Dynamic Analysis Of Tram Under Subgrade Settlement And Research On Safe Operation Speed

As a non-polluting,large-capacity and low-cost public transportation,modern trams can effectively relieve the pressure of urban ground traffic and meet people’s travel needs.However,with the cumulative operation of the tram,the subgrade will inevitably produce uneven settlement.The uneven settlement of the subgrade greatly affects the running speed of the tram,which poses a challenge to the safe and efficient operation of the tram.Therefore,it has important meaning to find out the relationship between the uneven subgrade settlement and the safe operation speed of trams.This paper takes Nanjing Qilin tram as the research object.According to theoretical analysis,numerical simulation and prediction,this paper deeply study the connection of the uneven settlement of the subgrade and the safe operation speed of the tram.The main research work includes the following aspects:(1)Taking Nanjing Qilin tram as the research object,the finite element model of the coupled structure dynamics of track-subgrade-vehicle is established.Taking into account the relevant dynamic characteristics of the vehicle suspension system,the tram kinematics equation is established according to D’Alembert’s principle;the relevant degrees of freedom of the vehicle bogie are limited,and the real running state of the tram is simulated;The linear contact model and creep theory are used to establish the wheel-rail contact model to realize the coupling between the vehicle and the track.(2)Using the finite element analysis software ABAQUS,the dynamic characteristics of the track under the uneven settlement of the subgrade are deeply studied.Comprehensively analyze the dynamic response of each track structure when the tram runs through different positions of the subsidence section,quantify the difference in the dynamic performance of each track structure when the subgrade subsides unevenly,and deeply study the influence of subgrade uneven settlement on the track structure,the connection of the uneven settlement of the subgrade and the dynamic response of the track structure is obtained.After the comparison and analysis,it is found that with the increase of the subgrade settlement,the dynamic indicators of each track structure have increased to varying degrees,and the track where the subgrade settlement is the largest is most vulnerable to damage,which is an effective way to effectively control the subgrade settlement to implement Subgrade maintenance provides a basis for decision-making.(3)The safe operation speed of trams under different subgrade settlements is studied in detail.According to the finite element simulation analysis of the dynamic characteristics of the rail system,the variation law of the influence of the tram operating speed on the dynamics of the rail system under different settlement conditions is obtained;in the analysis of the safety and stability indicators of tram operation On the basis of,the influence law of subgrade settlement and operating speed on derailment coefficient,wheel load reduction rate and vehicle body vibration acceleration is studied,and a method for determining the safe operating speed of trams under subgrade settlement is proposed,which is helpful for formulating different settlements.Provide technical support for the safe operation speed of trams under the scale.(4)Taking Nanjing Qilin tram line as the research object,combined with the actual monitoring data,the LSTM neural network is used to predict the subgrade settlement,and the subgrade settlement in the next five years is obtained.On this basis,aiming at the safety and stability of the tram,a speed control table for the safe operation of the Kylin tram is initially formulated.The research results of this paper will provide reference for the formulation of the safe operation speed of Nanjing Qilin tram,and also provide decision support for the management and maintenance of tram lines.