CULVERT BELOW BANKING

PROBLEM TO BE SOLVED: To eliminate a work to effect rolling compaction and excavation of the internal part of a tunnel by a method wherein a wall body and PV plates are previously arranged in a spot positioned on the inner surface of a tunnel built below a banking. SOLUTION: A wall body 11 being a conrete skin is built on a foundation 14 at other part than an arch-form tunnel top part and a plurality of belt-like reinforcing material 13 made of a steel are vertically horizontally arranged on the outside of the wall body 11. A part forming an artificial soft rock ring (a reinforced soil ring) 9 is filled with a mixture material (soil cement) of cement and an aggregate and simultaneously the outside thereof is filled with general soil 10. A precast plate 12 is then erected at the arch-form top part of a tunnel in succession to the upper part of the wall body 11 and finally, soil cement is also placed on the outside of the precast plate 12 in succession to the upper part of soil cement placed on the outside of the wall body 11 and by constructing the artificial soft rock ring 9, culvert 8 below a banking is built.