Study On The Propagation Laws And Isolation Measures Of Railway-Induced Site Vibration

In recent years, The sixth massive speed-up of China's existing railways is planned to carry out,the construction of dedicated passenger railway line and high-speed railway network are also accelerating,train speed is increasing step by step.In the process of achieving railroad great-leap-forward development,the orginal commom speed railroad cannot meet the current and future demand for railway construction,so it is urgent to study the railroad environmental vibration with the main features of high-speed.For typical zones of the Changsha-Zhuzhou-Xiantan intercity rail, the Beijing-tianjin intercity rail, the Beijing-Guangzhou line, the Shanghai-Hangzhou line, Beijing-Shanghai line and the Hefei-Wuhan intercity railway line, a great many of tests are carried out on propagation and attenuation of environmental vibration, so that we can evaluate and forecast the environmental vibration produced by railroad traffic according to practice,then put forward reasonable isolation vibration measures. For low frequency vibration, adopt different isolation vibration measures(continual wall, open trench, WIB and H-WIB) to reduce vibration, discuss barrier parameters for the effects of isolation vibration, get useful conclusions and provide a theoretical basis for engineering.The main research productions are as follows:1. Collect and collate existing research results systematically, discuss the theories of wave propagation and methods about environmental vibration.2. Field environmental vibration test, operational analog monitor, calculation and evaluation are done, for the Changsha-Zhuzhou-Xiantan intercity rail maybe has vibrational effect on laboratory buildings and residential quarters of National University of Defense Technology, according to the impact and the extent of assessment results corresponding isolation vibration measures are taken, then provide scientific evidence for the design of the Changsha-Zhuzhou-Xiantan intercity rail.3. Testing on typical zones of the Beijing-tianjin intercity rail, the Hefei-Wuhan intercity railway line, the Shanghai-Hangzhou line and the Beijing-Guangzhou line, get vibrational source strength and spectral characteristics, research on the propagation and attenuation of environmental vibration, compare test source strength with "environmental impact assessment of railway construction project:value and govern on noise and vibration source stength" and provide a reference for valueing of vibration source stength.4. Using simulated load combined with high, medium and low frequency, research on propagation law of ground vibration induced by subway with finite differential method and isolation vibration of low-frequency vibration produced by subway and high speed railway, introducing new isolation vibration measures(entity-WIB, box-WIB and H-WIB), compared with traditional methods(open trench and continual wall), results show for low-frequency ground vibration induced by subway and high speed railway, H-WIB can reduce vibration level of ground surface at least 6-12dB. open trench also has better isolation vibration effect, however, construction is diffcult and operation is not high. H-WIB is better than entity-WIB,box-WIB and other kinds of isolation vibration measures in aspects of from isolation vibration effect, economy and operation, specially for low frequency vibration within lOHz, H-WIB is superior to other kinds of isolation vibration measures.5. For low frequency vibration induced by high speed railway, a new simulated load which is converting actual observed acceleration of bridge pier to dynamic load acting in the surface of the soil is introduced to carry out numerical calculation of isolation vibration, results show that H-WIB still has better isolation vibration effect than other measures and reduce vibration amplitude above 70% when changing simulated load. For low frequency vibration within 10Hz, H-WIB is still far better than other kinds of isolation vibration measures...