Patent ID: 8757935

Claim:
A jet-grouting equipment for forming consolidated soil columns having a non-circular cross-section, comprising: a mast; a rotary, translatable along an axis parallel to the mast and controllable upon rotating around said axis, and sliding along the mast; a string of cylindrical hollow rods passing through the rotary and overhung from the rotary, the string having an overall length greater than a rotary stroke along the mast, said string being temporarily unlockable from the rotary by a mast clamp mounted at the mast base; supplying means for injecting a consolidating fluid grout into the soil through the string of hollow rods; a rotor directly secured to one of the rods of the string, the rotor being operatively coupled to at least one signal generating device, said signal generating device is mounted to a non-rotating part of a trolley of the jet-grouting equipment and is adapted to generate an electric signal indicative of an instantaneous angular position of the rotor; means for varying rotational speed of the rotary in at least one predetermined angular range around said axis, using said electric signal as a control signal for varying the rotational speed of the rotary as a response to the instantaneous angular position of the rotor; and a through clamp, mounted to a rotatable mandrel of the rotary, provided with locking means which can be activated to clamp a rod and make the rod integral to the rotary, and which can be deactivated to release the rod to allow the rotary to move relative to the rod.