层状地基环形沟隔振效果影响因素分析

Factors influencing the vibration isolation effect of annular ditches in layered foundation

摘要:

为探究层状地基环形沟隔振中几何参数对其隔振效果的影响规律，文章采用振幅衰减比A_r值进行评价分析，并定义沟后A_r≤0.4区域为有效隔振区域，通过改变环形沟的几何参数，得到其对有效隔振区域影响变化规律，从而确定环形沟不同几何参数对其隔振效果的影响。结果表明：层状地基土中环形沟深度位于土层分界面附近时，环形沟隔振效果相对较弱；当宽度参数在0.01~0.35之间不断增大时，有效隔振区域占比变化幅度仅为4.8%，即环形沟宽度变化对环形沟隔振效果影响较小；随着环形沟弧长的增加，有效隔振区域面积的扩大速率减缓，弧长参数达到2.20以后，隔振效果趋于稳定；振源与环形沟之间及环形沟末端位置区域存在振动放大区。

Abstract:

To explore the influence of geometric parameters of the annular trench in layered foundation on its vibration isolation effect, the amplitude attenuation ratio (A_r value) was adopted for evaluation and analysis in this paper. The area behind trench with A_r value ≤ 0.4 was defined as the effective vibration isolation area. The geometric parameters of annular groove were changed to obtain its influence law on the effective vibration isolation area, so as to determine the influence of different geometric parameters on the vibration isolation effect of annular groove. The results showed that the vibration isolation effect of annular groove is relatively weak when it is near the interface of soil layer. When the width increases from 0.01 to 0.35, the proportion of effective vibration isolation area only changes by 4.8%, namely that the change of width has little influence on the vibration isolation effect. As the arc length of the annular groove increases, the expansion rate of the effective vibration isolation area slows down. After the arc length reaches 2.20, the vibration isolation effect tends to be stable. There are vibration amplification zones at the end of the annular groove and between the vibration source and the groove.