Ground improvement construction machine and ground improvement method suitable for construction in confined spaces

摘要

PROBLEM TO BE SOLVED: To provide a compact ground improvement construction machine which is suitable for performing ground improvement construction for liquefaction prevention to a narrow residential district whose construction space receives various constraints and a ground improvement method for inexpensively constructing a lattice ground improvement wall or the like by using the construction machine.SOLUTION: A mechanical agitation type ground improvement process is advanced downward, the process of elevating a rotary drive part 6 and rotary power devices 7 and 8 at a fixed stroke by elevating/lowering driving parts 31 and 41, and fixing and supporting a drive shaft 5 by the rotary drive part 6, and lowering while rotationally driving the rotary drive part 6, and carrying out the drilling of the ground and solidification material slurry injection. Furthermore, a ground improvement process step is repeatedly advanced until a target depth, the step of, when an elevating/lowering driving part 41 is lowered to a lower limit position, temporarily releasing the fixing and support of the drive shaft 5 by the rotary drive part 6, and elevating the rotary drive part 6 at a fixed stroke, and fixing and supporting the drive shaft 5 by the rotary drive part 6 again at an elevating position, and lowering while rotationally driving the rotary drive part 6.