大跨暗挖车站无柱中板结构内力分析及施工技术

Internal force analysis and construction technology of non-column structure of large-span underground excavation station

将大跨暗挖车站无柱中板结构总结为拱形支撑结构、平板斜撑结构和变截面厚板结构3类。采用Midas GTX软件,对3种无柱中板结构进行三维建模,并采用荷载结构法将3种结构形式的中板内力、跨中挠度、孔边梁受力情况进行数值分析。计算结果表明:拱形支撑结构与平板斜撑结构内力分布及结构变形基本相同,并小于变截面厚板结构;相同荷载条件下,拱形支撑结构内力分布最优,变截面厚板结构对站台层空间占用最小,结构内力及变形最大,对施工要求较高,平板斜撑结构形式简单,内力分布均衡,便于现场施工。拱形支撑结构及平板斜撑结构均已在青岛地铁1号线及6号线取得成功应用,为今后类似工程提供借鉴。

The medium plates of the large-span underground excavated column-free station had been categorized into arched support structure,plate diagonal structure and variable cross-section structure with thick plate.Three-dimensional modeling had been carried out on the medium plates of three types,using Midas GTX software.The load structure method had been used to numerically analyze the inner force of the medium plates,the mid-span deflection and the force on the side beam of hole.The calculation results showed that the internal force distribution and deformation of the arched support structure and the plate diagonal structure were basically the same and smaller than those of the variable crosssection structure with thick plate.Under the same load conditions,the internal force distribution of the arched support structure was the best;variable cross-section structure with thick plate occupied the smallest layer space of the station,but had the largest internal force and deformation,thus with high demand on construction.The plate diagonal structure was simple with reasonable internal force distribution,and was convenient for on-site construction.The arched support structure and the plate diagonal structure have been successfully applied in Qingdao Metro Line 1 and Line 6 projects,providing a useful reference for similar projects in the future.