# Simulation Study on Ground Vibration Reduction Measures of the Elevated Subway Line
## 1 Introduction  
Urban rail transit has become an irreplaceable mode of transportation for urban residents, which brings us fast and convenient travel at the same time but also brings some new problems. In recent years, the impact of environmental vibration along the urban rail transit line has attracted more and more attention [1, 2]. The vibration response caused by urban rail transit spreads outward to produce secondary vibration and noise on the surrounding buildings, and people's life and work are affected to different degrees [3, 4, 5]. Therefore, it is necessary to study the environmental vibration caused by urban rail transportation. For the ground vibration problem caused by urban rail train operation, there have been many related studies, and the assessment of the ground vibration problem mainly includes empirical modeling [6], experimental analysis [7, 8], and simulation prediction [9, 10]. Many scholars have conducted relevant studies. [PERSON] et al. [11] developed empirical equations for ground vibration prediction and verified them with field measurements at Delhi Metro station sites with a maximum error of 2.66 percent and a minimum error of 0.84 percent in the prediction. [PERSON] et al. [12] developed an analytical model to analyze the amplification of ground vibration under different buried loads in underground tunnels. [PERSON] et al. [13] analytically investigated the vertical vibration of the tunnel wall and the ground above the tunnel under different soft and rocky geological conditions at 0, 15 m, and 30 m horizontaldistances from the tunnel center line based on measured data. With the improvement in computing power, numerical simulation has become an effective method to predict train-induced ground vibration. [PERSON] et al. [14] established a sliced finite element-finite element coupled model to analyze the environmental vibration of underground tunnel trains and compared the measured results. The transmission characteristics of the environmental vibration of metro trains and the effects of rail mat stiffness and train speed on the environmental vibration of metro trains were investigated. [PERSON] et al. [15], based on the probability density evolution method and random field theory, established a coupled model of metro train-track-shield tunnel-foundation soil and analyzed the relationship between surface vibration displacement and train speed. [PERSON] et al. [16] proposed a new periodic tunnel-soil model with a track slab to simulate the propagation of train-induced vibrations. Based on the simulation prediction results, reasonable damping measures are proposed to reduce environmental vibration, which is more conducive to saving resources and maintenance costs [17; 18]. Depending on the propagation path of the vibration, appropriate damping measures can be taken at the vibration source, propagation path, and vibration receiver [19; 20; 21]. In the process of line design, the vibration analysis of train operation can timely find out the impact of vibration induced by train operation on the environment, and take corresponding countermeasures in time to reduce the high cost and adverse impact of remedial measures after line operation [22]. Ground vibration control can be achieved by installing damping fasteners and adjusting the spacing of the sleepers [23]. The installation of vibration damping pads and steel spring floating plates has been shown to be more effective for ground vibration control [24; 25; 26]. [PERSON] et al. [27] numerically analyzed the floor vibration of a metro vehicle section and discussed the effect of train speed fastener configuration on the response of the floor vibration of the section. [PERSON] et al. [28] developed a new type of floating plate track vibration isolator by combining particle damping reduction and bandgap vibration isolation. In the frequency band of 50-150 Hz, the new floating plate track vibration isolator has a better vibration damping effect. [PERSON] et al.