层状地基分界面对于空沟隔振效果的影响分析

Effect of Interface in Layered Foundation on the Open Trench Vibration Isolation

摘要:

为研究层状地基的分界面对于空沟隔振效果的影响，采用模型试验，选取三种不同深度的空沟，分别为小于分界面深度和等于分界面深度以及超过分界面深度的三种深度，分析在改变空沟宽度、空沟位置（固定振源即传感器位置，仅改变空沟所处位置）以及激振频率时对三种深度空沟隔振效果的影响。结果表明：当宽度和激振频率发生改变时，深度等于土层分界面处深度的空沟隔振效果变化最不明显；当宽度和空沟位置发生改变时，沟深小于分界面深度的空沟受到的影响最为明显；在激振频率的改变下时，沟深大于土层分界面深度的空沟所受影响最大；当固定其余参数，逐渐增加空沟深度时，深度在变化到分界面处时会有A_r值发生增加现象，该现象受到激振频率影响，激振频率越低，则上升幅度越大，低频的上升区间也最长，即A_r值从出现上升趋势至恢复减小趋势的距离为上升区间。综上结论，在选择隔振沟时应注重上述因素的影响，合理设计隔振沟，使其达到最佳隔振效果。

Abstract:

To study the influence of interface in layered foundation on the vibration isolation effect of open trench, three kinds of open trenches with different depths were selected by model test, i.e., less than the interface depth, equal to the interface depth, and more than the interface depth. Then, by changing the width and position of open trench and the excitation frequency, the influences on the vibration isolation effect of open trenches with three different depths were analyzed. The results showed that: when changing the width and excitation frequency, the change of vibration isolation effect of the open trench with depth equal to the soil interface is the least obvious; when changing the width and position of the open trench, the vibration isolation effect of the open trench with depth less than the interface is most affected; when changing the excitation frequency, the effect of the open trench with depth greater than the soil interface is most affected. If the remaining parameters are fixed and the trench depth is gradually increased, the A_r value will increase when the depth reaches the interface, which is affected by the excitation frequency. The lower the excitation frequency is, the greater the rising range is, and the rising range of low frequency is the longest. In conclusion, when choosing the vibration isolation trench, we should pay attention to the influence of above factors and reasonably design the vibration isolation trench to achieve the best vibration isolation effect.