Fast Prediction Method Of Environmental Impact Of Subway Train Based On Database

Rail transit has brought environmental vibration problems that can not be ignored,which not only affects the normal life and work needs of residents,but also affects the buildings along the line(including ancient buildings),and may even lead to the failure of precision instruments and equipment to work properly.With the rapid development of rail transit and cities,it can be predicted that this problem will become more and more serious.If the vibration prediction can be carried out quickly,accurately and in a large range,it will provide an important reference for the rational planning and vibration reduction design of rail transit lines.The purpose of this paper is to establish a fast and accurate method for regional vibration prediction,which is based on the database and does not need to carry out complicated numerical simulation or a large number of field measurements.but only using the existing soil drilling data.The main research work and results achieved in this article are as follows:(1)Based on the design and development of Python + Django and My SQL database,a database is established,including soil layer transfer function,vehicle rail vibration excitation force and frequency-domain correction function of tunnel structure.(2)According to the principle of k NN classification algorithm,an algorithm program for finding the optimal transfer function is written.The binary index(s,r)is used to analyze and evaluate the accuracy of the optimal transfer function,and evaluation results meet requirements.(3)Developed a website using the interactive functions of Python&Django's front-end,back-end and My SQL database.Simply submit the soil layer parameters at the front-end of the website page,then the back-end server can automatically complete the search for the optimal soil layer transfer function,and combine with the rail vibration excitation force database data to realize the rapid prediction of the free-field ground surface vibration in the time and frequency-domain.The prediction result data can be returned to the front-end webpage for display.(4)The numerical calculation method was used to analyze the difference between the ground surface vibration response of the tunnel with and without the tunnel conditions,and a correction function for the vibration response of the free-field ground surface under different burial depth conditions was obtained,thereby obtaining a more accurate prediction of the ground surface response caused by the subway train.Takingthe section of Jiulongshan Station-Dajiaoting Station on Line 9 of Beijing Metro as the background,regional environmental vibrations can be quickly predicted.