近接运营线路超长深基坑分坑施工方案比选研究

依托福州滨海快线火车站基坑工程，制定两套近接运营线超长深基坑的分坑施工方案，采用FLAC3D软件对分坑施工全过程进行数值模拟，重点关注围护结构与近接运营线的水平位移变化规律。分析结果表明：两套分坑施工方案的围护结构水平位移分布规律大致相同，均呈上部小、中部大的“鼓包”状；两套分坑施工方案的运营线水平位移分布规律也大致相同，一期开挖使运营线呈现出4处“局部凸出”形态，二期开挖则使其水平位移整体增大。

Study on Comparison on the Separating Construction Scheme of Extra-long Deep Foundation Pit Adjacent to Operating Line

Based on the foundation pit project of Railway Station of Fuzhou Binhai Express Line, two separating scheme are proposed for the construction of extra-long deep foundation pit adjacent to the operating line. The construction processes of two separating schemes are simulated by the FLAC3D software, and the horizontal displacement change law of retaining structure and adjacent operating line are well focused. The analysis results show that the horizontal displacement distribution law of retaining structure is similar in both two separating scheme, showing a "bulge" shape with small upper part and large middle part. The horizontal displacement distribution law of the operating line is also similar in both two separating scheme. The operating line presents four "local protrusions" after the first phase of excavation and then its horizontal displacement increases overall after the second phase of excavation.