地铁深基坑施工对周边管线影响数值分析

Numerical analysis on the influence of deep metro excavation construction on adjacent pipelines

以厦门地铁一号线某深基坑的实测资料为基础,采用考虑土体小应变刚度特性的有限元方法,对基坑施工对邻近管线影响规律进行参数分析;结合规范中的变形控制标准,划分了基坑开挖对邻近管线影响分区。研究结果表明:相比于管线距基坑的水平距离,管线埋深对最大沉降量的影响更大;管线最大变形与坑外地层变形有较大的相关性,管-土之间的刚度对土体位移的限制作用有限;管线轴力随其距基坑的水平距离的减小而有所增大;管线轴线刚度越大,截面积越大,产生的轴力也越大。综合考虑基坑外管线的水平距离和埋深,基坑开挖对邻近管线的影响可划分为主要影响区(Ⅰ)、次要影响区(Ⅱ)、一般影响区(Ⅲ)和微弱影响区(Ⅳ)。

The deep metro excavation will lead to the deformation of adjacent pipelines.Knowing the influence of excavation construction on pipelines has significant meanings for controlling the deformation of pipelines effectively and reducing construction risks.Based on the actual measurement data of some excavation of Xiamen line1,parametric analysis is applied to the influence of excavation on adjacent pipelines by using the finite element method with the consideration of soil small strain stiffness characteristics.The influential zone of adjacent pipelines is divided combined with control standards on deformation.The study shows that burial depth of pipelines,compared to the horizontal distance of which from excavation,has a larger influence to the maximum settlement of pipelines.The maximum deformation of pipelines has considerable correlation to stratum deformation outside the excavation.The stiffness between pipeline and soil has limited restrictions to the soil displacement.The axial force will increase as the horizon distance from excavation declines.The larger axis stiffness and sectional area are,the bigger the axial force is.With overall consideration of pipelines horizontal distance,burial depth and other factors,the influence of excavation on adjacent pipelines can be divided into main influence area(Ⅰ),minor influence area(Ⅱ),general influence area(Ⅲ)and weak influence area(Ⅳ).