跨座式单轨新型路基结构动力响应特性研究

Dynamic Response Characteristics of New Subgrade Structure of Straddle-Type Monorail Train

跨座式单轨交通自21世纪初引进我国以来发展迅猛,对改善城市交通现状的发展潜力不容忽视。现有的研究主要着重于动力学和轨道结构设计优化等方面,鲜有对其下部结构的研究。从挖方段、桥隧过渡段、车场等特殊路段出发,结合目前主流的高速铁路和下埋式轻轨交通的路基结构,提出符合这些特殊路段的跨座式单轨新型路基结构形式,并利用ADINA有限元数值模拟软件建立有限元模型,设计了考虑6个主要影响因素的正交试验,对跨座式单轨新型路基结构力学特性的影响因素进行了敏感性分析,依据轨道梁竖向位移、基床表层竖向位移、基床表层有效应力和地基有效应力4个评价指标获取了跨座式单轨新型路基结构设计的最优方案。结果表明:6个影响因素对跨座式单轨新型路基结构优化设计表现出不同的敏感性,其中地基弹性模量对新型路基结构优化设计最为敏感,基床厚度、轨道板等也在不同的评价指标下对新型路基结构优化设计的影响程度排名靠前;该新型路基结构的最优设计方案为:基床厚度为1.4 m,基床表层弹性模量为140 MPa,基床底层弹性模量为90 MPa,轨道板为C55,支承层为C15。

The straddle-type monorail transportation has developed rapidly since it was introduced into China at the beginning of the 21st century,and its development potential cannot be ignored in light of the current urban traffic situation.However,domestic and foreign scholars have mainly studied their dynamics and track structure design optimization,and few scholars have studied their substructures.This paper starts with special sections such as excavation section,bridge and tunnel transition section and parking lots,stu-dies the current subgrade structure of high-speed railway and underground light-rail transit,and proposes a new subgrade structure of straddle-type monorail train that conforms to these special sections.Then,the paper establishes the corresponding models using the ADINA which is a finite element numerical simulation software.Later,considering the six main influencing factors and combined with orthogonal test me-thods,the paper conducts sensitivity analysis on the influencing factors of mechanical properties of the new subgrade of straddle-type monorail train,and obtains the optimal design of the new subgrade structure design based on four evaluations of the vertical displacement of the track beam,the deformation of the top surface of the bed,the effective stress on the surface of the bed and the effective stress on the foundation.In the design process of the new subgrade of the straddle-type monorail train,the elastic modulus of the foundation is the most sensitive amongthe six influencing factors considered.The thickness of the bed and the sensitivity of the elastic modulus of the track slab have high impact ranking under different evaluation indicators.The paper attempts preliminary optimization design of straddling monorail subgrade and discu-sses the dynamic response of the new subgrade structure under different foundation conditions.The stra-ddle-type monorail subgrade structure studied not only meets the design requirements of the code,but also provides reference for the lack of the subgrade part of the code,and plays a positive role in the promotion and application of straddle-type monorail traffic.