| Rail transit has gradually become the main mode of transportation due to its safety,high efficiency,and strong practicability,meeting people's growing daily needs.However,the vibration generated by rail transit not only harms surrounding buildings,but also affects the human health of surrounding residents.Therefore,reducing the impact of the vibration generated by rail transit on the surrounding environment has become the primary task of my country's current railway development.In this paper,a combination of theoretical analysis,field test and numerical simulation is used to systematically analyze the impact of the track train on the surrounding environment and the analysis of the vibration isolation effect of the trapezoidal ditch vibration isolation barrier.Established the "track-foundation" coupling model and "vehicle-track-foundation" respectively to study the trapezoidal trench in two-dimensional point load and three-dimensional line load and simulate the vibration isolation effect of trains on uneven track.The following conclusions are drawn through experiments :(1)The characteristics and effects of profile-shaped gully were studied through site test,and a 1:1 model was established by ABABQUS finite element method according to site test.Field test results and numerical simulation test results were compared and analyzed to verify the reliability and practicability of numerical simulation test.(2)The two-dimensional finite element test was established.According to the vibration analysis of different frequencies in the subgrade,it was obtained that the low-frequency 10 Hz vibration wave had stronger propagation ability in the foundation.At the same time,by setting special-shaped trench on both sides of the subgrade,under the action of 10 Hz point vibration sources,the model parameters,such as horizontal width of the slope of special-shaped trench and the depth of the trench,as well as the vibration source distance,all have an impact on the vibration isolation effect of special-shaped trench.(3)Through the method of numerical model,the three-dimensional finite element model is established,Experimental study on the vibration isolation effect under the condition of line load when the geometrical parameters of special-shaped gully change the horizontal width of slope gully depth gully width at the bottom Filler attribute vibration source distance.It is found that increasing the horizontal width of the slope and the trench depth can enhance the vibration isolation effect of special-shaped trench,but the vibration isolation effect decreases with the increase of the vibration source distance.The bottom gully width has no obvious effect on the vibration isolation effect of special-shaped gully.Both empty gully and filled gully can produce the vibration isolation effect of special-shaped gully,but the vibration isolation effect of empty gully is better.(4)Referring to the power spectrum of America's six grade track irregularity,a three-dimensional irregularity track model is established by means of numerical simulation to simulate the actual running process of trains.The influence of the length of the gully and the distance of the gully on the vibration isolation effect of special-shaped gully is analyzed.The results show that the vibration isolation effect of special-shaped gully is enhanced with the increase of train speed under the condition of different train speed;By studying the discontinuous special-shaped trench spacing S,it is found that with the increase of the gap spacing S,the deep foundation and surface vibration isolation effect after the discontinuous special-shaped trench barrier presents a trend of first decreasing and then increasing;With the increase of the length of the irregular trench,the isolation effect of the irregular trench in the deep foundation and the surface of the research area is enhanced,The isoline areas of all Ar values gradually form a relatively unified whole,making the isolation effect better and more obvious. |
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