The social capital of Japan has been greatly improved since the record period of economic growth, the number of buildings and public facilities built over 50 years ago has been increasing. In order to pass on the benefits of infrastructure development to the next generation, an appropriate renewal plan is necessary. Looking at cities, the lack of vacancies in office buildings and accommodation facilities is on the rise, due to the increase in the number of foreign visitors to Japan and the highly concentrated of large company headquarters across Japan metropolitan areas. However, while satellite cities around metropolitan area are becoming desolate, cities are progressing redevelopment. From now on, cities, with the desire to develop and use land resources effectively, need to conduct reconstruction of infrastructure.
Along with the renovation of cities, old buildings are being dismantled, leading to the removal of old pile foundations. In particular, eliminating existing large-diameter cast-in-place pile by using an all-rotation excavator to cut vertically along the length of the pile. In this case, because the pile is vertically cut along the length, the weight may be too large to be removed from the ground. If it cannot be taken out, the pile will be crushed into small pieces, however, because the size of the shredded pile in the casing cannot be predicted in many cases, it often exceeds the crane lifting capacity. For these reasons, work progress was often unstable, and the removal of existing cast-in-place piles from the ground also faces environmental, safety and cost problems.
To solve this problem, a construction method that can cut existing piles horizontally has been desired.