Abstract: Setting earth berm before retaining structure can reduce effectively its internal force, deformation and embedded depth, and achieve good economic and environmental benefits. Based on various technical codes for excavation engineering can’t provide the design and calculation of the earth berm, and very few research this problem and the point of view is not uniform in geotechnical engineering field, the past calculation methods of earth berm is collated and analyzed firstly, and four categories are induced: (1) adding load before the retaining structure; (2) subsidiary stress of Boussinesq approximation; (3) improved elastic foundation beam method; (4) whole finite element collaborative computing, then the doubts, key points and applicable conditions in these methods are pointed out; next the mechanism of earth berm is summarized. At last, based on elastic foundation beam theory, a new simplified method to analyze earth berm is proposed, which used pressure springs and overload to simulate the back pressure effect, and by comparative calculating of setting earth berm, not setting earth berm, reinforcing earth berm in an excavation engineering, the rationality of this method is verified; and it can provide reference for design and construction of retaining engineering.

Key words: retaining structure, earth berm, elastic foundation beam, foundation pit engineering, calculation method