RRR renders a high stability and minimizes deformation. It is applied to retaining wall systems up to considerable height. This Manual is intended for design and construction of GRS-RW system up to a maximum height of 10 m. Beyond this height, the design specialists should be consulted. For applications other than highways, related specifications and guidelines should also be consulted.

1. Features of 3R retaining wall systems and scope of application

a. Features of 3R retaining wall systems

FR Grid is a fiber net of highly strong vinyl fibers that have been immersed in resin.

FR Grid is reinforcing materials for RRR-method. 3R retaining wall has advantages as followings:

• Exhibit high strength, offering soil confinement and reinforced fill.
•  Perform high weathering, chemical, and thermal (cold and heat) resistance.
•  Perform high impact resistance.

Perform high creep properties

• Easy to construct and quality control. Be able to construct in smaller area in compare which tradition earth retaining wall.
• The amount of soil is significant lower in comparison with tradition earth retaining wall.
•  Retain the strength against the impact road of seism load and the repeated load of running train. ​

​a.    Scope of Application

Retaining 3R is applied in the following cases:

• Expansion of existing roads, constructions
• Using for positive and negative slope retaining walls
• Tunnel face strengthening
• Bridge pier and foundation strengthening

Applied technical specification

RRR renders a high stability and minimizes deformation. It is applicable to retaining wall systems up to considerable height. This Manual is intended for design and construction of GRS-RW system up to a maximum height of 10 m. Beyond this height, the design specialists should be consulted. For applications other than highways, related specifications and guidelines should also be consulted.

A list of relevant Japanese specifications and guidelines related to designing, constructing and inspecting are given below:

• Highway Bridge Specification, Vol. 4 – Substructures, Japan Highway Public Corporation.
• Specifications of Highway Earthwork, Retaining Walls, Culverts and Temporary Structures, Japan Highway Public Corporation
• Specifications of Structural Design of Building Foundation, Japan Architectural Society.
• Design and Construction Manual of Geotextile-Reinforced Soil Structures, Public Works Research Institute, Ministry of Construction

References:

• Design Standards for Soil Railway Structures, publisher Maruzen
• Design Standards for Concrete Railway Structures, publisher Maruzen
• Design Standards for Railway Structures – Foundation Structures and Retaining Structures, Japan Society of Civil Engineers
• Design Standard for Railway Structures – Reinforced Concrete and Unreinforced Concrete Structures, Japan Society of Civil Engineers
• Design and Construction Manual for Mixing Foundation, Japan Railway Technical Research Institute.
• Design and Construction Guidelines for Reinforced Soil Structures, Japan Railway Technical Research, Japan Railway Technical Research Institute.

Some pictures for 3R retaining wall applications