组合桩锤锤击模型的数值分析
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摘要
为分析一个锤击周期内两个锤头连续锤击时对打桩锤锤击力的影响,将锤头结构设计为由上、下锤头和中间垫层组成的组合桩锤,用不同的集中质量块表示上锤头、下锤头、砧座和桩帽,用不同的并联的弹簧和阻尼器表示中间垫层和锤垫,用弹簧表示桩垫,用阻尼器表示桩,建立了平衡方程。采用量纲分析法推导出锤击力的数值解,分析了桩锤与垫层的分离情况,比较了组合桩锤各参数和垫层参数对锤击力的影响,并与普通桩锤产生的锤击力进行了比较。结果表明:将锤头设计为组合桩锤结构,使得锤击力波形出现多个峰值,且峰值减小,有效锤击时间加长。
In order to analyze the influence of two rams one by one impact in a cycle on the impact force of a pilehammer,numerical analysis model for a combined pile-hammer consisting of an upper ram and lower ram was presented.In the model,different lumped masses were taken as an upper ram,a lower ram,an anvil and a pile cap,different springs and dashpots were taken as a middle cushion and a ram cushion,a spring was taken as a pile cushion and a dashpot was taken as a pile. The equilibrium equations were establishe. Numerical solution to the impact force was derived with the dimensional analysis,the separation of a ram from its cushion and the separation of a pile from its cushion were considered,the influence of the combined pile-hammer's parameters on the impact force was analyzed,and the impact forces generated by a common pile-hammer and a combined pile-hammer were compared. Results showed that the combined pile-hammer structure makes the impact force have several smaller peaks and the effective impact time be longer.
In order to analyze the influence of two rams one by one impact in a cycle on the impact force of a pilehammer,numerical analysis model for a combined pile-hammer consisting of an upper ram and lower ram was presented.In the model,different lumped masses were taken as an upper ram,a lower ram,an anvil and a pile cap,different springs and dashpots were taken as a middle cushion and a ram cushion,a spring was taken as a pile cushion and a dashpot was taken as a pile. The equilibrium equations were establishe. Numerical solution to the impact force was derived with the dimensional analysis,the separation of a ram from its cushion and the separation of a pile from its cushion were considered,the influence of the combined pile-hammer's parameters on the impact force was analyzed,and the impact forces generated by a common pile-hammer and a combined pile-hammer were compared. Results showed that the combined pile-hammer structure makes the impact force have several smaller peaks and the effective impact time be longer.
引文
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[2]朱合华,谢永健,王怀忠.打桩锤击解析模型及垫层材料参数的优化[J].同济大学学报(自然科学版),2004,32(7):841-845.ZHU He-hua,XIE Yong-jian,WANG Huai-zhong.Analytical solution for pile hammer impact and application of optimum design technique for determining cushion parameters[J].Journal of Tongji University(Natural Science),2004,32(7):841-845.
[3]Sabellico A R.Pile driver pad[P].US3154155,Oct.27,1964.
[4]Guild C L.Hydraulic cushion block and impact type pile driving hammers[P].US3498391,Mar.3,1970.
[5]Ruppert R W.Pile hammer cushion apparatus[P].US3991833,Nov.16,1976.
[6]杨襄璧,刘德顺,胡均平.撞击回弹问题的理论研究[J].中国有色金属学报,1996,6(4):171-175.YANG Xiang-bi,LIU Des-hun,HU Jun-ping.Theoretical studies on rebound problem of impact[J].The Chinese Journal of Nonferrous Metals,1996,6(4):171-175.
[7]朱萍玉,杨襄璧,刘德顺.基于MATLAB的冲锤反演设计与数控加工初探[J].机械设计与制造,2002,4:81-83.ZHU Ping-yu,YANG Xiang-bi,LIU De-shun.Inverse design of impactors based on matlab[J].Machinery Design&Manufacture,2002,4:81-83.
[8]杨永海,吕景忠,隋振,等.加速下落冲击式液压桩锤设计[J].农业机械学报,2005,36(5):150-152.YANG Yong-hai,LJing-zhong,SUI Zhen,et al.Design of accelerated impact pile hammer[J].Transactions of the Chinese Society for Agricultural Machinery,2005,36(5):450-152.
[9]胡均平,郭勇,宋光伟,等.金属颗粒填充桩锤锤击模型的数值分析[J].中国公路学报,2010,23(2):122-126.HU Jun-ping,GUO Yong,SONG Guang-wei,et al.Numerical analysis for impact model of pile hammer filled with metal particles[J].China Journal of Highway and Transport,2010,23(2):122-126.
[10]Zhang Lei,Gong Xiao-nan,Yang Zhong-xuan,et al.Elastoplastic solutions for single piles under combined vertical and lateral loads[J].J.Cent.South Univ.Technol,2011,18:216-222.
[11]胡育佳.桩基非线性静动力学特性研究[D].上海:上海大学,2008.