CAISSON SINKING METHOD

PURPOSE:To easily sink a caisson body to a determined depth by continuing excavating work while leaking a high pressure air sealed in an excavating work chamber formed on the lower side of a pressure bulkhead into an inside box body. CONSTITUTION:A caisson body 20 formed of inside box bodies 11..., outside box bodies 12..., and vertical walls 13... vertically partitioning them is built in a caisson sinking area in such a manner as to be capable of sinking. Then, the inside box bodies 11... and outside box bodies 12... divided into a number of pieces by the vertical walls 13... are mutually sealed by pressure bulkheads 14, 14, whereby a number of excavating work chambers 15, 15 having a high pressure air sealed structure are formed on the lower side of the pressure bulkheads 14, 14. Excavation work is continued to sink the caisson body 20 to a determined depth while leaking the high pressure air sealed in the excavation work chambers 15, 15 into the inside box bodies 11... through air passages 16, 16 provided on the lower edges of the inside box bodies 11...