置換・締固め・固化による柱状地盤改良工法の現場適用事

In the conventional ground improvement method, the strength is exhibited by stirring and solidifying the solidifying material in the ground, so it is difficult to expect a strength higher than the solidifying potential of the solidifying material. In addition, because the soil is directly agitated with solidifying material in the in-situ, there is a concern that the strength may decrease due to the soil quality (physical and chemical properties) of the in-situ ground. In order to solve the above problems, the authors respected the basic principle of soil mechanics that soil becomes hard if voids between soil particles and water are eliminated. That is, the authors thought that the soil would harden by mixing particles of different sizes and compressing each other's particles with a strong force. Then, an original SST method was developed that allows the column to be constructed while compacting. The feature of the SST method is that it is possible to construct high quality columns on the ground where humus soil, that is unsuitable for applying the conventional ground improvement method, is deposited. In this study, the authors will take up two cases where the SST method is applied. As a result, it was clarified that high quality columns can be constructed by the SST method at two sites with different soil characteristics.