深基坑多级支护破坏模式及稳定性参数分析
Parametric analysis of failure modes and stability of muti-level retaining structure in deep excavations
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摘要: 对于软土地区的大面积、深开挖基坑,已经出现了一些采用排桩与排桩或重力式挡墙与排桩相结合的多级支护形式。采用有限元分析了双排桩与单排桩组成的多级支护形式的破坏模式及破坏机理,并对单排桩桩长、两级支护结构间的水平距离以及两级开挖的深度比等对基坑稳定性的影响进行了参数分析。研究结果表明:当两级支护之间距离不变时,单排桩桩长达到一定数值后对多级支护结构的抗倾覆稳定性影响较大;两级支护结构间的水平间距相对于开挖深度较小的时候,两级支护间距离的变化对基坑抗倾覆稳定性有较大影响;而开挖深度比的影响与两级支护间的水平距离大小有关。Abstract: The multi-level retaining methods such as two-level single-row retaining piles or two-level single-row retaining piles and gravity retaining wall are applied in some large area deep foundation excavation projects. By using the finite element method, the failure modes and stability of multi-level retaining structure composed of one level of double-row piles and the other level of single-row are studied. Parametric study is performed to further analyze the effects of the length of single-row piles, distance between the two-level retaining piles and depth of the two levels on the stability of multi-level retaining structure. The results show that the length of single-row retaining pile can produce significant effect on the overturning stability when the length is longer than a certain length. Only when the distance of the two-level retaining piles is small compared to the excavation depth, it can have a remarkable effect on the overturning stability. The effect of ratio of the depth of the two-level retaining piles on the overturning stability is related to their horizontal distance.