滑体为黏土层的悬臂式抗滑桩三维土拱效应研究

发布时间：2019-06-27 16:19

【摘要】：为优化抗滑桩的设计,针对滑体为黏土层的悬臂式抗滑桩,基于ABAQUS软件构建了桩间距分别为3b、4b、5b、6b(b为矩形桩宽度)的4个三维有限元数值模型,分析顶下1、3、5、7、9、11m深度处的水平土拱效应,以研究竖向上水平土拱效应的变化即三维土拱效应.桩顶下1m处,桩间距为4b时桩后土拱中大主应力占桩后大主应力的95.3%,此时土拱抗滑性能发挥得最好.深度为5m时的大主应力云图中依然有十分明显的土拱,但是相较于较浅处其桩后壁处以及桩后土拱处的大主应力均为负值,说明随着滑坡推力的增大,逐渐大于桩后土拱的抗滑力,这时桩间土拱逐渐发挥作用,但此时桩后土拱并未破坏.桩顶以下7m处土拱在各桩间距下均有形成,但桩间土拱的拱高均有所降低,桩间土拱破坏后,大主应力的拱形弧线向桩间移动,新的桩间土拱再次形成,说明土拱的形成和破坏往往不是一次完成的,而是有几个往复的阶段.深度为9m时的桩后土拱比深度为7m时的桩后土拱承担了较小比例的滑坡推力,说明随着深度的增加,桩后土拱承担的滑坡推力的比重在下降.而当深度变为11m时,桩后土拱和桩间土拱已变得不太明显.三维土拱的拱高从桩顶向下逐渐减小,是由于滑体推力随深度由大变小造成的.本文的研究能为抗滑桩桩间距的合理设计提供参考.
[Abstract]:In order to optimize the design of anti-slide pile, four three-dimensional finite element numerical models with pile spacing of 3b, 5b and 6b (b is rectangular pile width) are constructed based on ABAQUS software for cantilever anti-slide pile with clay layer. The horizontal soil arch effect at the depth of 1, 3, 5, 9, 11 m below the top is analyzed in order to study the variation of vertical horizontal soil arch effect, that is, three-dimensional soil arch effect. 1 m below the top of the pile, when the pile spacing is 4 b, the large principal stress in the soil arch behind the pile accounts for 95.3% of the large principal stress behind the pile, and the anti-skid performance of the soil arch is the best. When the depth is 5 m, there are still very obvious soil arches in the cloud diagram, but compared with the shallow ones, the large principal stresses at the back wall of the pile and the soil arch behind the pile are negative, indicating that with the increase of the thrust of the landslide, the anti-skid force of the soil arch behind the pile is gradually greater than that of the soil arch behind the pile, and the soil arch between piles plays a role gradually, but the soil arch behind the pile is not destroyed at this time. The soil arch below the top of the pile is formed under the spacing of each pile, but the arch height of the soil arch between piles is reduced. After the failure of the soil arch between piles, the arch arc of large principal stress moves to the pile, and the new soil arch between piles is formed again, which indicates that the formation and failure of the soil arch are often not completed at one time, but have several reciprocating stages. When the depth is 9 m, the soil arch behind the pile bears a small proportion of landslide thrust when the depth is 7 m, which indicates that with the increase of depth, the proportion of landslide thrust borne by the soil arch behind the pile decreases. When the depth is 11 m, the soil arch behind the pile and the soil arch between the piles have become less obvious. The arch height of the three-dimensional soil arch decreases gradually from the top of the pile to the bottom, which is caused by the decrease of the thrust of the sliding body with the depth. The research in this paper can provide a reference for the reasonable design of the spacing of anti-slide piles.
【作者单位】：上海海事大学海洋科学与工程学院;
【基金】：国家自然科学基金面上项目(41372319)
【分类号】：TU473.1

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