微型桩破坏机理的数值模拟

Numerical Simulation of Failure Mechanism of Micro-piles

强度折减法与具有拉和剪破坏分析功能的有限差分程序FLAC3D相结合,对同一排内均匀布置的桩心配筋微型桩进行数值分析。岩土体、桩体均采用实体单元,模型采用摩尔-库仑理想弹塑性本构模型,依据微型桩的受力特点考虑了桩体进入塑性状态,得到了单排微型桩和具有纵向连系梁的三排微型桩的应力、应变分布规律和破坏机理。计算表明,单排桩的破坏主要为滑带处的剪切破坏,三排桩为滑带处的拉剪破坏,桩体所承受的最大弯矩和剪力均位于滑带处,混凝土主要起抗剪作用,钢筋提供抗拉和抗剪能力。

This paper analyzes the center reinforced micro-piles evenly arranged in the same row based on strengthen reduction and the finite difference program FLAC3D with function analyze tension and shear failure. Solid elements and Mohr-Coulomb ideal elastoplastic model are used for rock, soil and piles. The authors consider the mi- cro-plies getting into plastic state based on its mechanical characteristics, then obtaining the regularities of stress- strain distribution and the failure mechanisms of single-row micro-piles and three-row micro-piles with vertical tie beam. The result shows that the failure of single-row piles is mainly the shear failure in the slip zone and the failure of three-row piles is tension-shear failure in the slip zone. The maximum bending moment and shear force of the plies are all located in the slip zone. The concrete mainly works for shear resistance and the reinforcement works for tension and shear resistance.