Optimal Analysis Of The Effect Test Of Vibration Damping Barrier On The Impact Of Subway Operation On Environmental Vibration

With the continuous deepening of the reform and opening up process,the development of efficient and convenient transportation systems has always been an important goal of urban construction.As a kind of diversified transportation modes,the subway has gradually become one of the focal points of the transportation layout of various large and medium-sized cities.With the laying of subway tunnels and the operation of subway trains,their vibration hazards to the environment along the line have caused great impact and threats to the physical and mental health of the surrounding residents and the maintenance of expensive precision instruments in nearby universities or scientific research institutions.People are paying more and more attention to the adverse effects caused by vibration hazards.Therefore,the vibration reduction measures of environmental vibration caused by subway train operation have become an important research direction.Setting the vibration-damping barrier as a vibration-damping measure on the vibration propagation path of the operating subway has the characteristics of simplicity and high efficiency,but there are still many blind spots worthy of in-depth study on its vibration-damping effect and characteristics.Because the burial depth of subway tunnels is constantly changing,for deeper subway tunnels,due to the vibration damping effect of the surrounding rock and soil media,the vibration wave when it is transmitted to the ground buildings is already weak.Therefore,the research direction of this paper is mainly the vibration isolation and vibration reduction measures of the near-shallow surface vibration waves generated by the subway.By blocking the propagation path,a barrier is placed near the protector to achieve the ultimate purpose of vibration reduction.The thesis first analyzes and discusses the propagation of vibration waves and the principle of vibration damping of the barrier.In the research process of the trench barrier,the three-dimensional finite element numerical analysis model was established by the finite element software MIDAS GTS NX to analyze the elements of different sizes Of the length,width and depth)on the damping effect of the empty trench barrier,and the grouping and comparison analysis of the vibration damping effect of the shallow vibration source.At the same time,the test data and relevant measured data obtained from the literature are compared with the results of the finite element analysis to verify the rationality of the numerical analysis model and related parameters in this paper,so that the results are unified.Finally,starting from the engineering practice,through the finite element numerical analysis model,the influence of different properties of the filling material in the filling barrier on the vibration damping effect is further studied.While summarizing the laws,some suggestions on engineering application are put forward.The main research contents of this article include:(1)Discusses the propagation and attenuation of vibration waves in soil,introduces the basic principles of continuous barrier vibration reduction,and provides a theoretical basis for subsequent finite element numerical simulation analysis.(2)The characteristics of several commonly used soil constitutive models and related theories of MIDAS GTS NX software are introduced respectively.Combined with the characteristics of this subject,the constitutive model of the soil layer adopts the Mohr-Coulomb model.Considering that the dynamic problems of this study need to eliminate the rebound of the vibration wave at the boundary,several boundary conditions of the finite element software MIDAS GTS NX are introduced and compared in sequence.Finally,it is considered that the viscoelastic boundary is selected as the subject of this research The boundary conditions of finite element numerical simulation are more reasonable.(3)On the green ground near the central sports ground of Guangzhou University,the measured waveform data under the action of artificial hammer vibration was collected.The selected scientific research vibratory hammer is very suitable for imitating the low-frequency vibration generated by the heavy structure.Selected waveforms for numerical analysis studies.(4)Using the finite element numerical analysis method,the damping characteristics of the size of the trench barrier(the length,width and depth of the barrier)under the action of artificial hammering vibration waves are discussed,and the different influencing factors are analyzed The effect of the effect;fitting the evaluation relationship of the vibration damping effect and vibration damping efficiency;giving the recommended value of the reasonable size of the empty trench barrier.(5)Discusses the basic theory of impedance ratio,simulates different filled barriers through the finite element software MIDAS GTS NX,compares and analyzes the properties of different filled materials in the barrier,and puts forward some suggestions from practical engineering applications based on the results.