双线盾构隧道连续下穿老旧建筑群施工技术

Construction Technologies of Double-line Shield Tunnel Passing Underneath Old Buildings

盾构下穿老旧建筑群,具有施工难度大、风险高等特点,施工前可结合工程特点进行相应的数值模拟分析,并提出针对性的应对措施。结合昆明地铁某双线盾构区间连续下穿老旧建筑群工程特点,基于三维有限差分软件FLAC3D建立计算模型,对双线盾构开挖、支护等主要工序进行分析模拟,总结并提出了掘进关键参数,并在八大处空地模拟穿越三角大院试验段得以成功应用。由于地层的不确定性,盾构施工参数需要发生相应的变化,根据地表沉降的走向和趋势及时动态地调整施工参数尤为必要。工程实践证明,基于数值分析结果及试验段总结的施工参数,通过对掘进参数不断优化处理,有效确保了盾构下穿昆枢指挥部、铁路工程管理所等老旧建筑群时的高效性和安全性,为昆明地铁及类似工程施工提供了经验及依据。

Shield driving under old buildings has high construction difficulty and is high risky.Based on engineering features,numerical simulation and analysis should be carried out before construction and targeted measures should be put forward.A shield section for a subway in Kunming which continuous pass underneath old buildings is used as the study object,calculation model is established based on the software FLAC3D,and the main work process such as shield excavation for both lines and tunnel support are simulated and analyzed.Key parameters for driving are put forward and are successfully applied to eight test sections where shield tunnel passes through triangle compound.Due to the formation uncertainty,shield construction parameters should be adjusted timely,especially the construction parameters should be timely and dynamically adjusted according to the changes in surface subsidence and trend.Based on the numerical analysis results and test section construction parameters,tunneling parameters are optimized continuously,which has effectively guaranteed high efficiency and safety for shield construction under old buildings,which can provide experience and basis for construction of subway and similar projects in Kuming.