全埋刚架抗滑桩参数影响数值模拟研究

Numerical Simulation on the Influence of Parameters of Fully Buried Rigid Frame Anti-slide Piles

针对某实际边坡工程,依据混凝土用量相等原则,将原文献中得到的最优单排抗滑桩转化为全埋刚架桩,并采用有限元软件ABAQUS建立其三维有限元模型,并与最优单排抗滑桩进行对比分析。由于全埋刚架桩更具有抗滑优势,可提高边坡稳定性,考虑刚架桩桩底支承约束条件、后排桩长和连梁高度等参数的变化对边坡和桩身的影响,均设置5种工况进行数值模拟计算。结果表明:后排桩长增加,前后排桩弯矩差逐渐减小,分布趋于均匀,但存在一个最优长度;连梁刚度增加,有利于减小边坡和桩身位移,后排桩的最大负弯矩作用点的位置发生在连梁高度的1.34~1.35倍处,前排桩最大负弯矩发生的位置逐渐向连梁底部靠近。为充分发挥前后排桩材料属性,以及提高刚架桩的整体抗滑能力,建议桩底约束设置为后排桩桩底固定前排桩桩底铰支或两桩底端均铰支。

Focusing on an actual slope engineering project,this work firstly developed a three-dimensional finite element model based on the finite element software ABAQUS,to analyze the optimal single row anti slip pile obtained in a literature which is transformed into a fully buried rigid frame pile based on the principle of equal concrete dosage.The result was compared and analyzed with the optimal single row anti slip pile.It is shown that fully buried rigid frame piles have more anti slip advantages and improve slope stability.Secondly,considering the influence of parameters such as the support constraint conditions at the bottom of the rigid frame pile,the length of the rear pile,and the height of the connecting beam on the slope and pile body,five working conditions are set up for numerical simulation calculations,aiming to provide reference for the design of rigid frame piles.The results indicate that to fully utilize the material properties of the front and rear piles and improve the overall anti-sliding capacity of the rigid frame pile,it is recommended that the pile bottom constraints be set as fixed at the bottom of the rear pile and hinged at the bottom of the front pile,or both pile bottoms are hinged.As the length of the rear pile increases,the difference in bending moments between the front and rear piles gradually decreases,and the distribution becomes more uniform,but there is an optimal length.The increase in the height of the connecting beam is beneficial for reducing the displacement of the slope and pile body.The position of the maximum negative bending moment acting on the rear pile occurs at 1.34 to 1.35 times the height of the connecting beam,and the position where the maximum negative bending moment occurs in the front pile gradually moves closer to the bottom of the connecting beam.