Recently, attention is drawn on elimination of secondary lining as one of the cost reducing theme for shield tunneling works. The authors have developed a segment system which is adaptable in eliminating secondary lining for small sized and mid sized shield tunnels. This segment system is based on segment pieces built from four reinforced concrete sections. By adopting a simplified joint system and optimization of joint locations, cost down as well as smoothness of internal surface and improvement in durability have been achieved. In addition, a mockup loading test was carried out to verify the soundness of the design approach of segments.

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A curved bolt is an economical system and being adopted commonly to joint R. C. segmental linings of a shield tunnel. On the other hand, these days higher performance for seismic resistance of a shield tunnel structure is getting requined in the basis at the Kobe Earthquaque experience, and especially the deformational character of the long longitudinal joint is very important factor to improve the matter. However, the aseismicity of the curved bolt joint have not been studied well, and capacity. Then in this paper, the tensile stiffness of the curved joint was examined by the analysis and the actual scale loading test. Furthermore, water-tightness of the hydro-swelling seal was also experimented for the large lipping by earthquaque.

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In resent years, new concepts of tunnel lining methods are suggested by the domestic contractors and the manufacturers in order to reduce the construction cost by simplifying the lining joints, the secondary lining omission e. g. The authors have developed the Prestressed Precast Concrete Segmental Lining for shield tunnels featured by the prestress introduction to the radial and circumferential lining direction. This paper reports the summary, the technical feature, the construction procedure, and the site monitoring results to develop the feasibility of PPCSL application to the construction market.

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It is difficult to install the effective stress meter or strain gage for ECL (Extruded Concrete Lining) method with the continuous concrete placing compared with the case of the conventional concrete lining. The strain releasing method has been firstly introduced to the stress measurements in ECL and authors discuss about the corresponding results. The three-axis rosette gauge is installed on the surface of concrete and acting stresses are released through cutting of its surrounding. The major and minior principal stresses are evaluated based upon the measured strains.

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We have developed RC segments (called “Simple Process Segment”) which have new type structural joints. Simple Process Segment has a feature that joints are prepared inside the segment part and aren't exposed in the superficies out of the segment. For longitudinal joint, we adopt coupler which can be concluded only inserted in the direction of the tunnel axis.
We report on the examination result which was implemented to grasp the dynamics characteristic of coupler when using it as longitudinal joint.

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The applicability of Seismic Deformation Method (S. D. M) for multi layer cut-and-cover tunnel has been examined by comparing the results among FEM S. D. M, frame S. D. M and 2-D dynamic analysis (FLUSH). Because setting of spring coefficients is important as for the frame S. D. M, the influence of spring coefficients has been examined. As a result it is indentified that if the spring coefficients can be evaluated adequately, the frame S. D. M is able to be applied to seismic design even though the height of structure changed. And, from the sensitive analysis of spring coefficients it is understood that the effects on the results due to the horizontal springs (shear spring of top/bottom slab, normal direction spring of side wall) are great, but when the height of structure increased the effects by all spring coefficients become small. In the other way, the results with good precision can been obtained by using FEM S. D. M even if the height of structure changed.

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A pseudo-structure with a layer and two spans containing center pillars is often used at and between subways stations. Open cut tunnels are normally designed based on the twodimensional frame analysis of the cross section that contains a center pillar. We performed three-dimensional analysis of a model that precisely simulates the tunnel structure in case of a serviceability limit state and during an earthquake. Based on the results of analysis, we studied a method to appropriately reflect the three dimensional effects in the two-dimensional frame analysis.

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Concrete-filled tubular steel columns are generally used as center piles in underground rail station constructed by open cut method. However, as underground rail stations tend to be constructed at deeper place below the ground, the axial force over the column tends to increase, and due to the increase of steel pipe thickness and a size of bearing plate cost becomes a problem. Therefore, to lower costs, we suggest a new type concrete-filled tubular steel column.
This article reports that the result of specimen loading test at a reduction model to confirm a validity of an investigation and suggestion by analysis. Also according to the results of the test we will suggest a method of design of concrete-filled steel columns.

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While many long and curved tunnels by jacking method are constructed in recent years, there are few examples that measured behavior of Hume pipes. Calculation of driving forth by jacking method is not established completely, because it is complicated by various soil and execution methods. Therefore designers cannot help judging by experience expressions from past results. This report describes that we measured stress and examined behavior of Hume pipes for the purpose of collecting data to establish reasonable design technique about jacking method.

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