中铁上海设计院集团有限公司

[Objective]Shanghai is the central city of the Yangtze River Delta integration,its Suburban Railway Demon-stration Zone Line(shorted as D Zone Line)plays a significant strategic role in promoting the integration of the Yangtze River Delta.In combination with the Jiangnan characteristics and functional requirements of D Zone Line in terms of historical development,cultural attributes,and geographical features,Xicen Station is taken as a case study,the dual-station integra-tion design and development strategy of D Zone Line Line sta-tion and the elevated subway station of Shanghai Metro Line 17 is introduced,aiming to provide a reference for the integration model of city railways and urban rail transit under the needs of the Yangtze River Delta integration.[Method]Several major challenges faced by the dual-station integration of Xicen Sta-tion,including engineering challenges,scale challenges,spa-tial challenges,and cognitive challenges,are analyzed.And by conducting demonstrations from three perspectives of archi-tecture,structural design,and interior design,the design re-sponse strategies to several major and difficult issues are ana-lyzed.[Result & Conclusion]Xicen Station integrates archi-tectural design thinking into the design strategy of infrastruc-ture.Through architectural controls(color,scale,space,modularity),structural deductions(large-span structures,structural phase and layering),and interior implementation(signage integration),it successfully defines a new paradigm for the highly integrated design of city railway stations and ur-ban rail transit facilities.This not only enhances the overall ef-ficiency of the integrated rail network but also provides passen-gers with a comfortable and convenient travel experience.

[Objective] The machinery construction method for link passages has been widely applied in 6-meter-class diameter shield tunnels, typically used in metro projects. However, there are few engineering practice cases and the limited research regarding its application in city railway tunnels, where 9-meter-class large-diameter shields are used. [Method] Focusing on a city railway project with 9-meter-class diameter shield tunnel, a three-dimensional load structure model of main tunnel and link passage is established. Under varying conditions of burial depth, soil parameter, and shield machine thrust, the impact of link passage construction on the main tunnel structure is analyzed from three aspects: deformation, axial force, and bending moment of special segments under different operating conditions. [Result & Conclusion] The additional deformation caused by the construction of link passage is influenced by both the burial depth and the thrust of the shield machine. When the burial depth is large, the link passage construction will increase the convergence deformation of the main tunnel; when the burial depth is small, it reduces the convergence deformation. An increase in shield machine thrust further reduces the convergence deformation of the main tunnel. Changes in the main tunnel internal forces are mainly concentrated in the steel segment sections of the three-ring special segments, where the axial force and bending moment at the arch waist of semi-open segment significantly increase, with the maximum occurring under operational conditions, which requires special attention during design. In contrast, internal force changes in the concrete segments are relatively minor.

In order to find out the horizontal axis offset law of the tube sheet caused by small curvature radius shield tunnel construction,and to prevent the occurrence of undesirable phenomena such as tube sheet misplaced breakage.Based on the modified longitudinal equivalent continuity model,the ellipticized deformation of tunnel convergence and the influence of comprehensive factors of curved tunnels are considered.By constructing the deflection differential equation of the Winkel foundation beam under the condition of small curvature radius,the prediction model of horizontal axis offset of the tube sheet in the construction stage of small curvature radius shield is established.The engineering applicability of the prediction model is verified by relying on the shield tunnel project of Nanchang City Railway Line 3.The results show that:when the tube sheet is assembled within 6 rings,the maximum error between the theoretical value of the prediction model and the monitoring and simulation values is 13.36%and 25.68%,respectively.The maximum errors between the theoretical values and the monitored and simulated values are 4.91%and 8.95%,respectively,when the pipe pieces are assembled in the range of 7 to 22 rings.The theoretical,simulated and monitored values of the tube sheet assembled in the 30th ring are-20.562 mm,-22.370 mm and-20.949 mm respectively,and the error between the theoretical and monitored values is less than 5%,and the overall trend is basically the same,which can effectively solve the problem of calculating the horizontal axial deviation of the tube sheet in the construction of shield tunnel under the condition of small radius of curvature.

[Objective] Public spaces serve as a vital carrier for user activities within rail transit station areas. To enhance spatial performance and quality vitality of these areas, it is necessary to analyze the distribution characteristics of public spaces and their influencing relationships. [Method] Focusing on public spaces within rail transit station areas in Shanghai core urban districts, 10 representative station areas are selected. Field surveys and variance analysis methods are employed to examine the typical spatial distribution characteristics of public spaces. Furthermore, from the perspective of user demands and through correlation analysis, the influencing relationships are preliminarily revealed, forming the basis for planning recommendations concerning public spaces in station areas. [Result & Conclusion] Square-type public spaces and privately-owned public spaces exhibit a pronounced concentric diminishing distribution pattern within station areas, while park-type public spaces show no clear concentric patterns. A relationship chain—'user demand-functional space distribution-public space distribution'—is proposed, in which user demands are the internal driving force behind the differentiation of public space in the station areas. For the future development and renewal of such public spaces, it is recommended to determine public space provision based on user demands, coordinate the distribution of public spaces with functional spaces, and promote systematization of public spaces through pedestrian linkages, thereby improving the spatial performance and quality vitality of station areas.

In order to improve the seismic resilience of steel truss moment frame systems,the concept of self-centering steel truss moment frame system is proposed.The study focuses on the strength reduction factor of self-centering steel truss moment frame systems under pulse-like ground motions.The behavior of steel truss moment frame system with trilinear hysteretic rules is well studied using an equivalent single-degree-of-freedom(ESDOF)system.Nonlinear dynamic analysis are conducted on the ESDOF system with various hysteretic parameter combinations under 182 pulse-like ground motions,resulting in a database containing 60.22 million strength reduction factors.The study explores the influences of different hysteretic parameters and pulse-like ground motions on the strength reduction factor.Furthermore,the parameters of the log-normal distribution models for the strength reduction factors under earthquakes are fitted using BP neural networks.A probability-based model for the strength reduction factor of the self-centering steel truss frame system is established.The results demonstrate the accuracy of the proposed model.