为研究大断面矩形顶管法建造的装配式地铁车站的整体力学性能，依托深圳地铁12号线2期工程沙三站项目，参考车站的设计方案并结合有限元分析，设计车站建设过程中不同施工工况及正常使用工况下的1∶5缩尺模型，并根据不同工况下的受力情况开展模型试验，研究结构在各工况下的力学性能；通过逐步增加荷载，研究车站的承载能力极限，并将试验结果与有限元分析结果进行对比。试验结果表明： 1）在施工工况及正常使用工况下，结构基本处于弹性变形范围内，结构顶板虽然已有部分裂缝，但裂缝宽度小于0.2 mm，各部分内力及变形均满足规范要求。2）当静力荷载达到设计荷载的2.3倍时，结构的顶板、顶部托梁跨中出现了较多裂缝，结构发生大范围屈服，变形迅速增加，荷载-位移曲线出现拐点；当静力荷载达到设计荷载的2.5倍时，顶板支座出现斜裂缝，结构承载力达到极限。3）沙三站采用的结构形式合理，满足设计要求，具有较高的安全储备。4）二维有限元分析对体系转换后的结构适用性较差，需对模型进行校正或采取三维分析方法。
A case study is conducted on the Shasan station of the
Shenzhen metro line 12 Phase Ⅱ project to investigate the overall
mechanical performance of prefabricated rectangular metro stations with large
sections constructed using the pipe-jacking method. A
1:5 scale model of the station is developed to simulate various construction
and operational conditions based on the station′s
design scheme and finite element analysis. Model tests are performed to analyze
the structural mechanical behavior under different conditions. By incrementally
increasing the applied loads, the ultimate bearing capacity of the station is
assessed, and the experimental results are compared with those obtained through
finite element analysis. The test results are summarized as follows: (1) Under
construction and normal operating conditions, the station structure remains
primarily within the elastic deformation range. The maximum crack width on the
top slab is less than 0.2 mm, and the internal forces and deformations
throughout the structure meet the relevant design requirements. (2) When the
static load reaches 2.3 times the design load, extensive cracking appears on
the top slab and at the mid-span of the top supporting
beams, indicating widespread yielding, a sharp increase in deformation, and the
emergence of an inflection point on the load-displacement
curve. At 2.5 times the design load, diagonal cracks develope on the supports
of the top slab, signifying that the structure has reached its ultimate bearing
capacity. (3) The structural form adopted at the Shasan station demonstrates a
high safety margin and meets all design requirements. (4) The two-dimensional finite element analysis method shows poor applicability
for this structural form and should be revised or replaced with a three-dimensional analysis approach.
