【作者】 李彬；

【导师】 孙晓静；

【作者基本信息】 北京交通大学 ， 隧道与地下工程， 2017， 硕士

【摘要】 城市轨道交通为人们带来出行便利的同时,也引起了振动、噪声等环境问题,严重影响到沿线居民的工作和日常生活、建筑物的安全、精密仪器设备的正常使用等。为了减轻轨道交通振动对环境的影响,建设单位使用了大量振源减振措施,但这些减振措施大多依靠单纯降低轨道系统刚度进行减振,不仅增加了轨道投资,还恶化了轮轨关系,导致钢轨异常波磨的产生。其结果不但增大了振动和噪声,还为轨道交通的安全运营埋下隐患。基于此,业内人士提出应将减振部位下移,通过增加参振质量、阻尼吸振等方式进行减振。橡胶混凝土隔振基础是一种新型的减振产品,它将整个基础、道床及轨道系统作为参振质量,利用材料阻尼特性吸收耗散振动能量进行减振,并且成本低,可以作为整条线路使用的基础减振措施进行应用,从而降低全线的振动影响水平,同时在振动敏感地段配合采用其他减振产品,以期满足全线环境振动要求。本文依托国家自然科学基金项目“橡胶混凝土隔振基础减振降噪研究”(No.51408033),以C40混凝土为基准混凝土,研究适用于轨道交通的橡胶混凝土配合比,并对其减振性能进行预测分析。首先利用实验室试验研究了不同配合比的橡胶混凝土静力及动力性能,然后筛选出其中3种满足轨道交通设计要求并具备较好的动力性能的橡胶混凝土配合比,采用数值模拟方法进行橡胶混凝土减振道床减振性能预测分析,最后进行了橡胶混凝土减振道床的选型分析。本文的主要研究内容及结论如下:1.橡胶混凝土静力性能试验以C40混凝土为基准混凝土,首先根据不同的橡胶掺量(0%～50%),设计了15种配合比,进行橡胶混凝土的立方体抗压强度试验。然后根据试验结果选取其中7种配合比,进一步研究橡胶混凝土的轴心抗压强度、静力受压弹性模量、劈裂抗拉强度和抗折强度。试验结果表明:掺入橡胶颗粒会明显地降低混凝土的各项静力性能,并且橡胶掺量越大,混凝土的静力性能下降越多;掺入橡胶颗粒可以提高混凝土的韧性,减缓试件破坏过程中裂缝的发展,减缓了微裂纹产生发展所导致的混凝土断裂;橡胶混凝土的破坏属于延性破坏。2.橡胶混凝土动力性能试验同样选择静力试验选择的7种橡胶混凝土配合比,进行橡胶混凝土的动力性能试验研究,包括动弹性模量及阻尼比。试验结果表明:掺入橡胶颗粒会降低混凝土的动弹性模量,而且橡胶掺量越大,动弹性模量下降越多;掺入橡胶颗粒可以明显的提高混凝土的阻尼比,橡胶混凝土的阻尼比随着橡胶掺量的增加基本呈线性增加,橡胶掺量每增加1%,橡胶混凝土的阻尼比约增加0.023%。当掺量不高于23%时橡胶混凝土能够满足轨道交通设计规范要求,并且具有较好的动力性能,能够用于轨道交通减振。3.橡胶混凝土减振道床减振性能预测分析根据橡胶混凝土静力及动力试验分析结果,选择其中3种配合比,采用数值模拟方法,建立普通混凝土(SC)整体道床和橡胶混凝土(RC-10,RC-15,RC-23)减振道床等4种工况的三维动力有限元模型,研究橡胶混凝土减振道床的减振性能。结果表明:橡胶混凝土减振道床具有较好的减振效果,橡胶掺量越高,橡胶混凝土减振道床的减振效果越好;不同橡胶掺量的橡胶混凝土减振道床在地表0～30m范围内的Z振级插入损失在0.34～4.38dB之间。4.橡胶混凝土减振道床选型分析在满足安全性,耐久性和经济性的条件下应尽量选择高橡胶掺量的橡胶混凝土减振道床,以达到更好的减振效果。根据本文的研究成果,建议采用以C40为基准混凝土,橡胶掺量为23%的橡胶混凝土制作减振道床。橡胶混凝土减振道床轨道结构的单线每公里造价约为377万元,同普通混凝土整体道床轨道结构的造价基本相当。更多还原

【Abstract】 The urban rail transit brings convenience for people,but at the same time,it causes some environmental problems such as vibration and noise,which seriously affects the work and daily life of residents along the line,the safety of surrounding building and the precision of precision instruments and equipment.In order to reduce the impact of the vibration induced by rail transit on the environment,a variety of vibration mitigation measures have been used.But most of these measures simply ruduce the stiffness of the rail system.It increases the investment of rail and worsens the interaction of wheel and rail,which causes abnormal rail corrugation.The abnormal rail corrugation increases the vibration and noise,and it is harmful to the safety operation of rail transit.So some experts suggest that vibration reduction position should be moved down and increasing the quality and damping to reduce the vibration.Rubberized concrete vibration insulating foundation is a new type of vibration mitigation measure.It could absorb the vibration energy because of its material damping characteristics,and its cost is low so it can be used as the base mitigation measure for the whole line to reduce the vibration of the whole line.In vibration sensitive areas,rubberized concrete vibration insulating foundation and other vibration reduction measures could be used at the same time to meet the environmental vibration requirements of the whole line.This dissertation is supported by the projects of National Science Foundation of China named Research on the Vibration Attenuation of Rubberized Concrete Vibration Insulating Foundation(No.51408033).In this dissertation,the rubberized concrete mix proportion applied to rail transit is researched,and the vibration reduction performance of the rubberized concrete monolithic roadbed.Firstly,the mechanical properties and dynamic performance of different mix proportion of rubberized concrete is researched by laboratory test.Rubberized concrete can meet the requirements of rail transit design specifications and has good dynamic performance when the rubber content is not higher than 23%,and it can be used for rail transit vibration reduction.Secondly,3 kinds of mix proportion of rubberized concrete which can meet the requirements of rail transit design specifications and have good dynamic performance are selected,and then the vibration reduction performance of the rubberized concrete roadbed is predicted through the numerical simulation method.Finaly,the selection analysis of rubberized concrete roadbed is done.The main contents and conclusions of this dissertation are as follows:1.The mechanical properties test of rubberized concreteIn this test,the control concrete is C40 concrete.First,15 kinds of mix proportion of rubberized concrete are designed according to different contents of rubber particles,and the compressive strength of rubberized concrete is researched.Then,7 kinds of mix proportion of rubberized concrete is chosed according to the test result,and then the axial compressive strength,static compression modulus,splitting tensile strength and flexural strength of rubberized concrete are researched.The results show that the incorporation of rubber particles can significantly reduce the mechanical properties of concrete,and the greater the rubber content,the more the static performance of concrete decreases.The incorporation of rubber particles can improve the toughness of concrete and reduce the development of cracks in the process of failure.The destruction of rubber concrete is ductile damage.2.The dynamic performance test of rubberized concreteAccording to the results of mechanical properties test,7 kinds of mix proportion of rubberized concrete are chosed.The dynamic performance including dynamic elastic modulus and damping ratio of rubberized concrete is researched.The results show that the incorporation of rubber particles can significantly reduce the dynamic elastic modulus of concrete.The greater the rubber content,the more the dynamic elastic modulus of concrete decreases.The incorporation of rubber particles can significantly increase the damping ratio of concrete.The damping ratio of rubber concrete increases linearly with the increase of rubber content,and rubber content increased by 1%,the damping ratio increased by about 0.023%.Rubberized concrete can meet the requirements of rail transit design specifications and has good dynamic performance when the rubber content is not higher than 23%,and it can be used for rail transit vibration reduction.3.Predictive analysis of the vibration reduction performance of the rubberized concrete monolithic roadbedAccording to the results of mechanical properties and dynamic performance test,3 kinds of mix proportion of rubberized concrete are chosed.The three-dimensional dynamic finite element model of the the rubberized concrete(RC-10,RC-15,RC-23)roadbed and ordinary concrete(SC)monolithic roadbed are set up,and the vibration reduction performance of the rubberized concrete roadbed.The results show that rubberized concrete roadbed has a good vibration reduction performance.The greater the rubber content,the better the vibration reduction performance.The Z-level insertion loss of rubberized concrete roadbed is between 0.34-4.38dB on the surface of 0～30m.4.The selection analysis of rubberized concrete monolithic roadbedUnder conditions of safety,durability and economy,the rubberized concrete roadbed with higher rubber content is more beneficial to a good vibration reduction performance.According to the research results,the rubberized concrete roadbed with 23%rubber content is recommended,and its control concrete is C40 concrete.The single-line cost of rubberized concrete roadbed is about 3.77 million per kilometer,which is basically equal to the cost of general concrete monolithic roadbed track structure.更多还原