Novel system and method for installing grout-filled friction piles

Abstract

The friction pile system may include a steel pipe column, an auger spiraled around its exterior surface, a helical plate near the tip, and small structural elements located around the helix. A plurality of perforations may be provided on the pipe wall. The method of installation includes screwing the pipe assembly down into the ground by rotating it with a drivehead and simultaneously pressure injecting cement grout inside the pipe. The structural elements including weld beads maintain the bore hole created by the rotating helix and also guide grout to flow out though the perforations and upward along the auger while spreading outward filling in the hole. Thus the engineered pipe assembly leverages the mechanical energy of drilling to pressurize grout upward and outward improving bond with soil yielding high pile capacity.

What is claimed is: 
     
         1 . A novel grout-filled friction pile system, comprising:
 a hollow column having an interior comprising a centrally disposed longitudinal axis extending in a longitudinal direction from a driving end to a closed end, the column having an outside surface, an inside surface, and a first width extending in a lateral direction perpendicular to the longitudinal direction;   an auger portion disposed on the outside surface of the column and comprising a first helical pattern fanning out in the lateral direction, the auger portion extending in the longitudinal direction along the outside surface of the column towards the top end; and   a plurality of perforations selectively disposed along the column and penetrating the outside surface and inside surface, the plurality of perforations configured to provide a passageway for supplying cementitious material from the interior of the column through the outside surface as excreted cementitious material,   wherein the auger portion is configured to convey the excreted cementitious material towards the top end upon rotation of the column around the longitudinal axis.   
     
     
         2 . The friction pile system of  claim 1 , further comprising a capping portion disposed at a tip of the driving end and including a surface that substantially closes the driving end. 
     
     
         3 . The friction pile system of  claim 2 , comprising:
 a helix portion disposed on the outside surface of the column proximate the driving end and comprising a second helical pattern configured to drill the column downward into the ground upon rotation of the column around the longitudinal axis, and   wherein the auger portion is disposed at an elevation that is above the helix portion.   
     
     
         4 . The friction pile system of  claim 3 , wherein an outside edge of the helix portion extends a first distance from the outside surface of the column in the lateral direction and an outside edge of the auger portion extends a second distance from the outside surface of the column in the lateral direction, the first distance being greater than the second distance. 
     
     
         5 . The friction pile system of  claim 3 , wherein the auger portion comprises a first pitch and the helical portion comprises a second pitch, the first pitch being greater than the second pitch. 
     
     
         6 . The friction pile system of  claim 5 , wherein the first pitch is about twice that of the second pitch. 
     
     
         7 . The friction pile system of  claim 1 , further comprising a plurality of structural elements disposed on the outside surface of the column,
 wherein at least one structural element of the plurality of structural elements is disposed proximate a corresponding perforation of the plurality of perforations, and   wherein at least one structural element of the plurality of structural elements is configured to push the excreted cementitious material away from the outside surface of the column during rotation of the column.   
     
     
         8 . The friction pile system of  claim 1 , further comprising a plurality of structural elements disposed on the outside surface of the column, at least one structural element of the plurality of structural elements is disposed proximate a corresponding perforation of the plurality of perforations and configured to protect the perforation during rotation of the column. 
     
     
         9 . The friction pile system of  claim 8 , further comprising:
 a helix portion disposed on the outside surface of the column proximate the driving end and comprising a second helical pattern configured to drill the column downward into the ground upon rotation of the column around the longitudinal axis, and   wherein the plurality of perforations includes a first perforation disposed proximate the helix portion.   
     
     
         10 . The friction pile system of  claim 9 , wherein the first perforation comprises a reinforced weep hole. 
     
     
         11 . The friction pile system of  claim 1 , wherein the interior of the column is configured to be substantially filled with the cementitious material. 
     
     
         12 . The friction pile system of  claim 11 , wherein the outside of the column is configured to be substantially surrounded by the conveyed excreted cementitious material. 
     
     
         13 . The friction pile system of  claim 1 , further comprising a plurality of reinforcement angles disposed on the outside surface, each reinforcement angle of the plurality of reinforcement angles extending in the longitudinal direction between a corresponding top surface of the helix pattern to a corresponding bottom surface of the auger pattern. 
     
     
         14 . The friction pile system of  claim 13 , wherein each reinforcement angle of the plurality of reinforcement angles extends laterally from the outside surface in the lateral direction. 
     
     
         15 . A method for installing a friction pile system, comprising:
 providing a pipe assembly system, comprising:   a hollow column extending in a longitudinal direction and having a substantially closed end, the column defining a centrally disposed longitudinal axis extending in the longitudinal direction, the column including an outside surface and an inside surface,   a helix portion and an auger portion extending along the outside surface of the column from a lower elevation of the column to an upper elevation of the column, and   a plurality of perforations, the plurality of perforations including a first perforation disposed proximate the lower elevation of the column and penetrating the outside surface and inside surface of the column,   injecting cementitious material under pressure into an interior of the column through an upper end of the hollow column;   excreting the cementitious material from the interior of the column through the first perforation;   rotating the pipe assembly system; and   conveying the excreted cementitious material along the auger portion from the lower elevation to the upper elevation.   
     
     
         16 . The method of  claim 15 , wherein: the friction pile system further comprises a plurality of V-shaped gussets disposed on the outside surface of the column and extending laterally from the outside surface of the column, each V-shaped gusset being disposed proximate an elevation of a corresponding perforation of the plurality of perforations. 
     
     
         17 . The method of  claim 16 , further comprising:
 pushing the excreted cementitious material away from the outside surface of the column via the plurality of v-shaped gussets, and   wherein at least a portion or an entirety of each of the rotating step, the grout injecting step, the conveying step, and the pushing step is performed simultaneously.