The soft soil on the coast is improved with cement-based stabilizer. In recent years, seawater levels have rised due to global warming, and the salinity concentration of groundwater is increasing. It has been confirmed that calcium elutes when the cement-improved soil contacts with seawater. In this research, the long-term durability of the solidified soil in the coastal areas are clarified, and the integrity investigation and sustained repair method of the solidified soil are studied.

Trees have the ability to absorb emmited CO2 from the greenhouse gases and manitain their growth by photosynthesis action.
Futhermore, trees do not corrode in the ground depper than the groundwater level, so if they are used as the foundation of structures, they will be the foundation for storing CO2 underground semi-permannently. This study, would clarify the vertical bearing capacity of log spliced pile foundations using thinning, how to assemble raft-row pile composite foundations and their interaction with clayish ground. Eventully, The aim is to establish a design method.

Gabion is a traditional technology that has been a structural member, extensively used in water control work and earth retaining for a long time. Since material of gabion is only stone and wire mesh and it can be made manually, it is a technology with high applicability to developing countries. We investigate the stability of the gabion structure by conducting full-scale vibration experiments and model tests to verify the behavior of the gabion structure in detail, to propose more stable and advanced gabion structure design.

At the crush plants, where consturction materials are produced, by-products such as dehydrated cake and stone powder, which occurs as a residue of crushing the rocks as a construction product.From the viewpoint of effective use of resources, it is essintial to consider the use of these by-products. In this study, the strength and deformation characteristics of high-grade subgrade and subbase materials that can be applied to soft clayish ground are elucidated by using a dehydration cake with a high water content ratio and stone powder. Then, it would be studied how to make new materials and utilize them in future road pavements designs.