Parametric Nonlinear Design Methods Of Subway Shield Segments

As the increasingly severe pressure of urban traffic,subway has become the main direction of development of urban transport.Shield tunnel has been widely used in China because of safety,construction speed,etc.The cost of shield segments accounted for 40%of project cost.But how to choose the design parameters of the tunnel segments is generally referring to some of the similar projects,or use the experienced value.There is no design specification for the shield segment,It's hard to get shield segment both reasonable and economical.In this paper,we made a parametric analysis about the design of tunnel segments.In this paper,Shield technology development history and current situation and the different design methods tunnel segments at home and abroad the are introduced at first.Based on the the current domestic situation for design,a detailed description of the situation how the design parameters are be selected has been made.The thickness of segment,the width of segment,bending stiffness and the ground resistance coefficient have been selected as the key design parameters.And a detailed description of load in the shield project has been made.There are two design methods of the underground structures that are recognized and can be widely used:Load-Structure and Stratum-Structure.And the Load-Structure are more popular.A detailed description has been made about four design methods:idioms,correction idioms,multi-hinge ring method and beam hinges-spring model method.And the formulas and computational theory in the correction idioms which is widely used has been introduced in detail.Finite element software ABAQUS has been used to establish calculation model in this paper.Three-dimensional solid elements were used in the model.Research and analysis has been made about the how the Moment,axis force and displacement of the lining are influenced by the thickness of segment,the width of segment,bending stiffness and the ground resistance coefficient which are the key design parameters.The summary and corresponding conclusions has been made with the results of numerical calculation.And fitting diagrams and fitting formula are made which could be used as the reference for the lining segment design.With the study of the above problems,the paper not only is the instructive significance to lining segment design,but also provides a basis for discussion and technical support about how to choose the design parameters in the shield tunnel design in the future.