【正文】
are used to prevent retained material form assuming its natural slope. Wall structures are monly used to support earth, coal, ore piles, and water. Most retaining structures are vertical or nearly so。 however, if the a angle in the coulomb earthpressure coefficient is larger than 90176。 soil relies on friction stresses developed based on the angle of friction δ between soil and reinforcement or a bination of friction and passive resistance with soil and wire grids. The principle of reinforced earth is not new. Straw, bamboo rods, and similar alternative materials have long been used in technologically unsophisticated cultures to reinforce mud bricks and mud walls. Nevertheless, in spite of this long usage, French architect H. Vidal was able to obtain a patent (ca. mid1960s) on the general configuration of , which he termed “reinforced earth”. We see three basic ponents in this figure. ① the earth fill—usually select granular material with less than 15 percent passing sieve. ② reinforcement—strips or rods of metal, strips or sheets of geotextiles, wire grids, or chain link fencing or geogrids (grid