Abstract: A systematic and practical method of calculation of internal forces and deformation of retaining structure for deep excavation is put forward; and by the method, the design of retaining structure for deep excavation can be perfectly finished. The method is applied to the deep excavation project of Guangzhou metro and other important projects; and it is proved to be effective and available .It simplifies the structure as an elastic beam on ground; and the braces, rock and soil are simplified as a spring system; the rock and soil springs can be express by the deformation modulus of the rock or soil. The systematic calculation method also includes the incremental calculation method that can be used to modeling the construction process, obtaining the embedding depth of the retaining structure reasonably; and it also can be used to modeling the preloading of the brace and the dismantling of the brace etc.. The famous Terzaghi-Peck apparent earth presure is firstly explained preferably by this method. The experiential calculated method for deformation modulus of soils by the bearing capacity is presented. The systematic calculation method provides an effect calculated method of retaining structure for deep excavation; and a series of key problems are solved preferably by the method. It is applied triumphantly in practice.

Key words: deep excavation, incremental method, interaction