Nail-Reinforced Soil (NRS) Retaining Wall

RRR-C is a new technology to cut natural slopes or embankment slopes to near-vertical walls by using large-diameter nails and FHR (full-height rigid ) facing without using temporary structures (e.g., anchored sheet piles). New spaces are created in front of the wall.
Firstly, an internal FHR wall is installed in the slope before the start of step by step cutting. At each step, large-diameter nails are installed after partially cutting the slope. In this way, the deformation of slope during cutting is kept very small, which allows continuous use of the slope crest for railways, highways, residences etc. After cutting is completed, an external FHR facing is constructed by casting-in-place concrete on the wall face in such manner that it is firmly connected to large-diameter nails. The completed wall is very stable. Moreover, the FHR facing can be used as a foundation for other structures (e.g., fences, traffic barriers, noise/wind barriers, electric power supply poles etc.).

Shinkansen (bullet train)

Nail-reinforced soil wall under construction, Kyushu Shinkansen, 2000
Nail-reinforced soil wall under construction, Tohoku Shinkansen, 2000


Completed Nail-reinforced soil wall, Chojabaru Station, JR Kyushu Sasaguri Line, 1999
Quadruple-track work between Musashikosugi and Hiyoshi on Tokyu Toyoko Line, constructed 2004