Working Mechanism And Analysis Of Finite Element Method Of Soil Nailing For Loess Foundation Pit

Soil nailing supporting is a new technology developed from abroad in recent years,to be used in excavation of soil,slope stability and the new retaining structure based on soil-bearing. The technique had been wide used in our country in nineties last century after it was introduced. However,the mechanism and performance of the new technique was not known yet at present,so the theory is behind the application.In this thesis, the developing history of soil nailing and its definition, classification, applicability and the open questions are presented. The working mechanism of soil nailing retaining system is also investigated systematically. Based on the analyses of the distribution rule of the horizontal displacement and the stretching force, the failure pattern and the stability analysis methods, the merits and shortcomings as well as the applicability of such kind of retaining structure are summarized. In addition, some technical problems in the construction and monitoring process are discussed.Secondly, the principle, method and specific content of the soil nailing design are introduced in detail. The calculation fundamentals of soil nailing is also analyzed and discussed. Moreover, some remarks on design and calculation are made for the current standard method and finite element method (FEM) related to soil nailing.Finally, a engineering example for loess deep foundation pit is given by using both the current standard method and the FEM. The soil deforming in the retaining structure, the ground surface settlement near the foundation ditch and the variation of the internal force of soil nail during the steps of excavation are calculated and analyzed. The retaining mechanism and working performance of soil nailing are further illustrated.The work presented herein can be used as the reference in the soil nailing design and the engineering applications.