Graded hole forming construction method for super-large-diameter complex stratum

The invention relates to a super-large-diameter complex stratum grading hole forming construction method, which belongs to the field of foundations, and comprises the following steps: upper layer drilling: leveling a site, and drilling an upper soil layer and a weathered layer of a bedrock layer to a bedrock layer surface by using a rotary drilling rig; a rotary drilling rig is used for carrying out first-stage rotary drilling groove carving, the groove carving is carried out to the designed depth, and a rock core is formed; breaking and taking out the rock core by using coring equipment; second-stage rotary digging and groove carving are conducted, specifically, the rotary drilling rig is used for conducting second-stage rotary digging and groove carving, the groove is carved to the designed depth, and an annular bedrock layer is formed; and impacting and crushing the annular bedrock layer into holes by using a percussion drill. According to the graded hole-forming construction method for the super-large-dia