Recent trend and application of soil mixing deep wall

A vertical soil deep mixing wall, known as the TRD (Trench cutting Remixing Deep wall) method was developed in Japan in the early 1990s as a technology for constructing soil cement diaphragm continuous underground walls. In this method, a cutter post built into the ground is moved laterally to excavate the ground with a cutter bit attached to a cutter chain, while mixing and stirring the solidified liquid and in-situ soil in a vertical direction to create a wall-like solidified body in the ground. One of the characteristics of this method is the continuity of the wall and high water sealing performance due to its unique excavation mechanism, and it is applied not only to earth retaining walls but also to impervious walls such as impervious revetments and underground counterfort revetments, as well as to containment of contaminated soil. In recent years, a new type of TRD has been developed that enables the construction of walls as wide as 900-1200 mm, in contrast to the 450-850 mm wall thickness of the conventional type. This paper describes a case study of the application of the wide type of TRD method to an earth retaining wall of a ditched road, in addition to the outline and development history of the TRD method.