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一、前言地面脉动通常是指几微米以下的微小振动,一般认为它是随机振源影响下土层的振动反应,因此是一个随机过程,其周期特征在某种意义上反映了土层的动力特性。地面脉动的观测结果通常采用周期——频度谱(也称金井谱)及富化谱等方法加以分析。由于地面脉动可以看作是一个平稳随机过程,因此可用自相关函数、互相关函数、自功率谱密度函数等统计特性来描述其振动性状。本文用给定场地土上地面脉动的功率谱形状,来表示不同场地的动态特性。以往的观测结果表明,不同场地上的地面脉动卓越周期值在0.20～0.80秒者占绝大多数。可以认为,某场地上的地面运动周期
I. INTRODUCTION Ground pulsation usually refers to micro-vibrations below a few microns. It is generally considered to be a vibrational response of a soil layer under the influence of a random vibration source. Therefore, it is a random process whose periodic characteristics reflect the dynamics of the soil in a certain sense. characteristic. Ground pulsation observations are usually analyzed using periodicity-frequency spectra (also known as goldwell spectra) and enriched spectra. Since the ground pulsation can be regarded as a stationary random process, the statistical properties such as autocorrelation function, cross-correlation function, and self-power spectral density function can be used to describe its vibration properties. This paper uses the power spectrum shape of ground pulsations on the given site to represent the dynamic characteristics of different sites. The previous observations show that the predominant period of ground pulsation on different sites accounts for most of the 0.20-0.80 seconds. It can be considered that the ground motion cycle on a field