Temporary cutoff method, temporary cutoff structure, support work, support work unit

摘要

PROBLEM TO BE SOLVED: To provide a temporary cut-off method that contributes to improvement of workability during construction of a structure in water area and quality of the structure.SOLUTION: A water area 3 is cut off by a well-like steel pipe sheet pile 4, then the inside of the well formed of the steel pipe sheet pile 4 is bored underwater. After a truss supporting 1 is installed in the well and dried up, a structure is constructed. The truss supporting 1 has an annular flat surface in substantially hollow square shape along the inner periphery of the well formed of the steel pipe sheet pile 4, an opening 15 at its central part, and a truss structure in flat. The truss supporting 1 is installed in vertically plural steps. The truss supporting 1 formed of upper and lower two steps is vertically connected by the truss structure.SELECTED DRAWING: Figure 4