Stirring apparatus for improving ground

A process for improving ground with a stirring apparatus having a rod body connected with the front end of an excavating rod, an upper stirring blade protruding from the outer surface of the rod body, a lower stirring blade protruding from the outer surface of the rod body and spaced from the upper stirring blade axially of the rod body, an upper discharge hole and a lower discharge hole that are formed in the outer surface of the rod body at the positions at which the upper and lower stirring blade protrude, respectively, for forcing the consolidating agent into the excavated hole through the rod body, and a casing held at a height between the upper and lower stirring blades and spaced from the outer surface of the rod body so as to be isolated from rotation of the rod body, said process comprising the steps of:

• rotating the excavating rod connected with the stirring apparatus;
• discharging a consolidating agent at least from the lower discharge hole in the rod body;
• stirring excavated soil and the consolidating agent with the upper and lower stirring blades;
• causing the excavation to proceed while shaping the mixture of the excavated soil and the consolidating agent stirred with the lower stirring blade into the cross section of the casing which drops after the stirring;
• discharging the consolidating agent at least from the upper discharge hole after the excavating rod reaches a desired depth;
• stirring the mixture of the soil and the agent again with the upper and lower stirring blades;
• and
• withdrawing the excavating rod while shaping the mixture stirred with the upper stirring blade into a boxlike form by the casing that is elevated after the stirring, thus creating a consolidated body of a rectangular cross section.

Apparatus for forming hardened shafts of earth to provide foundations for building structures comprising:

• a rotatable tubular earth auger having a longitudinal axis;
• means to vertically position and to rotate said tubular earth auger about said longitudinal axis;
• an upper earth-stirring blade sleeve slidably fitted about said rotatable tubular earth auger to freely shift along said longitudinal axis;
• an upper earth-stirring blade secured to and projecting laterally from said upper earth-stirring blade sleeve;
• a lower earth-stirring blade sleeve slidably fitted about said rotatable tubular earth auger to freely shift along said longitudinal axis;
• a lower earth-stirring blade secured to and projecting laterally from said lower earth-stirring blade sleeve, said upper and lower stirring blade sleeves being integrally secured together and vertically spaced apart along said longitudinal axis;
• an upper hardening agent discharge hole in said tubular earth auger adjacent said upper stirring blade sleeve;
• an upper hardening agent discharge hole in said upper earth-stirring blade sleeve in longitudinal axial alignment with said upper hardening agent discharge hole in said tubular earth auger;
• a lower hardening agent discharge hole in said tubular earth auger adjacent said lower stirring blade sleeve;
• a lower hardening agent discharge hole in said lower earth-stirring blade sleeve in longitudinal axial alignment with said lower hardening agent discharge hole in said tubular earth auger;
• said upper discharge hole in said upper sleeve being concentrically alignable with said upper discharge hole in said tubular earth auger by shifting said sleeves, said lower discharge hole in said lower sleeve being concentrically alignable with said lower discharge hole in said tubular earth auger by shifting said sleeves, said upper and lower discharge holes being so spaced apart that when said upper discharge holes are in concentric alignment said lower discharge holes are non-aligned, and when said lower discharge holes are in concentric alignment said upper discharge holes are non-aligned;
• means to prevent rotation of said sleeves about said tubular earth auger and to delimit shifting of said sleeves upwardly to concentrically align said upper discharge holes and to simultaneously non-align said lower discharge holes, and to delimit shifting of said sleeves downwardly to concentrically align said lower discharge holes and to simultaneously non-align said upper discharge holes, wherein said sleeves shift upwardly when said auger penetrates the earth and shift downwardly when said earth auger is withdrawn from the earth;
• a support sleeve slidably fitted about said tubular earth auger to provide free relative rotation between said tubular earth auger and said support sleeve;
• detent means on said tubular earth auger to prevent vertical shifting of said support sleeve on said tubular earth auger;
• an open-minded rectangular four-sided casing supported on said support sleeve wherein said earth auger is free to rotatably penetrate the earth while said open-ended rectangular four-sided casing is prevented from rotating with said earth auger by frictional and pressure contact between said open-ended rectangular four-sided casing and the earth;
• and an auger bit secured to the lower end of said tubular earth auger adapted to penetrate the earth when said tubular earth auger is rotated.