Prediction And Control Study On Environmental Vibration Of Underground Lines In High-speed Railway

Currently,the world’s largest high-speed railway network has been built in China,which has the fastest growing speed,the longest operating mileage all over the world.By the end of 2019,the operating mileage of high-speed railway of China has reached 35,000 km,which is more than 2/3 of the total operating mileage of the global high-speed rail.In spite of so many advantages of high-speed railway,the vibration and noise as well as other related environmental issues induced by the operation of high-speed railway still attracted the attention of general public.In the high-speed railway entering and leaving the city section,the use of underground line laying has gradually become a trend.At this time,in order to reduce the division of urban built-up areas,reduce the amount of project demolition and decrease ground noise pollution.Thus,the environmental vibration problem brought by the high-speed railway underground line has received more and more attention.However,the theoretical and measured research on its vibration source characteristics,propagation laws and vibration response of adjacent buildings are insufficient.The reliable prediction and control methods to guide environmental assessment and engineering design are insufficient due to the small number of high-speed railways underground line.Because of the difference between the engineering technical standards for vehicles,lines,tracks,tunnels of high-speed railways and those of ordinary speed railways,urban rail transits,which leads to great difference in the environmental vibration characteristics,the existing environmental vibration prediction and control methods cannot be directly adopted.The high-speed railway underground line has been forced to reduce the design speed in recent years.For example,the design speed of the Jing-Zhang high-speed railway underground line section was reduced to 120km/h,the Shijiazhuang section of the Jing-Guang high-speed railway,the Futian section of the Guang-Shen-Hong Kong high-speed railway,and the Qingdao section of Ji-Qing railway has dropped to less than 200km/h,which has seriously affected the operational efficiency of the high-speed rail.Therefore,it is urgent to study the environmental vibration prediction and control methods for high-speed railway underground lines.Based on wheel-rail interaction dynamics and vibration propagation theory,the generation mechanism,propagation law,influencing factors and control methods of environmental vibration of high-speed railway underground line were studied by combining with field test,numerical simulation and statistical analysis method in this paper.(1)A high-speed train-track-tunnel-soil-building coupled theoretical model aimed to study the vibration level,spectrum features,characteristics of environmental vibration changing rapidly with speed and transmission characteristics of environmental vibration induced by high-speed railway underground line was established.The time/frequency domain analysis of the environmental vibration induced by high-speed railway underground line was realized based on wheel-rail interaction dynamics and structural dynamics by using multi-body dynamics and finite element method.The model can consider the influence of detailed structures such as trains,tracks,tunnels,soils and buildings systematically,and vehicle-rail-tunnel-soil-building interaction.The new model has been innovated in terms of systematization,refinement,comprehensiveness and applicability.It can reliably represent the environmental vibration level and the distribution vibration characteristics of high-speed railway in time and frequency domain.(2)The typical section of the high-speed railway underground line was selected to carry out systematic environmental vibration test,and the new theoretical model of environmental vibration was verified.The paper designs a test of key propagation path for environmental vibration,and selects the typical sections of high-speed railway(the underground lines of Guan-Hui intercity,Fo-Zhao intercity and Guang-Shen-Hong Kong high-speed Railway)to test environmental vibration.The time/frequency domain propagation characteristics of the environmental vibration in the vibration source,the propagation path and the vibration body were obtained through the dynamic test in the tunnel,the surface and the adjacent buildings during the passage of trains.Based on the measured data,the theoretical analysis model was verified.(3)An empirical prediction model of environmental vibration for high-speed railway underground lines was established based on the transfer chain loss method,considering different vibration sources,vibration propagation paths and vibration receptors.Based on the established high-speed train-track-tunnel-soil-building space coupling dynamics model and measured data,the influence of the key factors such as vehicle type,track type,tunnel type,railway depth and distance,and building structure type,on the generation,propagation and attenuation laws of environmental vibration were analyzed.Based on statistical Analysis of theoretical calculation results and experimental results,and the transmission chain loss method,an empirical prediction model of environmental vibration for high-speed railway underground lines was established.(4)The control method of environmental vibration for high-speed railway underground line was proposed,and the vibration control method in vibration source and propagation path suitable for high-speed railway underground line was studied.The vibration control method of changing the parameters of the track structure and tunnel structure at the vibration source and the vibration control method of setting the vibration isolation piles in the propagation path were studied.