Masaki Kitazume Graduated from Tokyo Institute of Technology in 1979, and obtained Master of Engineering in 1981. Then, he joined the Port and Harbour Research Institute, Ministry of Transport and had been in charge of the head of the Soil Stabilization laboratory and had worked the interaction of improved ground and soft ground. In 1994, he got a Doctor of Engineering from Tokyo Institute Technology on the design of stability of Deep Mixing improved ground. In 2011, he was invited to professor of Department of Civil and Environmental Engineering, Tokyo Institute of Technology.

He has published many papers, mainly on the geotechnical aspects of soil stabilization, ground improvement and centrifuge model testing. He also published three books from Balkema Publishers and Taylor & Francis, on Deep Mixing Method, Sand Compaction Pile Method and Pneumatic Flow Mixing Method.

He was awarded the Geotechnical Engineering Development award from the Japanese Society of Soil Mechanics and Foundation engineering in 1992, the Minister of Transport Award in 2000, and Continuing International Contribution Awards, Japan Society of Civil Engineers in 2006, Geotechnical Engineering Research Achievements Award, the Japanese Society of Soil Mechanics and Foundation engineering in 2018, and Telford Premium Prize, ICE Awards, 2019.

World-wide globalization has enhanced the international trading and has promoted many land reclamation projects at coastal area for port and airport facilities, power plant, manufacture plant, residential area and so on in many countries. Land reclamation requires a large amount of fill soil, which is usually obtained by cutting mountain or excavating river and seabed. Recently it becomes difficult to obtain such a soil with reasonable expense because of restrict environmental protection.

A large amount of soft soil is dredged at many ports every year to maintain enough sea route depth and sea berth. These dredged soils are used to be dumped at disposal sites. It becomes difficult to construct the disposal area for dredged soil and subsoils, because of environmental restriction and economical reason. As dredged soil usually has a high water content of the order of hundreds percent, reclaimed land constructed with it is so soft and highly compressible that no superstructure can be constructed without any ground improvement. Vertical drain method is one of the most frequently used ground improvement techniques to improve such a soft soil. However the method requires relatively long period to complete the consolidation.

These circumstances have promoted the development of sustainable land reclamation method for beneficial use of dredged soft soil as a fill material. As one of the sustainable land reclamation techniques, Pneumatic Flow Mixing Method has been developed in Japan, in which dredged soft soil is mixed with binder, usually cement, in a pipeline during transporting them to reclaimed site by compressed air. The mixture of soft soil and binder forms many separated soil blocks in the transporting pipeline, and are thoroughly mixed during transporting by the help of turbulent flow generating within the soil block. Extensive laboratory and field researches were carried out to study the applicability of the method for land reclamation through the investigations of stabilized soil properties, construction techniques, executing ability, quality control and assurance and so on. Many construction firms have also performed research works to develop their own technique. These research efforts have revealed the high applicability of the method for land reclamation and promoted several construction projects. This method was applied to construct a man-made island for Central Japan International Airport at Nagoya area and Tokyo/Haneda International Airport.

This presentation briefly introduces the Pneumatic Flow Mixing Method and its applications as well as the mechanical properties of the stabilized soil, the execution technique, in order to emphasize the sustainable land reclamation method.