Method to form in-situ pilings with diameters that can differ from axial station to axial station

A process for forming an in-situ piling which extends from and an intended top which is located at or near the surface of the soil to a depth, said piling having a central axis and a peripheral axially extending boundary extending from said intended top to its intended bottom, said piling comprising existing soil, existing water, and added dry binder, said process comprising:

• utilizing a driven rotary shaft having a central axis of rotation, driving a mixer-cutter blade adapted to cut into and stir said soil, said blade being adjustably attached to said shaft whereby to extend laterally from said shaft by an adjustable distance, thereby to cut a circular area equal to twice its adjusted distance, rotating said shaft and turning said blade into said soil, thereby to form a circular bore of loosened soil whose boundary is surrounding soil that is not cut by the blade;
• selecting and establishing along the axis of the bore at least two different said adjustable distances at axially spaced apart stations along said bore between the intended top and bottom of said piling, whereby to provide said boundary and thereby said piling with a plurality of axially spaced apart diameters;
• while continuing to rotate the shaft, removing said blades from said bore;
• at some time at every station between said intended top and bottom of said piling, injecting said dry binder into the bore and stirring of the mixture of said soil, dry binder and existing water;
• and
• permitting said mixture to cure to a hardened body of revolution comprising said in-situ pilings.