Method for bored pile construction in high-latitude and extremely-cold permafrost region

The invention discloses a method for bored pile construction in a high-latitude and extremely-cold permafrost region. The method comprises steps as follows: (1) firstly, a field is leveled before construction, sundries in an operation area are cleaned, and the field is arranged; (2) guard barrels are buried, and sufficient wall protection mud or wall protection clay is prepared; (3) a measurement baseline and a base point are re-checked, and demarcated pile positions and the elevation are measured; (4) a drilling jig takes the position and is fixed; (5) a percussion drill is used for drilling and formation of holes, and the mud or the clay is poured into the holes for wall protection; (6) the depth of the percussion drill entering rock is controlled, and final hole identification is performed on the drilled holes; (7) the holes are cleaned, dregs are taken out, and the final hole diameter and depth are measured; (8) reinforcement cages are manufactured and mounted in final holes; (9) ducts for secondary hole cleaning are mounted in the final holes; (10) concrete is poured, and pile foundation inspection is performed. With the method, drilled hole walls are firm and stable; and equipment is simple in structure and is not limited by the field, the drilling efficiency can be significantly improved, and the construction cost can be saved.