Reinforced earth

The relatively new concept of reinforced earth makes extensive use of galvanized steel rods or strips. The subject is well covered by the British 

Standards Institution s PD 6517 (1988). An earlier review (King, 1977) with 86 references covers soil corrosiveness with particular reference to reinforced earth. 

Reinforced earth is a composite of soil and tensile- or shear-resistant inclusions that function through the agency of direct soil-reinforcement interaction to produce a material having a performance superior to that of soil alone. Reinforced earth may be used to replace conventional structures, to reduce area of land required, or to build flexible structures over poor or soft foundations. 

Reinforced earth walls are commonly used for some form of soil retention. For example, a vertical face constructed without reinforcement would fail in time, depending on the value of the soil parameters. If the soil in the region of the face is reinforced, however, it will form a stable mass, which can support the unreinforced soil behind it. The same principle applies to reinforced slopes constructed to an angle steeper than their angle of internal friction. 

The advantage of a reinforced fill-retaining structure over a reinforced concrete wall is that the inherent resilience and flexibility of the composite enables construction to progress with a minimum of treatment of the foundation soils, where subsequent movements are likely. There is some similarity to the principle of reinforced concrete in that the reinforced mass may be considered to be a composite material with improved properties, particularly in tension, compared with the soil or concrete alone. 

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Two civil engineering operations require particular attention when soil corrosion tests in the field are required. These are (1) the use of reinforced earth structures in which the corrosion conditions will differ from those at... 

Principal countries where Reinforced Earth has been used... 

Measures to control rockfall include catch fences, benches, wire mesh and rock traps. Restraining structures control landslides by increasing the resistance to movement. They include, for example, retaining walls, reinforced earth structures, shotcrete, cribs, gabions, buttresses, piling, dowels, rock bolts and rock anchors (see Chapter 9). The following minimum information is required to determine the type and size of a restraining structure ... 

Reinforced earth being used aiong the A82 road in Scotiand. 

The form of the early structures comprised a U-shaped sheet metal or plastic facing panel connected to metal strips, usually made of galvanized steel. The reinforcement of the soil is the consequence of tensile forces in the reinforcement being generated by friction between the soil and the strips. This composite material was called Terre Armee (reinforced earth) by Henri Vidal, who introduced it. 

Conversely, reinforced earth applications of galvanized steel have been extensively documented Tables 4.8 and 4.9 list selected projects that have performed satisfactorily for 12-20 years. By 1982, 2500 projects had been completed in 37 countries (R. J. H. Smith, 1982), and by 1989 there were 13,500 structures totaling 7.7 x 10 m (Jailloux, 1990). One of the first uses... 

Darbin, M., Jailloux, J. M., and Montuelle, J. (1988). Durability of reinforced earth structures The results of a long-term study conducted on galvanized steel. Proc. Inst. Civil Eng., Part 1, 84, 1029-1057. 

McKittrick, D. P. (1979). Reinforced earth Application of theory and research to practice. Reprint from Ground Eng., 12 January, 12 pp. 

Smith, R. J. H. (1982). Construction of reinforced earth structures. Conf. Construction Practices Engineering, Surat, India, pp. 119-124. 

MSE walls are a kind of reinforced earth-retaining structure. By installing multiple layers of high-strength fibers inside of the fill section, the friction and interlock mechanism between the fibers and backfilled soil will effectively restrict the lateral deflection of the filled soil body. Hence, the MSE wall is a compacted soil body acting as one gravity wall. Because every bit of the MSE waU material is reinforced-compacted soil, this system should be used on topography fill locations only. 

Reinforced earth-retaining structures with strip/sheet-polymer/metallic reinforcement elements... 

Evidently, there are three important mechanical properties of a geotextile used for reinforcement tensile modulus, tensile strength, and surface friction. The puU out test is a common one for determining the strength and deformation parameters between the reinforcement and the soil in the design of reinforced earth stmctures (Adanur ... 

Oioukeir M, Juran I, Hanna S (1997) Seismic design of reinforced-earth and soil-nailed structures. Ground hnprov 1 223—238... 

Holtz, R.D., Massarsch, K.R., 1976. Improvement of the stability of an embankment by piling and reinforced Earth. In Proc. 6 European Conference on Soil Mechanics and Foundation Engineering, Vienna, Austria, vol. 1.2, pp. 473—478. 

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