软土基坑倾斜支护模型试验及变形控制研究

    Experimental study on inclined and vertical form retaining wall model and deformation control of soft soil foundation pit

    • 摘要: 倾斜支护结构在基坑工程中应用愈加广泛,虽倾斜支护结构能约束基坑变形,但深厚软土影响基坑发生持续变形。基于软土大型物理模型试验,设置倾斜支护结构(G1)、悬臂支护结构(G2)、通常配筋倾斜支护结构(G3)、添加反压混凝土的倾斜支护结构(G4)和预置反压混凝土的倾斜支护结构(G5)五种工况,考虑空间效应及时间效应对倾斜支护体系的影响,同时,对变形控制措施进行验证。结果表明:G1、G3、G4和G5桩顶水平位移均小于G2,且G4控制效果优于G5(E4);G4桩身变形均小于G1、G5,添加反压混凝土能够有效的减小倾斜支护结构变形;G1至G5时程曲线均呈现快速变形和稳定变形阶段,且添加反压混凝土会导致时程曲线存在下降阶段;在不同坑深时添加反压混凝土均能控制结构变形、减小土体变形。研究结论可为倾斜支护结构的变形控制措施和工程应用提供试验依据。

       

      Abstract: The inclined and vertical form retaining wall (IVFRW) has become increasingly popular in foundation pit engineering, owing to its effective deformation control capabilities. However, soft soil may induce progressive deformation, requiring improved stabilization measures. A large-scale physical model test is designed for soft soil, encompassing five working conditions: conventional IVFRW (G1), cantilever retaining wall (G2), generally reinforced IVFRW (G3), IVFRW with added counterweighted concrete (G4), and IVFRW with prefabricated counterweighted concrete (G5). The experiment considers spatial and temporal effects on IVFRW performance. Concurrently, the efficacy of deformation control measures is validated. The test results show that the horizontal displacement of the pile top in G1, G3, G4, and G5 exhibits a reduction compared to G2. Notably, G4 demonstrates greater displacement control efficiency than G5 (at E4). All deformation time-history curves exhibited distinct rapid-development and stabilization phases, with G2 and vertical piles showing the most pronounced time-dependent effects. In addition, the incorporation of counterweighted concrete introduced a descending phase in curves, indicating reduced deformation. Applying counterweighted concrete at different pit depths effectively limits structural deformation while decreasing soil deformation. These findings can inform deformation control measures and engineering applications for IVFRW.

       

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