城市轨道交通地下区间大跨度疏散平台结构设计

疏散平台作为地铁区间的快速辅助逃生通道,在城市轨道交通领域具有十分重要的作用。北京新机场线采用7.6 m直径的大盾构隧道断面,造成疏散平台平面宽度较大;为了满足本工程施工进度的要求,设计方案中增大了疏散平台支撑间距。因此,需要重新进行结构受力分析,建立支撑结构及平台板有限元模型并进行仿真计算。研究表明,1.6 m跨度疏散平台的平台板和支撑型钢的最大变形分别为5.335 mm和1.1 mm,最大应力分别为2.9 MPa和57.2 MPa,均在容许值范围内,所采用的平台板复合材料、支撑型钢等结构的受力性能亦满足规范要求。大跨度疏散平台方案有利于减少施工现场平台板的数量,有效提高现场疏散平台拼装施工的效率。

Research on the Structural Design of Long-span Evacuation Platform in Underground Section of Urban Rail Transit

The design and use of evacuation platforms provides a quick exit for passengers in case of emergency.As the main escape way of subway,evacuation platform plays a very important role in Daxing airport line project.As a fast railway,the Beijing Airport Line has a large design value of the boundary,which results in a large plane width of the evacuation platform.The existing support structure design can not meet the structural stress deformation requirements,and the structural design needs to be re-designed.The system is mainly composed of walking board,handrail and its supporting parts.The evacuation platform system of Daxing airport line adopts the large-span structure.In this paper,the finite element model of supporting structure and platform plate is established and simulated.After calculation,the stress and deformation of steel structure,the deformation and bending moment of the platform plate of Daxing airport line are all within the allowable range,meeting the requirements of design and use.