浅埋矩形顶管施工引起的地层沉降变化规律

Variation Law of Ground Subsidence Induced by Shallow-buried Rectangular Pipe Jacking Construction

以苏州轨道交通5号线某车站过街通道工程为例,应用现场监测及对比分析的方法,研究城市浅埋矩形顶管施工造成的地表沉降变化规律。研究结果表明:浅埋式矩形顶管顶进过程中地表变形经历了微扰动沉降、迅速沉降、注浆抬升、固结沉降四个阶段;顶管施工沿顶管轴线方向引起土体沉降的范围大致为距掘进面7.5 m以内区域;顶管施工造成的地表沉降范围横向宽度大致为顶管截面宽度的3倍。将现有理论预测公式与实测数据对比,结果表明:Peck公式以及随机介质理论均可用于预测浅埋矩形顶管施工造成的地表沉降。对既有案例进行对比统计,通过量纲一化分析得到沉降槽分布规律。

Taking the engineering of a station underground passageway of Suzhou Rail Transit Line 5 as example,by adopting site monitoring and comparative analysis methods,the variation law of ground subsidence induced by urban shallow-buried rectangular pipe jacking construction is studied.Results show that during the shallow-buried rectangular pipe jacking process,the ground surface deformation consecutively undergoes four phases:slight disturbance and subsidence,dramatic subsidence,grouting uplift and consolidation subsidence.In the direction along pipe jacking axis,ground subsidence is observed in an area within 7.5 m around the excavation face.Pipe jacking construction causes the ground subsidence width to be about three times of the pipe section width.By comparing existing theoretical prediction formula and in-situ monitoring data,results show that both Peck formula and stochastic medium model can be used to predict the ground subsidence induced by shallow-buried rectangular jacked tunnels.By comparative statistics of existing cases,the subsidence trough distribution patterns are concluded with normalization analysis.