Method for installing metal piles in permafrost soil

Abstract

A method for installing driven cast-in-situ supports of pipes, power transmission towers, and in the mounting of buildings and structures on permafrost soils excludes the ingress of slurry and groundwater into the hole when installing driven cast-in-situ piles in permafrost soils in summer having a thawed seasonal freezing and thawing layer while avoiding the impact of frost heaving forces of soil from seasonal freezing conditions. The method includes driving a casing pipe at a depth of seasonal freezing and thawing of soil, drilling a pilot hole at a depth of not less than the depth of seasonal freezing and thawing of the soil, pouring hardening material in the amount required to fill in the space between the pilot hole walls and the pile from the bottom of the pilot hole to the bottom of seasonal freezing and thawing soil layer, installation of the pile in the pilot hole and poured mortar, and filling the remaining space between the pile and the casing pipe with non-frost heaving loose inert material.

1 . A method for installing piles in permafrost soils, comprising:
 driving a casing pipe into soil to a depth of not less than a depth limit of seasonal freezing and thawing of the soil;   drilling a pilot hole to a depth of not less than the depth limit;   removing soil from an interior of the casing pipe;   pouring into the pilot hole an amount of cement and sand mortar that fills in space between walls of the pilot hole and the pile from a bottom of the pilot hole up to a bottom of a seasonal freezing and thawing soil layer;   installing a pile in the pilot hole with the cement and sand mortar; and   filling space between the pile and the casing pipe with non-frost heaving loose inert material.   
     
     
         2 . The method of  claim 1 , wherein the cement and sand mortar is in a range of M10 to M100. 
     
     
         3 . The method of  claim 1 , wherein the cement and sand mortar is in a range of M75 to M150. 
     
     
         4 . The method of  claim 1 , wherein the non-frost heaving loose inert material comprises at least one of coarse sand or medium sand. 
     
     
         5 . The method of  claim 1 , further compromising calculating a volume of the amount of cement and sand mortar by πR 1   2 *l 1 −πR 2   2 *l 2 , where R 1  is the radius of the pilot hole, l 1  is the length of the pilot hole; R 2  is the radius of the pile, l 2  is the length of the pile, and π is pi. 
     
     
         6 . The method of  claim 1 , wherein time between the pouring of cement and sand mortar and the installing of the pile does not exceed 15 minutes. 
     
     
         7 . The method of  claim 1 , wherein the casing pipe has a diameter that in greater than a diameter of the metal pile by an amount in a range of 10 to 20 cm. 
     
     
         8 . The method of  claim 1 , wherein the pilot hole has a diameter that is greater than a diameter of the metal pile by an amount in a range of 10-20 cm. 
     
     
         9 . The method of  claim 1 , wherein driving a casing pipe comprises driving the casing pipe to the depth in a range of 1.8 to 3 meters. 
     
     
         10 . The method of  claim 1 , wherein the casing pipe has a diameter in a range of 720 to 820 mm, a wall thickness in a range of 9 to 12 mm, and a length in a range of 1.8 to 3 meters. 
     
     
         11 . The method of  claim 10 , wherein the casing pipe is made of a material selected from: 17G1S, 17G1S-U, St2kp, St2ps, St2sp, St3kp, St3ps, St3sp, St3ps3, St3sp3, St3ps4, St3sp40, or 9G2S steel. 
     
     
         12 . The method of  claim 1 , wherein the pilot hole has a diameter in a range of 480 to 500 mm. 
     
     
         13 . The method of  claim 12 , wherein the pilot hole has a depth in a range of 6 to 20 meters. 
     
     
         14 . The method of  claim 13 , wherein the metal pile has a diameter of 426 mm. 
     
     
         15 . The method of  claim 13 , wherein the metal pile has a wall thickness in a range of 10 to 12 mm and a length in a range of 6 to 20 meters. 
     
     
         16 . The method of  claim 15 , wherein the metal pile is made of a material selected from: 17G1S, 17G1S-U, St2kp, St2ps, St2sp, St3kp, St3ps, St3sp, St3ps3, St3sp3, St3ps4, St3sp40, or 9G2S steel. 
     
     
         17 . The method of  claim 1 , wherein the removing soil comprises auguring. 
     
     
         18 . The method of  claim 17 , wherein the auguring is performed using an augur having a diameter in a range of 680 to 780 mm.