Negative friction pile and isolating casing

Claim 2

A skin friction pile for driven support in positive skin friction soil to raise and support or underpin a building structure, said pile comprising a plurality of pile sections in end-to-end abutting relationship, said pile sections being connected together by internal couplings secured in the pile sections, and a casing independent of said skin friction pile surrounding certain said pile sections in negative friction soil, said casing comprising a plurality of casing sections in end-to-end abutting relationship having minimum clearance around the pile sections in the range of approximately 1/64 inch to approximately 5/32 inch, said skin friction pile extending to depths substantially greater than said casing for support solely in positive skin friction soil by positive skin friction only of such soil bearing on the pile, said casing extending to a lesser depth than said skin friction pile through negative friction soil and isolating said certain pile sections from said negative friction soil, said minimum clearance repelling the entrance of soil between the pile sections and the casing sections thereby enabling the pile sections to be driven to greater depths than said casing sections.

Claim 3

A skin friction pile as set forth in claim 1 wherein said pile sections and said casing sections are disposed at the same level at their upper ends for simultaneous driving by a single driving means.

Claim 4

A skin friction pile as set forth in claim 2 wherein means are provided connecting the upper end of said pile to said building structure for continuing support thereof, said means including a hydraulic pressure unit, a reaction member for said hydraulic unit, a mounting bracket attached to the building structure and extending substantially beyond opposite sides of said pile for attachment to said structure over a wide area, a connecting member between said reaction member and said mounting bracket, and means to adjust the reaction member on the connecting member whereby the connection of said pile to the building may be relatively adjustable.

Claim 5

A skin friction pile for driven support in positive skin friction soil to raise and support or underpin a building structure, said pile comprising a plurality of pile sections in end-to-end abutting relationship, said pile sections being connected together by internal couplings secured in the pile sections, a casing independent of said skin friction pile surrounding certain said pile sections in negative friction soil, said casing comprising a plurality of casing sections in end-to-end abutting relationship having a predetermined clearance around the pile sections, said skin friction pile extending to depths substantially greater than said casing for support solely in positive skin friction soil by positive skin friction only of such soil bearing on the pile, said casing extending to a lesser depth than said skin friction pile through negative friction soil and isolating said certain pile sections from said negative friction soil, and a seal member secured to the bottom end of the bottom casing section having an outside diameter substantially coincident with the casing and an inside diameter substantially similar to the outside diameter of said skin friction pile, said seal member repelling the entrance of soil between the pile sections and the casing sections at the bottom end of the casing thereby enabling the pile sections to be driven to greater depths than said casing sections.

Claim 6

A skin friction pile for driven support in positive skin friction soil to raise and support or underpin a building structure, said pile comprising a plurality of pile sections in end-to-end abutting relationship, said pile sections being connected together by internal couplings secured in the pile sections, a casing independent of said skin friction pile surrounding certain said pile sections in negative friction soil, said casing comprising a plurality of casing sections in end-to-end abutting relationship having a predetermined clearance around the pile sections, said skin friction pile extending to depths substantially greater than said casing for support solely in positive skin friction soil by positive skin friction only of such soil bearing on the pile, said casing extending to a lesser depth than said skin friction pile through negative friction soil and isolating said certain pile sections from said negative friction soil, and a seal member secured to the bottom end of the bottom casing section having an outside diameter substantially coincident with the casing and an inside diameter substantially similar to the outside diameter of said skin friction pile, said seal member repelling the entrance of soil between the pile sections and the casing sections at the bottom end of the casing thereby enabling the pile sections to be driven to greater depths than said casing sections.

Claim 7

A skin friction pile as set forth in claim 4 wherein a seal member is secured to one or more of said casing sections above said bottom casing section.

Claim 8

A skin friction pile as set forth in claim 4 wherein a gasket is secured to said seal member in sealing engagement with said pile.