New ground improvement technologies under restricted conditions in Japan

Abstract

It is commonly understood in Japan that “drainage”, “compaction” and “solidification” are principles for ground improvement. Many ground improvement techniques have been developed to meet the demands of the times i.e. “economic efficiency”, “reliability (improvement effect)” and “environmental-friendliness”. However, some drawbacks of the methods have been eliminated, like the implementation system developed recently under the restricted condition to improve the limited space around the existing structures. This paper describes the relationship between the conventional and the innovative ground improvement methods followed by their aims of development in Japan. Furthermore, technical aspect of each innovative ground improvement method is outlined, such as “sand-injection type sand compaction pile method” and “twin-flow cement slurry jet mixing method”. Finally, the effectiveness of ground improvement technologies evaluated on their application examples near existing structure for the purpose of seismic reinforcement against natural hazard is reported.