豆红强, 王浩, 吴福宝, 席人双. 2018: 带多阳角的综合管廊垂直交叉节点深基坑的坑角效应分析. 工程地质学报, 26(6): 1657-1665. DOI: 10.13544/j.cnki.jeg.2017-473
    引用本文: 豆红强, 王浩, 吴福宝, 席人双. 2018: 带多阳角的综合管廊垂直交叉节点深基坑的坑角效应分析. 工程地质学报, 26(6): 1657-1665. DOI: 10.13544/j.cnki.jeg.2017-473
    DOU Hongqiang, WANG Hao, WU Fubao, XI Renshuang. 2018: CORNER EFFECTS OF DEEP EXCAVATIONS WITH MULTI EXPOSED CORNERS IN SQUARE CROSSING OF UTILITY TUNNEL. JOURNAL OF ENGINEERING GEOLOGY, 26(6): 1657-1665. DOI: 10.13544/j.cnki.jeg.2017-473
    Citation: DOU Hongqiang, WANG Hao, WU Fubao, XI Renshuang. 2018: CORNER EFFECTS OF DEEP EXCAVATIONS WITH MULTI EXPOSED CORNERS IN SQUARE CROSSING OF UTILITY TUNNEL. JOURNAL OF ENGINEERING GEOLOGY, 26(6): 1657-1665. DOI: 10.13544/j.cnki.jeg.2017-473

    带多阳角的综合管廊垂直交叉节点深基坑的坑角效应分析

    CORNER EFFECTS OF DEEP EXCAVATIONS WITH MULTI EXPOSED CORNERS IN SQUARE CROSSING OF UTILITY TUNNEL

    • 摘要: 坑角效应是基坑空间效应的重要体现形式之一,但目前对带多阳角深基坑的坑角效应还缺乏具体且深入的研究。以海南滨海软土地区两垂直相交的综合管廊狭长深基坑工程为依托,利用Plaxis 3D建立了两种典型施工模式下带多阳角的综合管廊交叉节点深基坑开挖的三维数值模型,对由开挖引起的地表沉降、支护结构变形以及支撑轴力等开展了细致的对比分析,并着重探讨了坑角效应对其分布形态的影响。计算结果表明:在两种典型施工模式下,综合管廊狭长深基坑的地表最大沉降变化区间约为0.11%He~0.67%He,且支护结构的最大侧向变形与开挖深度之间的上下限值分别为0.25% He、1.35%He。整体而言,在完全对称的施工模式Ⅱ下,基坑周围土体的地表最大沉降和支护结构的侧向变形均低于施工模式Ⅰ的计算结果;但在施工模式Ⅱ下,基坑开挖过程中在阳角的两个临空面方向均表现为显著的坑角效应,而在施工模式Ⅰ下,仅在阳角形成之后的单一方向上表现为明显的坑角效应。坑角效应的影响范围约为2倍的开挖深度,在坑角效应的影响范围内,基坑周围土体的地表沉降、支护结构的侧向变形以及支撑轴力均较坑角效应影响范围以外的计算结果显著降低。研究认为,若在带多阳角的综合管廊交叉节点处的深基坑设计中合理考虑坑角效应的影响范围及其发挥程度,可在一定程度上降低工程成本。

       

      Abstract: The corner effect is one of the important forms of the spatial effect in deep excavations. However, the corner effects of the deep excavation with multi exposed corners have not been widely investigated and addressed in the previous literature. Based on the long and narrow deep excavation project of two square crossing of utility tunnels in a soft ground of Hainan, three dimensional numerical models of two typical construction programs are established using a commercial finite element software Plaxis 3D. Comparison and analysis of ground settlement caused by excavation, the deformation of the support structure, and the supporting axial force are performed. At the same time, the impacts of the corner effect on the distribution characteristics of these aforementioned studies are further discussed. The calculated results show that the maximum ground surface settlement of the long and narrow deep excavation for the utility tunnel varies between 0.11% He~0.67% He(He is excavation depth) under the two typical construction modes. The reasonable upper and lower bounds among the maximum lateral displacement of the steel sheet pile and excavation depth are 0.25% He and 1.35% He, respectively. On the whole, the maximum ground settlement of the soil around the excavation and lateral deformation of the supporting structure under the circumstance of construction program Ⅱ are lower than that in the condition of construction program Ⅰ. During the excavation process, it is worth noting that both two free surfaces of the exposed corner all have the remarkable corner effects under the circumstance of construction program Ⅱ, while the exposed corners in only one direction show the obvious corner effects under the circumstance of the construction program Ⅰ after their formation. The range of influence of the corner effects is approximately 2 times excavation depths. Within that range, the ground settlement, the deformation of the supporting structure and strut axial forces are all significantly lower than those in areas exceeding the coverage of the corner effects. The study suggests that if the influence of the corner effects and the degree of exertion are properly considered in the design of deep foundation pits with multi exposed corners at the intersections of utility tunnels, the project cost can be reduced to some extent.

       

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