Apparatus to form columns of granular material

Abstract

This invention, as a Continuation in Part of application Ser. No. 10/364,066, involves a drive syustem positioned at the base of an apparatus to install columns of granular material in soil. The present invention, with its rotary drive system positioned at the base of the apparatus, broadens the original invention by also utilizing a specially shaped cavity forming means to initially describe the cavity periphery and then form the cavity in a contiuous fashion, rather than the incremental fashion heretofore in use. Whereas the advance in the original involves advancing a hollow shaft element into soil at least in part by rotation, and adding equipment such as a storage and feed hoppers containing and feeding granular material to and through the hollow shaft element to fill the cavity in soil as the hollow shaft element is withdrawn to form a column, the present invention, with its rotary drive at the base of the apparatus can be used to produce the column in the same manner, but its novelty relates to being able to produce a cavity in soil by advancing the mandrel to its full depth with the rotary drive positioned at the base of the apparatus, as more fully described herein. While positioning the rotary drive on the support unit of the apparatus has been used, the position of the rotary drive has not been at the base of the support unit, and as the length of the element forming the cavity periphery in soil was limited to the distance between the rotary drive the ground surface, cavity formation heeded to be done incrementally and cavity support may have been required when soil is not self-supporting.

1 . Movable or mobile support apparatus to form a cavity in soil comprising a rotary drive means with a rotating hollow output shaft supported by said apparatus, said hollow output shaft is configured to mesh and coact with the external shape of a cavity forming shaft means in a manner to enable said cavity forming means to slide through said hollow output shaft as said cavity forming means advances into and through soil at least in part by rotation to define said cavity periphery, said cavity being formed as said cavity forming shaft means is withdrawn from said soil.  
     
     
         2 . The apparatus of  claim 1  applied to forming a column of granular material in soil by use of a conveyor means to supply said granular material from a storage hopper to a closable feed tank conjoined to a hollow cavity forming means with a movable cap at its forward end held in position by pressure from soil prevented from entering said hollow cavity forming means advancing into and through said soil to define said cavity, said feed tank is closed and pressurized with fluid as said hollow cavity forming means is withdrawn from said soil to form said cavity causing said cap to displace into said cavity as said granular material flows from said feed tank through said hollow cavity forming means into said cavity to form said column of said granular material in said soil.  
     
     
         3 . Apparatus of  claim 2  wherein said hollow cavity forming means has projections to move axially through said hollow output shaft as said projections which coact and mesh with said hollow output shaft to cause said hollow cavity forming means to rotate at least in part in advancing axially into and through said soil.  
     
     
         4 . Apparatus of  claim 2  with a feed hopper to hold a quantity of said granular material to supply said feed tank with said granular material to form at least one said column.  
     
     
         5 . Apparatus of  claim 1  wherein said cavity forming means is hollow and configured with at least one external projection to mesh and coact with said rotating hollow output shaft.  
     
     
         6 . Apparatus of  claim 4  where said projections orient axially along said hollow cavity forming means to define said cavity.  
     
     
         7 . Apparatus of  claim 4  wherein said projections orient in a helical manner around said hollow shaft to define said cavity.  
     
     
         8 . Apparatus of claims  5  wherein said rotary drive means conjoins said axial said projections in a manner to enable said drive to rotate said hollow cavity forming means and define said cavity periphery.  
     
     
         9 . Apparatus of claims  6  wherein said rotary drive means conjoins gaps in said projections in a manner to enable said drive to rotate said hollow cavity forming means and displace at least a portion of said soil upward to form said cavity as said hollow cavity forming means is withdrawn from said soil.  
     
     
         10 . Apparatus of  claim 2  wherein said conveyor means used to move said granular material from said storage hopper is positioned to discharge said granular material into a feed hopper configured to guide said granular material from said storage hopper into said feed tank.  
     
     
         11 . Apparatus of  claim 2  where movement of said granular material from said storage hopper to said tank is assisted by fluid pressure.  
     
     
         12 . Apparatus of  claim 2  wherein said granular material is made fluidic and able to be pumped by adding a foaming agent, and incorporating a pump means at an appropriate location to move said material as needed to and through the said hollow cavity forming means and into said cavity to form said column.  
     
     
         13 . The apparatus of  claim 11  wherein said granular material treated with a foaming is treated with a defoaming agent when its fluidic condition is no longer needed to form said column.  
     
     
         14 . The apparatus of  claim 2  wherein said granular material is predominantly sand and the column formed is a sand drain used to expedite consolidation of soft compressible soil.  
     
     
         15 . The apparatus of  claim 1  applied to form a column of wherein said granular material includes at least one additives to render said granular material fluidic so as to be conveyed by pumping from a storage hopper through a pipe or conduit to an inlet end of a hollow cavity forming means with a movable cap at its outlet end, with said cap held in position by the pressure of soil that is prevented from entering said hollow cavity forming means advancing into and through said soil axially and at least in part by rotation to define said cavity to the required depth, and withdrawal of said hollow cavity forming means to form said cavity causing said cap to displace into said cavity as said granular material flows through said hollow cavity forming means into said cavity to form said column.  
     
     
         16 . The apparatus of  claim 15  wherein said granular material is a mix which includes granular aggregate, cement and water to form fluidic concrete.  
     
     
         17 . The apparatus of  claim 15  wherein said granular material includes a foaming agent to render said granular material fluidic, and later adding a defoaming agent to undo the fluidic characteristic in the formed column.  
     
     
         18 . The apparatus of  claim 1  wherein said cavity is filled with suitable granular material to for a column in said soil.  
     
     
         19 . The apparatus of  claim 18  wherein said columns are contiguous to form a barrier in said soil.  
     
     
         20 . The apparatus of  claim 15  wherein said columns are contiguous to form a barrier in said soil.