十字斜交换乘车站基坑优化方案对比

天津市轨道交通6号线与8号线的换乘车站平面呈十字斜交状,两车站基坑深度较大且深度不同,支护方案复杂,施工风险较高,同时由于管线切改问题导致原有施工方案无法推进。针对该换乘车站提出水平斜撑、暗挖逆作法、预留土方三种优化方案,通过有限元模拟和理论分析相结合的方法对这些方案分别从结构安全、施工技术、施工工期三个方面进行了对比分析。结果表明:对于复杂异形斜交换乘车站,换乘节点采用水平斜撑方案会导致围护结构变形受力不均匀,渗漏风险高; 采用暗挖逆作法方案虽然结构受力简单,但施工难度较大,设备投入高,工期较长; 预留土方方案将换乘车站分为若干独立基坑,若合理统筹施工顺序,技术上更为安全可靠,工期更优; 研究成果可为其他复杂条件下斜交换乘车站施工方案的设计和选择提供借鉴,对促进重大轨道交通工程建设具有一定意义。

Comparison of foundation pit optimization schemes of cross oblique transfer station

The plane of the transfer station of Tianjin Rail Transit Line 6 and Line 8 is cross oblique. The depths of the foundation pit of the two stations are large and different, the support schemes are complex, the construction risk is high, and the original construction scheme cannot be promoted due to the problem of pipeline cutting. Aiming at the transfer station, three optimization schemes of horizontal bracing, reverse excavation and reserved earthwork were put forward. Through the combination of finite element simulation and theoretical analysis, these schemes were compared and analyzed from three aspects of structural safety, construction technology and construction period. The results show that for the complex special-shaped transfer station, the horizontal bracing scheme will lead to uneven deformation of the retaining structure and high risk of leakage. Although the structure by reverse excavation is simple, but the construction is difficult, equipment investment is high, and construction period is long. The reserved earthwork scheme divides the transfer station into several independent foundation pits. If the construction sequence is reasonably coordinated, it is technically safer and more reliable, and the construction period is better. The research results can provide reference for the design and selection of the construction scheme of oblique transfer station under other complex conditions, and have certain significance for promoting the construction of major rail transit projects.