Abstract
Japan has 210,000 earth-fill dams and many of them are located in the Hyogo prefecture. These earth-fill dams were constructed over a long period of history, and damaged by earthquakes and typhoons. However, under reconstruction, there is a problem which is lack of suitable soil material for the core zone. Further, old earth-fill dams have large deposit of muddy soil.
In this paper, a method of creation of improved soil for impermeable core zone was proposed. The method was used some materials that should be recycled, for example muddy soil and old banking material. It is necessary to be said that the material is not only low cost but also mechanically stability and environmentally-friendly. In the laboratory, unconfined compression test and permeability test were conducted to clarify the best mixture fraction, and availability of quicklime and fly ash. Additionally, the field test was conducted. A large soil mixing machine was used to blend these materials, and it was tested for practical applicability since the improved soil for the impermeable core zone needs to be homogeneously-mixed. As the result of laboratory and field experiments, the improved soil made of muddy soil and old banking material had sufficient strength and impermeability. It was suggested that the improved soil could be reused when earth-fill dams were reconstructed.
