Bored pile LARGE DIAMETER

concretesteelfoundation

The large diameter bored pile with temporary steel casing is a cast-in-place cylindrical concrete pile. The pile is a non-displacement pile, bored by means of a recoverable steel casing and - if necessary - water overpressure. Construction sequence Installation process in accordance with the requirements of NBN EN1536:1999 1. Positioning and drilling of the first section of the drill casing (recoverable steel casing as temporary support during the boring process) 2. While drilling, the drill casing – inside equipped with a drilling head fixed on a rod - is oscillated into the soil. (back and forth movement / twisting in place) 3. & 4. As the drilling process progresses, soil is removed from the borehole by the excavating tool (« bucket barrel » excavating the pile shaft) and additional sections of casing are jointed (added) to protect the soil from collapsing into the borehole during drilling. When drilling in non-cohesive soils below the groundwater level, a water overpressure (delta h) should be created in the temporary casing. 5. After reaching the design depth, clean-up of the borehole front, removal drilling tool, drilling fluid (water) pumped out from the bore. Formation of the pile : insertion and lowering of the reinforcement cage, pouring of the concrete. In the presence of water, concreting is carried out by means of a plunger tube to avoid segregation of the concrete (tremie pipe technique). 6. During the continuous concreting process, the temporary casing elements are progressively withdrawn whereby the concrete forms the pile shaft.