage and consequential costs can almost be eliminated. The re-instatement surface work is performed in a much safer, more productive and cost effective way.

The core drill works a cylindrical core bore into the surface layer to cut open the excavation pit, with diameters of the opening ranging from 650 mm for minimally invasive keyholes to 1,500 mm for circular walk-in excavation pits. The bored out core is removed and set aside to be replaced later, it is then fitted back into the hole accurately with a special mortar when the work is done. This technique minimises stress fractures as there are no corners, so disruption is minimised and the road surface is re-instated sustainably.

One crucial benefit of round excavation pits, when compared to conventional square pits, is the long-term resistance of the repaired surface after the work has been carried out, this is due to the round shape. Re-sealed square excavation pits suffer strong term stress from the traffic running over or the thermal strain. The corners of square-cut pits are subject to stress peaks, so consequently severe cracks appear. If the excavation pit is circular, the strain is distributed evenly so stress is up to four times less.