大断面双孔矩形顶管下穿高速公路深层土体竖向应力分析

Vertical Stress Analysis of Deep Soil Mass of Large Section Double Hole Rectangular Pipe Jacking Under Expressway

结合北京某综合管廊下穿高速公路工程实际,采用Abaqus有限元软件建立了高速公路和矩形顶管的三维模型,计算了9.1m×5.5m顶管和7.0m×5.0m顶管先后下穿高速公路情况下的顶管上方土体竖向应力,并分析了并行顶管的相互影响。计算结果表明:土体竖向应力变化明显区域主要集中在顶管上方1.5 H(H指顶管断面高度)土体范围,顶管上方土体竖向应力沿顶管纵轴线方向均呈现先小幅增大、后急剧减小的变化规律,应力曲线呈倒马鞍形分布形态;并行顶管间距较小,受后行顶管7.0m×5.0m顶进施工影响,先行顶管9.1 m×5.5 m管节上方土体竖向应力最大值增加了4%。

Vertical stress analysis of deep soil mass of large section double hole rectangular pipe jacking underpass Expressway combined with the actual project of Underpass expressway of a comprehensive pipe gallery in Beijing,the three-dimensional models of Expressway and rectangular pipe jacking are established by using ABAQUS finite element software,calculation 9.1m×5.5m rectangular pipe jacking and 7.0m×5.0m pipe jacking successively crosses the expressway,and the interaction of parallel pipe jacking is analyzed.The calculation results show that the obvious change area of soil vertical stress is mainly concentrated in the range of soil 1.5h above the pipe jacking(H refers to the height of pipe jacking section).The vertical stress of soil above the pipe jacking first increases slightly and then decreases sharply along the longitudinal axis of pipe jacking,and the stress curve is in the shape of inverted saddle.The distance between parallel pipe jacking is small,affected by the backward 7.0m×5.0m pipe jacking construction,,the maximum vertical stress of the soil above the 9.1m×5.5m pipe jacking joint is increased by 4%.