Research On The Working Mechanism And Engineering Application Of Soil Nailing

The excavation engineering is an antiquated and modern geotechnical engineering problem. With the continuous development of the industry and urban construction, the scarcity of the city ground, the exploitation of the underground space receives recognition. With the increasing of the deep excavation project, people do much study of the bracing methods. Thereinto the soil nailing is adored as the special excellence for example the convenience, the expeditiousness and the cheapness etc. However, the actual working mechanism of the soil nailing is still unknown, and the theory about soil nailing does not match its application in the engineering. At the base of analyzing and summarizing the research results of the last, the author obtains some research results. I hope that it can provide the beneficial leading to the research and application of soil nailing structure.Above all, the thesis analyses the conception of soil nailing, and define it. The thesis introduces the general situation about the soil nailing development on the different country; the investigation actuality; the advantage and the disadvantage. The working mechanism and capability of soil nailing retaining system is also investigated systematically. At the base of the research results of the last, different mechanics models are utilized to analyze the theory mechanism of the soil nailing pulling-resistance test; research internal force and displacement of soil nails under normal condition of work; and transverse anti-shearing effect of soil nailing. It summarizes the friction reinforcement principle of earth, soil arching effect and apparent cohesion theory.The author tries to analyze the stableness of the soil nailing in the process of the foundation pit excavation. To the interior stableness analyses, according to the energy method and taking into account the transverse anti-shearing effect of soil nailing, the formula of safety factor in limit equilibrium based on the log-spiral failure mode is constructed. In order to found the optimal mode to make the value of target function minimum, the author uses safety factor as target function and searched for the dangerous slip-face, and concluded the sensitivity of all parameters to the stable factor. It summarizes the soil nailing design process and method. The principle, method and specific content of the soil nailing design are introduced in detail. Moreover, some remarks on design and calculation are made for the current standard method and finite element method (FEM) related to soil nailing.The thesis summarizes the construction method. The advertent point, ordinary problem and the disposal about the soil nailing construction are brought forward. In addition, it puts forward the request and plan about the transmutation supervision. Finally, an engineering example in Fuzhou is given to analyze it. The retaining mechanism and working performance of soil nailing are further illustrated.The article can be used as the reference in the soil nailing design and the engineering applications.