This paper gives a general review on the deformation pattern of the longitudinal structure of shield tunnel and the existing analytical models. Based on the previous studies, two longitudinal deformation modes are identified: i) bending deformation mode, and ii) dislocation mode. The longitudinal deformation of tunnel should consist of both flexural deformation under bending and dislocation between segmental rings under shear force. The existing analysis models of longitudinal structure mainly include i) segment ring-joint model and ii) longitudinal equivalent continuous model. The former can theoretically reflect the features of the tunnel structure. However, it is difficult to be applied in tunnel analyses as some of the parameters (e.g. joint stiffness) are difficult to determine in engineering practice and the calculation is very complicated. By contrast, the longitudinal continuous model is clearer in concept and simpler in calculation, which makes it widely adopted by researchers. The existing longitudinal continuous model follows the Euler-Bernoulli theory and therefore only considers the flexural deformation under bending; the dislocation between segmental rings is not taken into account. Elastic foundation model is widely used in the analysis of the interaction of tunnel and soil. Typical elastic foundation models include Winkler model, elastic continuous medium model, and two-parameter model. Winkler model is the most popular model due to its simplicity in calculation. Two parameters model, which considers the continuity of soil, is more accurate than Winkler model.

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In Japan, the construction of social infrastructure has been increasing since the high eco-nomic growth in the 1960s. Right now it is a problem in Japan that these infrastructures are deteriorat-ing. It is expected that further deterioration will occur in the future so the maintenance and operation for these infrastructures is now a signifi-cant subject.Under these circumstances, a managing method named as an infrastructure asset management is beginning to be employed recently. Infrastructure asset management is a strategic management of physical assets during their life in the organization, which enables us to manage physical assets effectively and efficiently. The goal is to conduct a mid and long term efficient maintenance and operation plan for the subway tunnels and to decide the proper budget for rehabilitation.

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The surface settlement (SS) induced by shield tunneling method can be predicted using the modified Peck formula based on the modified gap parameters proposed in this work. The modified gap parameters considered shield tunneling parameters (STPs) can be expressed with the support pressure ratio of shield (λ), fill rate of grouting (β), and eccentricity ratio of shield (κ). Based on the actual cases of the Xi’an subway line 2 in China, the results of sensitivity and back analysis of STPs show that β has a minimal effect on SS, λ has a significant influence on SS, and κ has the maximum effect on SS. The maximum SS and surface curvature due to shield tunneling are be considered to control the permitted deformation according to the Chinese standards. Thus the control standards of STPs are obtained and suggested through the back analysis of damage classification by using the modified Peck formula.

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Underpass tunnels are often constructed on the bottom of railway. For preventing a relaxation of natural ground by excavation, box form roofs are set around the area in which the underpass tunnel will be constructed. However, in some cases, box form roofs are gradually bended on bolted joints by both an earth pressure and railway load. It is needed for constructing underpass tunnels safely to manage the torque of bolts in the box form roof. Torque managements of bolts are a valuable important theme for various engineering fields. It is difficult to estimate an initials axial force of bolts, because the relationships between applied torque and initial axial force are changed and affected by both mechanical properties of materials between a bolts and the surface condition of bolts. In this study, in order to appropriate manage a torque of bolts in constructional materials bended by external forces, several bending tests for full-size box form roof used for underpass tunneling method are conducted. The results are demonstrated that as the torque of bolt is increased, both deflection and aperture are decreased. Furthermore, new evaluating method using FE analysis for this bending problem is developed.

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