为完善台车结构设计理论，依托临滕高速方山隧道，通过数值模拟与现场实测分析二次衬砌台车在不同浇筑工况下的结构应力及模板变形，并对二次衬砌台车在不同浇筑工况下的应力分布特征及变化规律进行总结分析。结果表明： 1)浇筑过程中台车应力主要集中在拱脚千斤、门架结构及承重立柱上，应力值最大达585.8
MPa。在边墙非对称浇筑时模板变形最大位置位于拱顶，达10.97 mm。2)边墙浇筑时台车行走方向上两端立柱受拉而中心受压，拱顶浇筑后两端受压而中心受拉。外侧立柱在浇筑至横梁且存在高差时，两侧应力差值达到极值，位于台车行走方向中间的左侧立柱拉应力在浇筑至横梁高度时达到极值12.2 MPa，右侧压应力同样达到极值23.6 MPa。3)存在浇筑高差时左侧横梁受压而右侧横梁受拉，拱顶浇筑后横梁承受的压应力在台车行走方向上由两端向中心减小。以台车行走方向首端截面为例，边墙未浇筑至横梁高度时应力无明显变化，边墙浇筑至横梁高度时，左右横梁所受应力都从拉应力转压应力，左侧达19.2 MPa，右侧达4.4 MPa。
To improve the structural design theory of the
secondary lining trolley, numerical simulations and field measuring are
conducted to analyze the structural stress and formwork deformation of the
secondary lining trolley under various concrete pouring conditions, and the
stress distribution and variation patterns of the trolley are summarized by
taking the Fangshan tunnel of the Linyi-Tengzhou expressway as a
example. Results show that: (1) The trolley stress primarily concentrates on
arch springing jacks, portal frames, and load-bearing
columns, with a maximum reaching 585.8 MPa. The maximum formwork deformation occurs at the crown when
asymmetrically concreting at sidewalls, reaching 10.97 mm. (2) The end columns
tensioned and the central one compressed along the walking direction of the
trolley when concreting sidewalls, whereas the end columns compressed and the
central one tensioned after crown concreting. When the outer columns are
concreted to the crossbeam with a height difference, the stress difference
reaches an extreme. The left column′s tensile stress
reaches 12.2 MPa and the
right column′s compressive stress reaches 23.6 MPa. (3) When there is a concreting
height difference, the left compressed and the right tensioned. After crown
concreting, the compressive stress on the crossbeam decreases from both ends to
the center. Taking the front end section of trolley waking direction as an
example, the stress changes little when sidewalls have not yet been concreted
to the crossbeam height; when concreting to the crossbeam height, the stress on
both sides changes from tensile to compressive, with the left and right
reaching 19.2 MPa and 4.4 MPa, respectively.
