METHOD AND APPARATUS FOR IMPROVING BEARING STRENGTH OF PILES IN PERMAFROST

• US 3,706,204 A
• Filed: 02/10/1971
• Issued: 12/19/1972
• Est. Priority Date: 02/10/1971
• Status: Expired due to Term

• Current Assignee: Erwin L. Long
• Original Assignee: Erwin L. Long
• Inventors: Long, Erwin L.
• Primary Examiner(s): Shapiro, Jacob
• Application Number:
  US05/114,258
• Time in Patent Office: 678 Days
• Field of Search: 61/53,53.5,53.52,53.64,53.68,56,36A 165/45
• US Class Current: 405/130
• CPC Class Codes: E02D 27/32 Foundations for special purposes for paving of roads E01C3/00
• CPC Class Codes: E02D 27/35 Foundations formed in frozen ground, e.g. in permafrost soil
• CPC Class Codes: E02D 5/28 made of steel or other metals E02D5/52 takes precedence
• CPC Class Codes: E02D 5/54 Piles with prefabricated supports or anchoring parts; Anchoring piles E02D5/44 takes precedence; ground anchors E02D5/80; anchored foundations E02D27/50

Abstract

A pile has a lower portion insertible into the permafrost or permanently frozen region of the soil, an intermediate portion extending through the seasonal frost or seasonal-thaw region and an upper portion exposed to the atmosphere above the soil. The lower portion is provided with cylindrical or segmented cylindrical rings which extend radially outwardly beyond the surface of the pile. The piles are used in a method of improving the bearing strength of the pile by inserting into a hole down into the permanently frozen region a pile having laterally extending rings or segments of rings on its lower portion below the seasonal-thaw region and then filling the hole surrounding the pile with fill material which eventually freezes and becomes an integral part of the permafrost soil surrounding the hole.

Claims

1. A method of increasing the bearing strength of a pile in soil having a permanently frozen region and a seasonal-thaw region comprising adding lateral appendages to a pile, providing a hole of a diameter substantially greater than the diameter of the lateral appendages on the pile and surrounded by a permanently frozen region and a seasonal-thaw region above the permanently frozen region, inserting the pile in the hole to a depth in which the appendages are below the seasonal-thaw region, filling the hole around the pile and the perimeter of the appendages to provide a stable unsheared surface between the pile and appendages and the sidewalls of the hole, and freezing the fill material in the hole to provide an integral bond between the appendages, fill material and permafrost soil surrounding the hole.

2. The method of claim 1 wherein the material in the hole around the pile has a lower salinity than that of the permafrost soil.

3. The method of claim 1 wherein the fill material in the hole around the pile has a shear strength greater than the permafrost soil surrounding the hole.

4. The method of claim 1 wherein the top of the pile is exposed to the atmosphere and the pile is of a type that removes heat from the permafrost and fill material so that the temperature is lowered in the fill material to increase its shear strength at the lateral edges of the appendages.