The existing analytical models for umbrella arch method(UAM)based on elastic foundation beams often overlook the influence of the surrounding soil beyond the beam edges on the shear stresses acting on the beam.Consequ...The existing analytical models for umbrella arch method(UAM)based on elastic foundation beams often overlook the influence of the surrounding soil beyond the beam edges on the shear stresses acting on the beam.Consequently,such models fail to adequately reflect the continuity characteristics of soil deformation.Leveraging the Pasternak foundation-Euler beam model,this study considers the generalized shear force on the beam to account for the influence of soil outside the beam ends on the shear stress.An analytical model for the deformation and internal forces of finite-length beams subjected to arbitrary loads is derived based on the initial parameter method under various conditions.The mechanical model of the elastic foundation beam for advanced umbrella arch under typical tunnel excavation cycles is established,yielding analytical solutions for the longitudinal response of the umbrella arch.The reliability of the analytical model is verified with the existing test data.The improved model addresses anomalies in existing models,such as abnormal upward deformation in the loosened segment and maximum deflection occurring within the soil mass.Additionally,dimensionless characteristic parameters reflecting the relative stiffness between the umbrella arch structure and the foundation soil are proposed.Results indicate that the magnitude of soil characteristic parameters significantly influences the deformation and internal forces of the umbrella arch.Within common ranges of soil values,the maximum deformation and internal forces of the umbrella arch under semi-logarithmic coordinates exhibit nearly linear decay with decreasing soil characteristic parameters.The impact of tunnel excavation height on the stress of unsupported sections of the umbrella arch is minor,but it is more significant for umbrella arch buried within the soil mass.Conversely,the influence of tunnel excavation advance on the umbrella arch is opposite.展开更多
Beipanjiang Bridge is a long-span concrete arch bridges with stiffened skeleton(CABSS)in China.It has a fixed end arch with the span of 445 m and the rise of 100 m.To evaluate the rationality of the construction seque...Beipanjiang Bridge is a long-span concrete arch bridges with stiffened skeleton(CABSS)in China.It has a fixed end arch with the span of 445 m and the rise of 100 m.To evaluate the rationality of the construction sequence and the time-dependent behavior of CABSS,an experimental study of a model bridge was explored.But the measured displacement and stress ratios of arch rib between prototype and model bridge did not subject to linear similarity relation when the time-dependent behavior was considered.So,the three-dimensional finite element models were established,and verified by the measured data.Then,the displacements and stresses of the prototype and model were compared with each other,when the elastic analysis or coupling of temperature and shrinkage,creep effect was considered.Furthermore,a parametric study was studied.The results showed that when the temperature,shrinkage and creep effect of concrete are considered,the finite element analysis results of prototype and model agree well with the measured results.The displacement and stress ratios of prototype and model bridge in construction and bridge completed stage do not present the geometric similarity ratio 7.5 and 1.0,respectively.They are also much influenced by concrete predicting model and variation of temperature.展开更多
连续刚构拱组合铁路桥是一种具有复杂结构形式和施工工序繁多的桥梁类型。为实现对该类型桥梁施工过程的全面监控和管理,以目前在建最大跨径无砟轨道高墩大跨连续刚构拱组合体系桥为背景,阐述BIM技术在该领域取得的研究成果,通过BIM技...连续刚构拱组合铁路桥是一种具有复杂结构形式和施工工序繁多的桥梁类型。为实现对该类型桥梁施工过程的全面监控和管理,以目前在建最大跨径无砟轨道高墩大跨连续刚构拱组合体系桥为背景,阐述BIM技术在该领域取得的研究成果,通过BIM技术对连续刚构拱组合梁桥进行参数化建模、施工动态模拟,以Visual Studio 2022作为开发平台开发了线形与应力监控系统,系统包含数据管理、测点设计、接口设计、模型应用等四大功能模块,对施工监控数据进行有效管理。研究结果表明:采用基于BIM数据驱动的参数化建模技术,提高了建模效率和准确性。桥梁线形数据的可视化表达简化了监控数据与设计值的对比工作,可视化模拟施工工况和动态预警提示功能为桥梁线形的发展规律分析提供参考。实现了监测数据与桥梁BIM模型的关联,方便数据存储和查找,同时可以直观地比较实测值与理论值的误差是否超限,简化了监测数据统计和对比工作。该软件系统为铁路桥梁工程的设计、施工和监测提供有力支持。展开更多
基金Projects(52008403,52378421)supported by the National Natural Science Foundation of ChinaProject(2022-Key-10)supported by the Science and Technology Research and Development Program Project of China Railway Group LimitedProject(202207)supported by the Hunan Provincial Transportation Science and Technology,China。
文摘The existing analytical models for umbrella arch method(UAM)based on elastic foundation beams often overlook the influence of the surrounding soil beyond the beam edges on the shear stresses acting on the beam.Consequently,such models fail to adequately reflect the continuity characteristics of soil deformation.Leveraging the Pasternak foundation-Euler beam model,this study considers the generalized shear force on the beam to account for the influence of soil outside the beam ends on the shear stress.An analytical model for the deformation and internal forces of finite-length beams subjected to arbitrary loads is derived based on the initial parameter method under various conditions.The mechanical model of the elastic foundation beam for advanced umbrella arch under typical tunnel excavation cycles is established,yielding analytical solutions for the longitudinal response of the umbrella arch.The reliability of the analytical model is verified with the existing test data.The improved model addresses anomalies in existing models,such as abnormal upward deformation in the loosened segment and maximum deflection occurring within the soil mass.Additionally,dimensionless characteristic parameters reflecting the relative stiffness between the umbrella arch structure and the foundation soil are proposed.Results indicate that the magnitude of soil characteristic parameters significantly influences the deformation and internal forces of the umbrella arch.Within common ranges of soil values,the maximum deformation and internal forces of the umbrella arch under semi-logarithmic coordinates exhibit nearly linear decay with decreasing soil characteristic parameters.The impact of tunnel excavation height on the stress of unsupported sections of the umbrella arch is minor,but it is more significant for umbrella arch buried within the soil mass.Conversely,the influence of tunnel excavation advance on the umbrella arch is opposite.
基金Projects(20-JKKJ-17,18-JKKJ-05)supported by the Shanxi Communications Holding Group Co.,Ltd.,ChinaProject(41907239)supported by the National Natural Science Foundation of China+1 种基金Project(2020M670698)supported by the China Postdoctoral Science FoundationProject(2019L0295)supported by the Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi,China。
文摘Beipanjiang Bridge is a long-span concrete arch bridges with stiffened skeleton(CABSS)in China.It has a fixed end arch with the span of 445 m and the rise of 100 m.To evaluate the rationality of the construction sequence and the time-dependent behavior of CABSS,an experimental study of a model bridge was explored.But the measured displacement and stress ratios of arch rib between prototype and model bridge did not subject to linear similarity relation when the time-dependent behavior was considered.So,the three-dimensional finite element models were established,and verified by the measured data.Then,the displacements and stresses of the prototype and model were compared with each other,when the elastic analysis or coupling of temperature and shrinkage,creep effect was considered.Furthermore,a parametric study was studied.The results showed that when the temperature,shrinkage and creep effect of concrete are considered,the finite element analysis results of prototype and model agree well with the measured results.The displacement and stress ratios of prototype and model bridge in construction and bridge completed stage do not present the geometric similarity ratio 7.5 and 1.0,respectively.They are also much influenced by concrete predicting model and variation of temperature.
文摘连续刚构拱组合铁路桥是一种具有复杂结构形式和施工工序繁多的桥梁类型。为实现对该类型桥梁施工过程的全面监控和管理,以目前在建最大跨径无砟轨道高墩大跨连续刚构拱组合体系桥为背景,阐述BIM技术在该领域取得的研究成果,通过BIM技术对连续刚构拱组合梁桥进行参数化建模、施工动态模拟,以Visual Studio 2022作为开发平台开发了线形与应力监控系统,系统包含数据管理、测点设计、接口设计、模型应用等四大功能模块,对施工监控数据进行有效管理。研究结果表明:采用基于BIM数据驱动的参数化建模技术,提高了建模效率和准确性。桥梁线形数据的可视化表达简化了监控数据与设计值的对比工作,可视化模拟施工工况和动态预警提示功能为桥梁线形的发展规律分析提供参考。实现了监测数据与桥梁BIM模型的关联,方便数据存储和查找,同时可以直观地比较实测值与理论值的误差是否超限,简化了监测数据统计和对比工作。该软件系统为铁路桥梁工程的设计、施工和监测提供有力支持。
