Fumio Tatsuoka is Visiting Professor of Tokyo University of Science while Professor Emeritus of University of Tokyo and Tokyo University of Science.He has been working on laboratory testing methods for geomaterials; deformation and strength characteristics of geomaterials; earthquake geotechnical engineering; foundation engineering; soil compaction; and ground improvement by cement-mixing and soil reinforcing, in particular geosynthetic-reinforcement. He has authored about 500 technical publications in English. He received a number of prestigious awards, including IGS Award; Mercer Lectureship; ASTM Hogentoglar Award(three times); Best Paper Award of the official IGS journals (Geosynthetics International and Geotextiles & Geomembranes) (multiple times); and first ISSMGE Bishop Lectureship. He served as Vice President of Japanese Society for Civil Engineers, President of Japanese Geotechnical Society, Vice President of ISSMGE; President of IGS and others. He was the chairperson of the organizing committee for 8ICG Yokohama 2006.
This lecture reports various types of geosynthetic-reinforced soil (GRS) structures developed and constructed mainly for ordinary and high-speed railwaysfor the last thirty years in Japan. Based on extensive research during 1980’s, GRS Retaining Wall (RW) with full-height rigid (FHR) facing was developed. The FHR facing is constructed firmly connected to the wrapped-around wall face of GRS wall after the deformation of supporting ground and reinforced backfill has taken place sufficiently. The first wall was constructed in 1989 and the total wall length became more than 170 kmin 2017.In the early 1990’s, based on this GRS RW technology, GRS Bridge Abutment supporting a bridge girder via a hinge bearing on the top end of the FHR facing of a GRS RW was developed. More than 60 have been constructed. In the early 2000’s,based on GRS Bridge Abutment technology, GRS Integral Bridge was developed, where both ends of a continuous girder are integrated to the top ends of a pair of FHR facings of GRS RW. Five with the longest span being 60 m have been constructed by 2014. GRS Box Culvert, integrated to GRS RWs on the both sides, and GRS Tunnel Exit Protection were also developed and constructed. In addition to those described above, for a new high-speed railway (Nagasaki Line) in Kyushu Island, Japan, which is now under construction, a number of these GRS structure types are under construction, or to be constructed: i.e., GRS RWs for a total length of 4,988 m; 80 GRS Bridge Abutments; seven GRS Integral Bridges with the longest span being 40 m; and 55 GRS Tunnel Exit Protections. Importantly, most of these GRS structures are constructed in place of conventional type structures (i.e., sloped unreinforced embankments; cantilever RC RWs; RC bridge abutments with unreinforced backfill supporting a girder via bearings; and ordinary simple-supported bridges with unreinforced backfill; and RC tunnel exit structures). This report summarizes lessons learned from research, experiences withplanning, design and construction and performance of these GRS structures.