正常固结土层盾构隧道开挖对既有桥梁桩基的影响

Influence of Shield Tunnel Excavation on Existing Bridge Pile Foundation in Normally Consolidated Soil

研究了正常固结土中盾构施工对桩基的影响。将土体损失率与有限元模型相结合,建立了12个模型,分析了不同土体参数、损失率、不同埋深以及不同隧道开挖边界距离下土体的水平位移变形规律,并通过不同位置深度位移与隧道径向压缩量的关系,建立了盾构施工引发土体位移的预测模型。该模型弥补了常用的Winkler弹性地基梁模型未考虑地基土体抗剪作用以及空间效应的缺陷。此外,结合预测模型建立了简化地基梁模型,通过与理论分析数据以及实际工程数据对比,验证了模型的有效性,可为盾构临近桥梁桩基施工分析计算提供简便算法,为桩基保护措施的采取提供依据。

In this paper,the impact of shield construction on deep foundation in normally consolidated soil has been studied,the law of horizontal displacement and deformation of soil under different soil parameters,loss rate,different buried depth and different distance of tunnel excavation boundary has been studied and analyzed,based on the relationship between the depth displacement at different positions and the radial compression of the tunnel,the prediction model of soil displacement induced by shield tunneling has been established,this model makes up the defect that the usual Winkler elastic foundation beam model does not consider the shear resistance and spatial effect of foundation soil.In addition,a simplified foundation beam model has been established based on the prediction model,and the validity of the model is verified by comparing with the theoretical analysis data and the actual engineering data,it can provide a simple calculation method for the analysis and calculation of the pile foundation construction of the bridge adjacent to the shield machine,and provide a basis for the adoption of pile foundation protection measures.