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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.
In order to optimize the design of anti-slide piles, aiming at the cantilever anti-slide piles with sliding layers of clay, four three-dimensional finite element models with 3b, 4b, 5b and 6b piles were designed based on ABAQUS software Numerical model was used to analyze horizontal soil arching effect at the depths of 1, 3, 5, 7, 9 and 11 m to study the effect of three-dimensional soil arching on the vertical soil arching effect. 4b, the main principal stress in soil arching accounts for 95.3% of the principal stress after pile, and the anti-skid performance of soil arching is the best at this time.Under the depth of 5m, However, compared with the shallow post-pile at the back of the soil and the post-arch soil at the main principal stress are negative, indicating that with the increase of landslide thrust, gradually greater than the slip of soil arching after piles, then pile Soil arching gradually play a role, but this time the soil arching is not damaged after the pile top .7m below the top of the soil arches in each pile spacing are formed, but the soil arches between the piles arch height are reduced, the soil between the piles After the arch is destroyed, the arched arc of the main stress moves towards the piles, and the soil arches between the new piles form again, indicating that the formation and destruction of soil arches are often not completed in one time , But there are several stages of reciprocation.The soil arching behind the post-pile with a depth of 9m is smaller than that of the soil arches with a depth of 7m, indicating that as the depth increases, Of the landslide thrust is declining.While the depth becomes 11m, the soil arching between piles and piles has become less obvious.Arch height of the three-dimensional soil arches gradually decreases from the top of the pile due to the slippery The thrust of the body decreases with the depth of the body.The research in this paper can provide reference for the reasonable design of anti-slide pile spacing.