Design And Study On Vibration Reduction Performance Of The Rubber Concrete Monolithic Roadbed

ABSTRACT:The unban rail transit is in a rapid development period in recent years, bringing great convenience to people as well as increasingly serious environmental vibration problems. The vibration makes the damages to the buildings and precision instruments, also having a great influence to our life. Thus a variety of vibration reduction measures are developed and widely used in urban rail transit which solve the above problem in a large extent. However there are still many disadvantages behind those measures:the rising construction cost of the unban rail transit and the growing problem of rail corrugation. Therefore, how to solve these problems and seek the sustainable development of urban rail transit has very realistic significance.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 view of the problems on the vibration reduction measures of the unban rail transit, this paper proposes a new type of vibration reduction measures:the rubber concrete monolithic roadbed. It completes the design of the rubber concrete monolithic roadbed and evaluates the vibration reduction performance by the the finite element analysis method and elastic foundation composite beam analytic method. The main research contents of this dissertation are as follows:1. Design of the rubber concrete monolithic roadbedBased on the background of west extension project of Beijing metro line6, referring to the related national and industry standards, according to the vibration standard section type of the horseshoe、rectangular and circular tunnel, The thesis protocols the size of the rubber concrete monolithic roadbed on three types.It analyzes the internal force of the rubber concrete monolithic roadbed on different types by the finite element analysis method and elastic foundation composite beam analytic method, using allowable stress method and the maximum tensile stress method for strength checked and reinforcement design. On the basis for three types of rubber concrete monolithic roadbed, the vibration test-bed is designed, laying a foundation for further field test.2. The vibration reduction performance analysis of the rubber concrete monolithic roadbedThe dissertation studys the modeling process and parameters selection of the "rail-tunnel-formation" three-dimensional dynamic finite element model and establishes the model of the Track Vibration Attenuation&Control(Lab-TVAC) in the Beijing jiaotong university. Combining with the measured datas, through checking the parameters of the dynamic finite element model and adjusting the model parameters, this dissertation obtains the dynamic finite element model which can be accurate to analyze vibration response.By establishing the monolithic roadbed under the horseshoe, rectangular and circular tunnelstyles, it accomplishes the analysis of dynamic characteristics which studys the rubber concrete and ordinary concrete monolithic roadbed natural frequency and vibration mode by the modal analysis.Finally, the rail-tunnel-formation three-dimensional dynamic finite element model of the the rubber concrete and ordinary concrete under three kinds of tunnel types are set up. Dynamic calculation is achieved on the train vibration load which has been solved. At last this dissertation evaluates the vibration damping performance of the rubber concrete monolithic roadbed by the indicators of vibration reduction, such as the spectrum diagram, insertion loss, the transmission loss.