Research On The Vibration Propagation And Continuous Reductions Of Vibration Isolation In High-Speed Railway Subgrade

High-speed railway is a low energy consumption and high efficiency of transportation method,which has played a strong role in promoting the rapid development of the national economy.But as the speed of the train operation,the improvement of traffic density and the encryption of the railway network,environmental vibration caused by high-speed railway to highlight gradually,has brought many negative effects to people's production and living.Currently in the measures of reducing high-speed rail vibration isolation,setting vibration isolation barriers is the most common method.In the measure of setting vibration isolation barriers,it is the continuous reduction of vibration isolation barriers such as open trench and In-filled ditch that has widely been used in practical engineering because of its convenient construction and the better effect of vibration isolation.Based on the two methods of reduced scale model test and finite element numerical analysis,this text analyzes the effect of vibration isolation about open trench different materials in-filled ditch as well as the factors that affect the effect of vibration isolation.Reaching the following conclusions:(1)After carrying the measure ofopen trench vibration isolation out,the back soil of open trench within a certain distance will form a vibration impact area.The vibration in the area of influence and strength are greatly influenced by open trench depth,less affected by the width.The average acceleration value of back soil of open trench can be reduced by 30%~80%.(2)The depth of open trench impacts clearly the effect of vibration reduction,but the growth rate of the effect of vibration reduction becomes slow down and tends to stable when the open trench is increased to a certain depth;Comprehensive calculation results and the ease of open trench construction,suggested that the depth is set to 4~5 m.the width of open trench has less effect on vibration reduction of its back soil,and is likely to increase the average acceleration value,suggested that the width is set less than 1 m.(3)Under the same condition of train load amplitude,the effect of vibration reduction is enhanced with the increase of frequency,and the effect of vibration reduction becomes stable when the frenquency is increased to a certain extent.(4)Open trench is best to reduce vibration isolation,followed by the rubber particles-filled ditch and gravel-filled ditch,sand-filled ditch reduction of vibration isolation is the poorest.The effect of vibration isolation on different working conditions is different in the location closed in-filled and the effect is approaching with the increase of distance.(5)In addition to the rubber particles filled trench,the soil vibration before the open trench,sand-filled ditch and gravel-filled ditch all have different degree of intensified,during the process of design and construction of high-speed railway continuous vibration isolation barriers,the influence of the barrierstothe high-speed railway foundation should be taken into account.