软土地区盾构隧道穿越地下管线引起的管线沉降分析

Analysis on the Pipeline Settlement in Soft Ground Induced by Shield Tunneling across Buried Pipeline

盾构隧道施工引起地下管线沉降的规律与通常情况下盾构推进引起的地层沉降规律有明显的不同。基于某软土地区地铁隧道工程实例,对上、下行线隧道穿越地下煤气管线的整个施工期间及其后续阶段的管线沉降观测数据进行分析,从管线沉降随切口位置的变化、直接观测点与间接观测点的沉降比较、不同位置观测点的沉降比较和纵向沉降特征等4个方面进行研究。结果表明:上、下行线隧道引起地下管线的累计沉降历程规律基本一致;采用间接观测点观测地下管线沉降具有一定的合理性;上、下行线隧道引起地下管线上不同位置观测点沉降的规律有所差异;上行线穿越后,地下管线的纵向沉降近似符合Guassian正态分布,而下行线穿越后不再服从该分布形式。

The settlement law of buried pipeline in soft soil, which is caused by shield tunneling across buried pipeline, is obviously different from that of ground settlement induced by shield tunneling without buried pipelines. Based on certain metro tunnel engineering example in soft soil region, the observation data of pipeline settlement for tunnels of both up and down lines cross the gas pipes during construction and later stage were analyzed. R search was carried through in four aspects, including the pipeline settlement along with the change of cuthing positions, the comparison between the settlement of the direct observation point and that of indirect observation point, the comparisons of the settlement at different observation points, and the characteristics of the longitudinal settlement. The results showed that the accumulative settlement process induced by tunnels of both up and down lines basically agreed well. It was reasonable to observe the settlement of pipelines by adopting indirect observation point. There was obvious difference in the settlement law at different positions along the pipelines of the up and down line tunneling. The longitudinal settlement of the buried pipelines approximately matched with the Gaussian distribution after the up line tunneling. However, it no longer matched with the Gaussian distribution after the down line tunneling.