Method and Apparatus for Casting a Concrete Pile in the Ground

Abstract

A concrete pile is cast in the ground by driving a plate into the earth with a tubular mandrel to create a shaft. Fluid grout injected into the mandrel can flow from the mandrel to fill the shaft. The plate is tethered to the mandrel and is recoverable for reuse when the mandrel is withdrawn from the grout filled shaft.

1 . An apparatus for creating a shaft in earth, said apparatus comprising:
 (a) a plate;   (b) an elongate tubular mandrel having an end bearably engageable with a first surface of said plate, said mandrel arranged to urge said plate into the earth; and   (c) a tether attached proximate a periphery of said first surface of said plate and affixed to said mandrel proximate a central longitudinal axis of said mandrel and arranged to support said plate with said first surface and a spaced apart second surface aligned approximately parallel to and spaced approximately equal distances from said longitudinal axis of said mandrel when lifted by said mandrel.   
     
     
         2 . (canceled) 
     
     
         3 . The apparatus of  claim 1  wherein said tether comprises a flexible member. 
     
     
         4 . The apparatus of  claim 1  wherein said tether comprises a chain. 
     
     
         5 . The apparatus of  claim 1  further comprising a pin secured to said mandrel and arranged substantially normal to said longitudinal axis of said mandrel, said tether secured to said pin. 
     
     
         6 . The apparatus of  claim 1  wherein said plate further comprises an aligning feature slidably engageable with said mandrel and operable to align said plate in directions normal to said longitudinal axis of said mandrel. 
     
     
         7 . The apparatus of  claim 6  wherein said centering feature comprises plural pins affixed to said first surface of said plate and arranged for slidable engagement with an interior surface of said tubular mandrel when said end of said mandrel is bearably engaged with said plate. 
     
     
         8 . A method of creating an earthen shaft for a concrete pile comprising the steps of:
 (a) driving a plate into earth with an elongate tubular mandrel, said plate tethered to said mandrel by a tether having a first end connected to said mandrel proximate a longitudinal centerline of said mandrel and a second end connected proximate a periphery of a surface of said plate; and   (b) withdrawing said mandrel and said plate from the resulting shaft.   
     
     
         9 - 10 . (canceled) 
     
     
         11 . A method for creating a concrete pile in the earth comprising the steps of:
 (a) placing a plate on an earthen surface;   (b) engaging a first surface of said plate with an end of an elongate tubular mandrel, said plate attached to said mandrel by a tether affixed proximate a longitudinal axis of said mandrel and at a periphery of said first surface of said plate;   (c) driving said mandrel and said plate into the earth to create a shaft;   (d) injecting a fluid grout into said tubular mandrel while driving said plate, said grout flowable into said shaft from said mandrel at a portion of a wall of said mandrel defining a grout passage proximate said end of said mandrel; and   (e) withdrawing said mandrel and said plate from said shaft, grout in said mandrel flowing from said end of said mandrel as said mandrel is withdrawn.   
     
     
         12 . The method for creating a concrete pile of  claim 11  further comprising the step of blocking said grout passage in said mandrel during withdrawal of said mandrel and said plate. 
     
     
         13 - 14 . (canceled)