地铁车站预留区间隧道下穿条件技术措施及风险控制

城市地铁发展迅速,交通体系日益复杂化,先行建造的地铁车站预留远期线路的区间隧道下穿问题日渐增多,基坑方案设计和施工控制面临新的挑战。为满足车站预留下穿的需要,并保证先建车站预留下穿范围段的围护安全,根据工程地质条件和设计要求,在上海轨道交通某车站主体穿越区范围采取了加长连续墙、使用玻璃纤维钢筋、桩基托换等在内的多项具体措施。在对这些方案措施进行评述的基础上,对现场监测发现的穿越段围护实际开挖变形异常增大的不利现象加以了说明,并就应急方案和风险成因进行了细致分析,总结提出了相关建议,为类似工程提供有益参考。

The city subway develops quickly and the transport system is becoming more complicated.To the subway station constructed antecedently,the technical problem of reserve tunnel underneath passing increases gradually.The conceptual design and construction control of foundation pits face many new challenges.In order to satisfy the demand of station reserve underneath passing,and ensure the safety of antecedent station pit bracing structure,many specific schemes are adopted in a subway station in Shanghai,according to the engineering geological conditions and the design requirement.The schemes including lengthening the continuous walls,using fiberglass reinforcement and piled foundation underpinning etc.are discussed.Furthermore,the abnormal and dangerous pit bracing deformation in the passing area is introduced.The emergency scheme and risk causation are analyzed in detail;suggestions are presented to give useful reference for similar projects.