Patent ID: 8821072

Claim:
A method for drilling the ground with excavation equipment for installation of foundation piles, said excavation equipment comprising: at least one drilling turret with a vertical guiding antenna; at least one rotary head for driving drilling batteries, the drilling batteries comprising at least one continuous ground drilling rotary propeller housed inside a covering tube; first inner drive means adapted for driving said propeller; second external drive means connected to the tube and allowing movement of the tube; the propeller and the tube being capable of rotating and moving axially relative to each other in a selective and independent manner; a driving cab for an operator, including: all manipulators for operating the excavation equipment, and systems for displaying and controlling measured parameters, sensors adapted to measure drilling parameters; said method comprising the following steps in sequence: excavating by drilling the ground and creating a borehole by extending the propeller and the tube to a predetermined depth; determining a preset depth at which the drilling operation carried out by the propeller ends, said preset depth being obtained by correlating said preset depth with a propeller excavation diameter and a predetermined volume of soil to be excavated; continuing excavation by rotating and advancing only the propeller with respect to the tube while holding the tube stationary; measuring said drilling parameters of said propeller and said tube; terminating the rotating and the advancing of the propeller when the propeller protrudes from the tube at the preset depth; determining total energy required by the drilling method, and determining actual specific energy of drilling as a function of energy required to overcome frictions associated with drilling into the ground by subtracting energy contributions of previously determined loadless measurements from the total energy to obtain information about consistency or density of the ground.