Study On The Propagation Laws Of Subway-induced Vibration And Isolation Or Reduction Methods Of Building Vibration

With the rapid development of subway, some shortcomings are also been found. One of them is vibration, which is called a social effects of pollution and should be controlled. But our knowledge about subway vibration is limited, especially about vibration exciting force, vibration propagation in soil, vibration isolation or reduction of building and so on. So the dissertation focuses on the subway vibration problem and has obtained some valuable result.First, the vibration propagation characteristic in layered soil has been investigated theoretically, which are concerned with body-wave, surface-wave and wave in saturated clay. Meanwhile wave reflection & transmission and reduction law are also been studied. Second, the subway vibration is measured in field and time history of acceleration are transform by FFT method, which make us to get the propagation law and vibration level. The result tell us that vertical vibration is much violent than horizontal one. Vertical vibration could be only taken into account when we study the environment problem induced by underground. The excellent frequency of vertical vibration above the tunnel is 40-80Hz. The component of greater frequency vibration attenuates rapid than smaller one. When distance to tunnel is near 30m, the 60Hz frequency vibration is as stronger as 10Hz one. The vibration level is satisfied national code when distance to tunnel is within 5m. Third, Besides getting a more reasonable exciting force by improving the analysis model, the thesis successfully imitate the vibration propagation by means of FEM, in which we have discussed many questions such as model size, element size, damping-ratio choice and boundary conditions. It tells us that element size should be 1/12-1/8 of reyliegh wave length and the choice of damping ratio should relate to the frequency of exciting force. The simulate result is consistent with the field test. Fourth, the barrier measure is investigated to control the vibration level. The depth, thickness and material of barrier are discussed as parameters. The control effect is much sensitive to material than it to thickness and depth. Concrete barrier to underground vibration is not sound. Fifth,...