CONSTRUCTION METHOD FOR IMPROVING BEARING CAPACITY OF PILE FOUNDATION ON BASIS OF LARGE-DIAMETER MIXING

Disclosed is a construction method for improving the bearing capacity of a pile foundation on the basis of large-diameter mixing, belonging to the technical field of pile foundation construction. On the basis of a mixing drill bit, which is provided with mixing jet nozzles and high-pressure rotary jet-grouting nozzles at the back of a mixing blade, combined with a mixing drilling machine, the large-diameter deep-layer mixing construction method is implemented by means of the following steps: performing configuration and modification for a mixing apparatus; preparing jet-mixing pulp and rotary jet-grouting pulp; performing mixing drill-down construction; performing mixing drill-lift construction; completing a mixing operation, and performing a pile planting operation; and finishing construction. By means of the configuration of multiple jet-mixing nozzles and high-pressure rotary jet-grouting nozzles, the diameter of the mixing pile is expanded, and a tubular pile is inserted to achieve high strength; by means