Analysis On Safety Coefficient Of Reinforced Earth Structure With FEM Strength Reduction

The Earth reinforcement technique is defined as the inclusion of resistant element in a soil mass to improve its mechanical properties. Because of convenient construction, low cost and so on, it has been highly developed both in the domestic and overseas, and has been widely used in embankment, retaining wall, slope and foundation.Sand is always thought to be the premier to select and has been used in most reinforced earth engineering by reason of its high permeability and making greater friction. However, in practical projects, other materials such as glutinous soil, fly ash are also used in view of geographical limit and project cost, and make success, but theory analysis is not perfect . So, in this paper, the characterisitics of the glutinous soil is introduced; the interaction characteristics of glutinous soil and geogrid are summarized. The notice is pointed out in construction of the glutinous soil.In the paper, the author sums up the main calculation methods of reinforced earth structure, and points out the disadvantages of methods in being and advantages of FEM. The method of FEM strength reduction is introduced in detail and interrelated problems are discussed. With the method, the author analyzes the stability of a reinforced earth retaining wall filled by sand and glutinous soil respectively and an embankment, gets the safety coefficient and the failure surface. So, the method of FEM strength reduction can not only meet force equilibrium, but also can take into account the relationship of stress and strain , the reciprocity of the filling and geogrid, besides, it can get the distribution of stress and strain under load as well as actual failure surface. Another problem is that traditional methods, such as Sweden method and Holland's method are unduly conservative in the stability analysis of reinforced embankment, however , the method of FEM strength reduction can improve it.