地基土层剪切模量的随机分布及地面振动传递函数的区间估计  

Random distribution of shear modulus of soils and interval estimation of ground vibration transfer function

作　　者：曹艳梅[1] 李东伟 李喆[1] CAO Yanmei;LI Dongwei;LI Zhe(School of Civil Engineering,Beijing Jiaotong University,Beijing 100044,China)

机构地区：[1]北京交通大学土木建筑工程学院,北京100044

出　　处：《岩石力学与工程学报》2021年第5期1022-1031,共10页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助项目(51978043)。

摘　　要：为探究非确定性土参数的概率分布模型及其对场地土随机振动的影响,通过多通道面波测试技术(MASW),结合频率–波数法获得了场地土的频散图像,建立剪切模量随土层深度变化的先验概率分布模型,进而依据贝叶斯理论及蒙特卡洛–马尔科夫链–Metropolis-Hastings算法得到了非确定性土参数的后验概率分布模型,并对其收敛性和独立性进行了验证。将地基土剪切模量的后验概率分布模型和地面振动随机响应的核密度估计相结合,提出对振动传递函数进行区间估计的一种有效方法,得到具有一定置信度的置信区间,并与确定性土参数反演的传统振动预测方法以及试验数据进行比较。研究结果表明,后验剪切模量在空间深度上具有明显的随机性,而非确定性的剪切模量分布会对环境振动的预测和评价产生较大影响,基于非确定性土参数概率分布模型进行振动区间估计的方法具有较大的工程应用价值。In order to explore the probabilistic distribution model of non-deterministic parameters of soils and its effect on random vibration of the site,the dispersion image of the site soil is obtained by multi-channel analysis of surface wave(MASW)testing combined with frequency-wavenumber method,and a prior probability model of the shear modulus of the soil varying with depth is established. Based on Bayesian theory and Monte Carlo Markov Chain-Metropolis-Hastings algorithm,a posterior probability model of non-deterministic parameters of the soil is achieved and its convergence and independence are validated respectively. Finally,a new method for predicting the vibration transfer function by means of the confidence interval with certain confidence level is proposed,in which the validated posterior probability model is combined with the kernel density estimation of the random response of the ground vibration. The proposed non-deterministic prediction method is also compared with the experiment results and the traditional deterministic vibration prediction methods. The results show that the posterior shear modulus has obvious randomness in spatial depth, and the non-deterministic shear modulus distribution has a greater impact on the prediction and evaluation of environmental vibration. The vibration interval estimation obtained from the probability model of the non-deterministic parameters of soils has great engineering application value.

关 键 词：土力学 MASW 剪切模量 后验概率分布模型 贝叶斯理论 MCMC-MH算法 区间估计 振动传递 

分 类 号：TU43[建筑科学—岩土工程]