Tools and methods for constructing large diameter underground piles

摘要

Methods are provided for the creation of large diameter piles in all types of soils (cohesive, cohesionless or rocky), particularly for the construction of bulkheads made of juxtaposed or secant piles, while maintaining the deviation from the vertical well below the limit ≦2% required by European standard EN 1536. The invention reduces verticality errors, advantageously exploiting the accuracy provided by the directional drilling technology. Tools for implementing such methods are also provided.

主权项

1. A method of constructing large diameter underground piles, comprising the steps of:
a) providing an underground, small diameter cylindrical pilot core made of mechanically erodible material extending along a central axis of a pile to be constructed; b) excavating the soil around the pilot core using the pilot core as a guide for a drilling tool, the tool comprising: a central, cylindrical guiding cavity adapted to fit around the core; first lower cutter elements for drilling the soil underneath the tool; and second inner cutter elements located above the cylindrical guiding cavity, for milling the top of the core as the tool moves downward guided along the same core; and c) milling the top of the core as the tool moves downward guided along the core and filling the borehole formed by the soil excavation with concrete.