地铁基坑下穿铁路桥的桥墩保护设计方案合理性研究

Rationality Study on Pier Protection and Design Scheme of Metro Foundation Pit Under-crossing Railway Bridge

以深圳地铁12号线和平站下穿穗莞深城际铁路特大桥工程为依托,通过数值模拟和理论分析,对地铁基坑下穿段实施的桥墩保护措施的合理性展开了深入研究。研究结果发现:针对桥墩水平位移,若仅采用隔离桩和采用土体加固两个措施,对两侧桥墩产生的影响差别较小;设置隔离桩可有效控制桥墩的竖向位移;在地下连续墙能保证基坑稳定的前提下,改变其墙厚和嵌固深度,对桥墩位移的变化影响较小;分区开挖可有效控制基坑变形及临近桥梁区域土体的变形。

Based on the project of Shenzhen Metro Line 12 Heping Station under-crossing Guangzhou-Shenzhen Intercity Railway mega bridge,in-depth research and analysis on the rationality of bridge protection measures adopted in the metro foundation pit under-crossing section is carried out through numerical simulation and theoretical analysis.Research results show that:in terms of bridge pier horizontal displacement,adopting only isolation piles or only soil reinforcement causes slightly different effects on bridge pier on both sides;adopting isolation pile can effectively control the vertical displacement of bridge pier;when the diaphragm wall can ensure the stability of foundation pit,changing wall thickness and embedded depth has limited effect on bridge pier displacement;divisional excavation can effectively control the deformation of foundation pit and the deformation of soil in adjacent bridge area.