Recent Practice and Research of Geosynthetic-Reinforced Earth Structures in Japan

Abstract

The construction of permanent geosynthetic-reinforced soil (GRS) retaining walls (RWs) with a full-height rigid facing for railways, including high-speed train lines, and also highways started about twenty years ago in Japan. The total length of this type of GRS RW is now more than 100 km, replacing traditional cantilever reinforced concrete RWs and steel-reinforced soil RWs. Although most of the new type GRS RWs are new walls, many were also constructed replacing traditional type RWs and embankments that collapsed during recent earthquakes and heavy rainfalls. Several case histories typical of the newly constructed GRS RWs and those constructed to replace collapsed traditional type RWs and embankments are presented. By taking advantages of this technology, a number of bridge abutments with geosynthetic-reinforced backfill were constructed. The latest version, called the GRS integral bridge, comprises a continuous girder integrated to a pair of RC facing with the backfill reinforced with geosynthetic reinforcement layers firmly connected to the back of the facing. Results from static and dynamic model tests that show advantages of the GRS integral bridge are presented.