混凝土预制桩在冲击荷载作用下的破坏机理研究
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(1 北京市建筑工程设计有限责任公司， 北京 100055； 2 中国科学院力学研究所， 北京 100190)[摘要] 建立了桩锤系统修正模型并推导冲击荷载修正公式，以基于连续介质力学的离散元方法(CDEM)的计算程序为平台，研究了打桩过程中混凝土预制桩的破坏机理，探讨了冲击荷载的特征和混凝土预制桩的非均匀性对应力波传播过程的影响。研究结果表明：在一定载荷条件及材料性质下，冲击荷载峰值对桩体受压或受拉破坏的影响有着规律性的变化；给出了基桩在不同支承条件下受冲击荷载作用时间影响的波动响应曲线；给出了混凝土预制桩的非均匀性（包括材料非均匀性和几何非均匀性）对冲击破坏特性的影响。对实际打桩工程有一定参考价值。[关键词] 数值模拟;桩锤系统;打桩模型;冲击荷载;非均匀性中图分类号：TU473.1+1 文献标识码：A 文章编号：1002-848X(2013)S1-0876-06Destructive mechanism of precast concrete piles under the impact loadZhang Yanan1, Feng Chun2, Li Shihai2Abstract：The pile hammer system model is established and the calculating formula for the impact load is gained. The platform of continuum media mechanics of discrete element method (CDEM) is used. The failure mechanism of precast concrete piles during pile driving is studied; the relationship between pile dynamic failure property and related influence factors is given. The results show that under the specific load and material properties，the failure of pile has regular changes under the effect of impact load peak value; The wave response curves with the variation of impact load time under different support conditions are given; impact failure characteristics of pile under the effect of nun-uniform of piles is gained. There are reference values for actual piling.Key words：numerical simulation;pile-hammer system;model of piling;impact load;non-uniformity
