The three-hinge precast arch culvert consists of two segmental precast units and three hinge points.It harnesses the passive resistance of an embankment by permitting deflection,resulting in a mechanically stable stru...The three-hinge precast arch culvert consists of two segmental precast units and three hinge points.It harnesses the passive resistance of an embankment by permitting deflection,resulting in a mechanically stable structure.However,the design of the three-hinge precast arch culvert differs from that of a conventional culvert,prompting the mechanical behavior of the culvert to become an important issue.In this study,therefore,1/5 scale model tests were conducted on a three-hinge precast arch culvert to measure the changes in the inside width and earth pressure acting on the culvert at each step in order to investigate the culvert’s mechanical behavior at each construction stage.Moreover,the deflection measurement of the culvert was obtained at the in-situ construction site.The results indicate that the arch members were displaced according to the embankment depth in a similar manner to the design load.Therefore,the horizontal earth pressure,which was larger than the earth pressure at rest,acted on the culvert at the end of its construction.展开更多
Construction of urban tunnels requires the control of surface subsidence to minimize any disturbance to nearby buildings and services. Past study of surface subsidence has been limited to mainly empirical solutions ba...Construction of urban tunnels requires the control of surface subsidence to minimize any disturbance to nearby buildings and services. Past study of surface subsidence has been limited to mainly empirical solutions based on field studies, and very few analytical studies have been carried out. The available analytical solutions are not sufficient to include complex ground conditions; hence, a comprehensive analytical solution coupled with numerical modeling is necessary to model the effect of surface subsidence due to tunneling. This paper presents the results of modeling of surface settlements due to tunneling using the finite element method. The effect of the overconsolidation ratio of soils expressed in terms of the co- efficient of earth pressure at rest （K0） on surface subsidence due to tunneling is investigated. It is demonstrated that surface settlements appear to be sensitive to K0 values, and for geotechnical calculations pertaining to overconsolidated sand and clay soil, K0 values of 0.6 and 0.8, respectively, are proposed.展开更多
基金supported by the National Institute for Land and Infrastructure Management,MLIT,Japan(grant for the research and development of technologies for improving the quality of road policies,no.24-4,2012-2015).
文摘The three-hinge precast arch culvert consists of two segmental precast units and three hinge points.It harnesses the passive resistance of an embankment by permitting deflection,resulting in a mechanically stable structure.However,the design of the three-hinge precast arch culvert differs from that of a conventional culvert,prompting the mechanical behavior of the culvert to become an important issue.In this study,therefore,1/5 scale model tests were conducted on a three-hinge precast arch culvert to measure the changes in the inside width and earth pressure acting on the culvert at each step in order to investigate the culvert’s mechanical behavior at each construction stage.Moreover,the deflection measurement of the culvert was obtained at the in-situ construction site.The results indicate that the arch members were displaced according to the embankment depth in a similar manner to the design load.Therefore,the horizontal earth pressure,which was larger than the earth pressure at rest,acted on the culvert at the end of its construction.
文摘Construction of urban tunnels requires the control of surface subsidence to minimize any disturbance to nearby buildings and services. Past study of surface subsidence has been limited to mainly empirical solutions based on field studies, and very few analytical studies have been carried out. The available analytical solutions are not sufficient to include complex ground conditions; hence, a comprehensive analytical solution coupled with numerical modeling is necessary to model the effect of surface subsidence due to tunneling. This paper presents the results of modeling of surface settlements due to tunneling using the finite element method. The effect of the overconsolidation ratio of soils expressed in terms of the co- efficient of earth pressure at rest （K0） on surface subsidence due to tunneling is investigated. It is demonstrated that surface settlements appear to be sensitive to K0 values, and for geotechnical calculations pertaining to overconsolidated sand and clay soil, K0 values of 0.6 and 0.8, respectively, are proposed.
