盾构施工引起的管线变形规律及安全风险评估

Pipeline deformation laws and safety risk assessments caused by shield construction

鉴于隧道施工会造成市政管线破坏,运用FLAC3D数值软件对盾构隧道上方管线进行模拟。通过在管壁上布置监测点,对管线进行施工过程沉降分析和最终沉降分析,并参考管线控制标准进行安全风险评估。研究结果表明:盾构面推进过程中,平行管线各点先后产生沉降且稳定后的最终沉降大致相同,正交管线各点会同时产生沉降,但稳定后的最终沉降有明显差异。管线沉降会先后经历盾构面前方变形期、盾构开挖扰动期和固结沉降期,超过75%的沉降发生于第二时期,且此时期沉降速率最大。随着管线侧向距离的增大,管线沉降不再符合埋深越大,沉降越大的规律,通过Gauss公式拟合能够计算得到管线最大沉降曲线。盾构施工对平行管线的破坏范围明显大于正交管线。

Tunnel construction will cause damage to municipal pipelines.This paper uses FLAC3D numerical software to simulate the pipeline above the shield tunnel.By arranging monitoring points on the pipe wall,this paper carries out settlement analysis and final settlement analysis of the pipeline during construction,which also refers to pipeline control standards for safety risk assessment.The research results show that during the advancement of the shield plane,the points of the parallel pipelines have successively settled,and the final settlements after stabilization are approximately the same.The points of the orthogonal pipelines settle at the same time,but the final settlements after stabilization are significantly different.The settlement of the pipeline will undergo the deformation period in front of the shield face,the disturbance period of the shield excavation,and the consolidation settlement period.More than 75%of the settlement occurs in the second period,and the settlement rate is the largest in this period.With the increase of the lateral distance of the pipeline,the settlement of the pipeline no longer conforms to the law of greater burial depth and greater settlement.The maximum settlement curve of the pipeline can be calculated by Gauss formula fitting.The damage scope of shield construction to parallel pipelines is significantly larger than that of orthogonal pipelines.