城市地铁典型隔振措施隔振效果的模型试验研究

Research on the model test on vibration isolation effect of typical vibration isolation measures in urban subway

为了研究振动波的空间传递规律和不同类型隔振屏障的性能,文中通过5组模型试验得到了不同频率的振动波在红黏土地基中的空间传递规律,同时采用振动加速度级定量评价空沟、沙子填充屏障、碎石填充屏障和地下连续墙等典型连续隔振屏障的隔振效果。结果表明:(1)无隔振措施时,在水平方向上,加速度级随着距振源水平距离的增加而减小。在竖直方向上,模型顶部加速度级略大于模型底部,随着距振源水平距离的增加,加速度级变化量值逐渐减小。(2)同一测点处,随着激振频率的增加,土体加速度级呈现衰减趋势。(3)各种隔振措施中,空沟隔振效果最好,沙子填充屏障隔振效果最差。具体为:空沟>地下连续墙>碎石填充屏障>沙子填充屏障。(4)振动波在遇到隔振屏障时会发生反射,从而加剧屏障前侧前土体振动。不同隔振屏障对振动波反射的剧烈程度为:碎石填充屏障>地下连续墙>空沟>沙子填充屏障。

In order to study the spatial transmission law of vibration waves and the performance of different types of vibration isolation barriers,five sets of model tests were carried out in this paper to obtain the spatial transmission law of vibration waves of different frequencies in red clay foundation.The vibration acceleration levels were used to quantitatively evaluate the vibration isolation effects of typical continuous vibration barriers such as empty trench,sand-filled trench,gravel-filled trench,and concrete wall.The results show that without vibration isolation,the acceleration level decreases with the increase of horizontal distance from the vibration source in the horizontal direction.In the vertical direction,the acceleration level at the top of the model is slightly larger than that at the bottom of the model,and the variation of the acceleration level decreases with the increase of the horizontal distance from the source.At the same measurement point,with the increase of excitation frequency,the vibration acceleration level of soil shows a decaying trend.Various vibration isolation measures,empty trench vibration isolation effect is the best,and sand-filled trench vibration isolation effect is the worst.The order for the performance of the isolation barrier was as follows,empty trench(best),concrete wall,gravel-filled trench,and sand-filled trench(worst).As vibration wave would reflect at the boundary of isolation barrier,this led to the enhancement of soil vibration at the front of isolation barrier.The degree of enhancement of isolation barrier was as follows,gravel-filled trench(strongest),concrete wall,empty trench,and sand-filled trench(smallest).