Abstract:A vertical shaft is a crucial part of underwater tunnel passing river or sea. A vertical shaft in a slender shape should be designed in different manners compared with the longitudinally slender structures such as tunnels. In the aspect of cross-section,the shaft is generally designed in a circular shape in spite of the fact that the rectangular type has more versatile usage of space. Besides,when a structure is constructed under river or sea,the open caissons designed in circular shape are adopted as for the foundation of the structures. However,this is outweighed by far the considerable advantages offered by the reduction of external pressure due to the arching effects in a horizontal plane. The wall stiffness,construction method and construction management during the construction of the support walls have an effect on the amount of wall displacement. In addition,development of cut wall displacement is essential even if the rigid lateral support such as a slurry wall is installed. Therefore,it has been recognized that the ground pressure on the cylindrical retaining wall is between the at-rest and active ground pressures under plane strain condition because of the stress relief,horizontal and vertical arching effects during excavation. The ground pressure distribution and the shape of failure surface by conducting model tests for the cylindrical retaining wall of a shaft in cohesionless soils are discussed.