【作者】 王燕；

【导师】 苏谦；

【作者基本信息】 西南交通大学 ， 道路与铁道工程， 2010， 硕士

【摘要】 桩板式低矮路堤主要由钢筋混凝土桩基、桩周土体和承台板及填方路基四大部分组成；无论是在构造处理方面,还是在调整不均匀沉降及控制工后沉降方面,桩板式低矮路堤都是较佳的结构形式。大型激振设备在高速铁路未铺轨的路基上的应用,仅限于对测试动力响应的动位移、速度及加速度分析,而相关的理论研究较少。我国自20世纪70年代起在动力机器基础振动学科中就存在着质-弹-阻理论体系和弹性半空间理论的讨论；如何通过分析和试验修改振动参数,建立以弹性半空间理论为基础的等效质-弹-阻模型就成为当前基础动力学研究中较为迫切的课题。因此,针对目前大型激振设备动力分析理论和计算方法编制相关软件,提出基于激振器与路基相互作用的一套计算方法,结合郑西客运专线桩板结构现场激振试验,验证了该计算方法的正确性,对指导进一步的现场激振试验具有重要的意义。首先,对目前大型激振设备动力分析理论、计算方法及测试技术进行研究分析,根据文中提出的相关理论,用Visual Basic 6.0编程计算,包括六个窗体和一个一般模块。六个窗体分别为DTS-1主窗体；激振器参数窗体即激励参数窗体；天然地基窗体包括在天然地基上激振时的计算方法-动力机器基础设计规范、反力代入法、比拟法及方程对等法；桩基窗体包括在桩基上激振时的计算方法-动力机器基础设计规范及群桩基法；动力反应窗体包括定参集总体系和变参集总体系,通过在天然地基或桩基窗体所得集总体系参振参数计算其动力反应；现场测定窗体是通过激振器现场测试反算动力参数计算方法-点峰法和低频求刚度法。参考天然地基、桩基等计算方法,提出一套实用的计算方法。其次,建立激振器-桩板式低矮路堤的三维动力仿真模型,对激振荷载作用下桩板式路堤的动力性能进行研究,分析不同激振频率及加载位置对桩板式路堤的峰值动力响应影响,得出动应力随频率增加近似线性增大,加速度随频率近似4次多项式关系,速度随频率近似3次多项式关系,动位移随频率近似2次多项式关系,符合振动力学关系；不同加载位置对桩板式路堤各部件的动力响应峰值略有不同程度的影响,但数值相差均较小,可近似认为在不同位置激振,桩板式低矮路堤的动力响应无影响。最后,通过解析计算与数值计算的对比分析,两种计算方法的动位移基本上保持在同一水平,其中数值计算结果偏大。两种计算方法的动应力增长趋势一致；当激振频率小于20Hz时,值相差不大,激振频率大于20Hz后,解析计算值明显大于数值计算值；故现场激振试验时,估算动应力当激振频率大于20Hz时应乘以一定的折减系数。更多还原

【Abstract】 Pile-board structure of low embankment is mainly composed of four parts:reinforced piles, soil around piles, platform plate and fill subgrade, making it a kind of excellent structure style both in structure treatment and in adjusting the uneven settlement and controlling the post-construction settlement. Large-scale excitation equipment is limited to testing dynamic displacement, velocity and acceleration of dynamic response in high-speed railway subgrade before laying track, to which minor theoretical research is related. Since 1970s in China, discussions about the mass-spring-damper system and elastic half-space theory have already existed in the basic vibration subjects of dynamic machine;how to modify the vibration parameters by analyzing and testing and establish equivalent mass-spring-damper model based on elastic half space theory have been the urgent issue in the kinetic studies of basic dynamics.Therefore, according to current dynamic analysis theories and calculating method of large-scale excitation equipment, a set of calculating method based on the interaction of the vibration exciter and the subgrade was put forward, combined with field excitation test of pile-board structure of Zhengzhou-Xi’an high-speed railway, the correctness of this calculation was verified. Thus great significance engendered to guide further field excitation of pile-board subgrade of Beijing-Shanghai high-speed railway.Firstly, according to the current theory, calculation and testing technology of large-scale excitation equipment, Visual Basic 6.0 was adapted to programming calculation, including six forms and a general module:DTS-1 main form, excitation parameters form, natural foundation form, pile form, dynamic response form and field test form. Dynamic machine foundation design specification, anti-force substitution, analogy and reciprocity law equation were included in natural foundation form; Dynamic machine foundation design specification and group pile foundation design were included in pile form; dynamic response form included fixed and variable parameter system of natural ground and piles, from which dynamic response could be calculated; field test form was inverse dynamic parameter method of field vibration test, including point-peak method and low frequency peak demanding stiffness method. A set of practical calculation method referring to natural, pile and other kinds of foundation was proposed.Secondly, three-dimensional dynamic simulation model of vibration exciter-pile-board structure of low embankment was established to study dynamic performance of the Pile-board structure of low embankment under excitation load and the effects to dynamic response peaks for different vibration frequency and load position, dynamic stress increased linearly with increasing frequency, acceleration was approximately four times polynomial relations with frequency, the speed was approximately three times polynomial relations with frequency while dynamic displacement was approximately two times polynomial relations with frequency, which was consistent with mechanical vibration relationship; therefore, the effect of different load position to the dynamic response were slightly different, so load position was thought having no impact to the dynamic response.Finally, analytical calculation and numerical computation were comparatively analyzed, the dynamic displacement of the two methods remained essentially the same level, in which numerical computation results were relatively larger; the dynamic tress growth trends of the two methods were almost the same when the dynamic frequency was less than 20Hz, but when the dynamic frequency was greater than 20Hz, the result of analytical calculation was obviously bigger than numerical computation, so the dynamic stress should be multiplied by a certain reduction factor in the case of vibration frequency less than 20Hz in the field test.更多还原