场地土动力特性识别方法对比

结合自由场地土振动台试验，对比了随机子空间迭代（SSI）方法、经验模式分解结合希尔伯特变换（EMD＋HT）方法和频域分解（FDD）方法识别场地土卓越频率、阻尼比的适用性，以及不同激励类型、不同土层深度和大阻尼比情况对识别精度的影响。结果表明：对于随机激励，当阻尼比较小时，上述3种方法均能准确识别出场地土卓越频率；而大震时土体卓越频率、阻尼比与振动过程耦合，此时经验模式分解结合希尔伯特变换方法可以给出合理的识别结果。

Comparison of Soil Dynamic Property Identification Method

Combining free soil shaking table test, the predominant frequency of silty clay and its damping ratio used in series of shaking table test were identified by three commonly used methods, i. e. the stochastic subspace identification （SSI） method, frequency domain decomposition （FDD） method and empirical mode decomposition plus Hilbert transform （EMD＋ HT） method. The applicabilities of the three methods were verified and identification results were discussed in items of effect of input type, different soil depths and selection of calculating parameters concerning large damping ratio cases. The results show that the three methods are applicable for random excitation and small damping ratio cases; only empirical mode decomposition plus Hilbert transform method can produce reasonable results when soil predominant frequency and damping ratios are coupled with vibration process or subjected to strong earthquake.