中文摘要：

针对打桩过程中桩体容易损坏的现象,提出一种在锤体内腔填充质量块的组合锤头打桩的新型锤击模型。运用键合图理论对锤击系统建模,为模拟打桩反弹时各质量块与垫层接触、分离的非线性特性,引入开关类量的键合图元件功率结型结构（SPJ）,采用集中参数搭建锤击系统的键合图模型,据此建立可统一表达系统所有运动状态的数学模型。利用量纲一分析法推导锤击力的数值解,并基于Matlab软件仿真分析填充质量块和垫层参数对锤击力的影响。通过试验验证该模型的准确性。研究结果表明：采用组合锤头时,锤击力波形出现2个峰值,且峰值减小,这不仅可以保护桩体,而且可提高能量传递效率;各参数中,填充质量块和锤垫对锤击性能的影响最大,砧坐垫的影响次之,桩垫的影响最小。该模型可用于锤击系统的参数优化研究及动态特性分析。

英文摘要：

In view of the phenomenon of pile body damage in the process of pile driving, the impact model of composite hammer filled with mass in the inner cavity was proposed. The lumped parameter method was used to establish the bond graph model of impact model, which introduced the concept of switched power junctions（SPJ） to represent the nonlinear characteristics of contact and separation between masses and cushions, and then the system equations were derived from the model in a unified way. The method of dimensionless analysis was used to analyze the effect of various parameters on the impact force within the Matlab environment. The model was verified experimentally. The results show that the composite hammer causes a lower crest and a longer effective impact time as it has more than one force wave, which also protects the pile body and improves the efficiency of energy transfer. The filling mass and the hammer cushion have the greatest effects on the performance of the hammer, the anvil cushion is the second, and the pile cushion is the smallest.The method can be used to the optimum design and dynamic analysis of the hammer impact system.