类矩形盾构隧道开挖引起邻近地下管线变形研究

Research on deformation of adjacent underground pipelines caused by excavation of quasi-rectangular shields

盾构隧道开挖环境影响的既有成果针对圆形盾构隧道施工效应做了较多研究,但针对类矩形盾构隧道施工效应的研究还较少。基于类矩形盾构隧道开挖面收敛位移变形模式,首先采用镜像法,提出类矩形盾构隧道施工诱发周围土体自由场位移的分析方法;其次,基于Winkler地基模型,将土体自由位移场施加于地下管线结构,提出类矩形盾构隧道施工诱发邻近管线变形的简化计算方法。通过工程实例分析,将土体自由场变形与实测数据进行对比验证;同时,采用有限元数值模拟方法,将管线竖向变形计算结果与本文简化方法进行对比分析。此外,针对隧道矩形长边宽度、隧道和管线埋深、管线直径、管线弹性模量、土体压缩模量、土体损失间隙参数等关键参数进行了影响分析。研究结果表明,采用类矩形盾构开挖面整体下沉收敛模式,镜像法解答得到的土体自由场位移与实测值吻合较好;提出的简化方法计算邻近既有管线变形的理论计算值与数值模拟值吻合较好。通过参数分析,可知隧道矩形长边宽度、管线埋深和管线弹性模量为敏感性参数。随着盾构矩形长边宽度的增大,管线变形曲线槽宽度显著增大;随着管线埋深的增加,管线变形显著增大;随着管线弹性模量的增大,管线变形显著减小。

Lots of research results of the impact of circular shield tunnel construction have been obtained,but there are few studies on the impact of quasi-rectangular shield tunnel construction.Based on the convergent deformation mode of the excavation face of the quasi-rectangular shield tunnel,an analysis method of the free field displacement of the surrounding soil around the quasi-rectangular shield tunnel was proposed by the mirror method,and a simplified calculation method of the deformation of adjacent pipelines induced by quasi-rectangular shield tunnel excavation was proposed based on the Winkler foundation model and by applying the free displacement field of the soil to the underground pipeline structure.Through the analysis of engineering examples,the free field deformation of the soil was compared with the measured data.At the same time,the finite element numerical simulation method was used to compare the calculation results of the vertical deformation of the pipeline with the simplified method.In addition,the key parameters of the long side width of the tunnel,the depths of the tunnel and the pipeline,the diameter of the pipeline,the elastic modulus of the pipeline,the compressive modulus of the soil and soil loss parameter were analyzed.The results show that the free field displacements calculated by the mirror method adopting the global free field settlement model of the quasi-rectangular shield excavation face are consistent with the measured values and that the theoretical calculations of the adjacent pipeline deformation by the simplified method are in good agreement with the numerical simulation results.Parameter analysis indicates that the pipeline deformation is sensitive to the long side width of the tunnel rectangle,the buried depth and the elastic modulus of the pipeline.The groove width of the pipeline deformation curve increases significantly with increasing the width of the long side of the shield rectangle,and the pipeline deformation respectively increases and decreases significantly with increasing the pipeline depth and the elastic modulus of the pipeline.