基于土体参数估算土体振动衰减系数的方法研究

Research on the Method of Estimating Vibration Attenuation Coefficient of Soil Based on Soil Parameters

根据现有规范中的振动衰减公式,建立α_(0)与地基土动力参数之间的公式化联系,通过地基土本身的参数来唯一确定α_(0)。采用理论推导,现场试验以及和已有文献比对的方法,验证了本文所提方法的有效性和准确性,研究结果表明:(1)衰减公式中的几何衰减系数ζ;只会影响振动响应的幅值,但是对于传递路径上两点之间的振动传递比影响不大;(2)基于地基土的动力特性参数表征土体衰减系数具有较高的可靠性;(3)振动信号从低频到高频中,每一频率下参与土体振动的有效深度不一致,低频几乎影响各层土体,高频振动信号主要影响范围在表面。

A formulaic connection between α_(0) and the dynamic parameters of the foundation soil was established according to the vibration attenuation formula in the existing code, and α_(0) was uniquely determined by the parameters of the foundation soil itself. The effectiveness and accuracy of the proposed method were verified by the method of theoretical derivation, field test and the comparison with the existing literature. The research results show that:(1) The amplitude of the vibration response is influenced greatly by the geometric attenuation coefficient ζ;. However, the influence induced by ζ;to the transfer ratio between the two points on the transmission path can be neglected;(2) the soil attenuation coefficient calculated by the dynamic characteristics of soil is of higher reliability;(3) the effective vibration depth of the soil varies with the frequencies, and the low frequency vibration almost affects each layer of the soil, and the high frequency vibration signal mainly affects the top layer of the soil.