桩排距对双排抗滑桩内力的影响

双排桩结构具有复杂的受力特性。建立有限元模型,分析了不同桩排距条件下前后两排抗滑桩的受力状况。分析结果显示:桩排距越大,后排桩的弯矩和剪力也就越大,而前排桩的弯矩和剪力却越小。双排桩的前后两排桩不能同时发挥抗滑作用。随着桩排距增大,前排抗滑桩的抗滑效果越来越差;双排桩合并为单排桩,提高了抗滑桩的刚度,具有更强的抵抗滑坡体变形的能力,桩的受力也更加合理。当不得不采用双排桩时,应该选择适当的桩排距。另外,通过对浙江杭金衢高速公路K103滑坡双排桩应力与位移的监测分析发现,前排桩的应力与变形均小于后排桩,与有限元分析结果相吻合。

Effect of pile row distance on internal stress of double-row anti-slide piles

The structure of double-row piles was a complex mechanical characteristics.A finite element model was established and the mechanical characteristics of the front and back rows of piles at different row distances were discussed.It was indicated that the larger the row distance,the larger the horizontal displacement of the landslides and the bending moments and shear forces in the back row of piles,and the smaller the bending moments and shear forces in the front row of piles.The two rows of the double-row piles couldn’t display their sliding resistances simultaneously,and when the pile row distance increased,the effectiveness of sliding resistance of piles in front row became worse;when the double-row piles were merged into the single-row piles,the rigidity and the ability of the anti-slide piles were increased to resist the deformation of the landslide body and the piles were also stressed more rationally.When the two-row piles must be used,appropriate pile row distance should be chosen.On the other hand,through monitoring and analysis of the stresses and displacements of the double-row piles for the K103 landslide of Hangzhou-Jinhua-Quzhou Expressway in Zhejiang Province,the stresses and displacements of piles in front row were all smaller than those in the back one,and these were consistent with the results of finite element analysis.