复杂介质中瑞雷面波最大模频散特征分析及实验研究

Experimental study and analysis on dispersion curve features of Rayleigh surface wave with maximum mode in complex media

目前,对瑞雷面波的正反演理论、基阶频散特征的应用研究等都是基于水平层状介质。但实际地层大多为横向不均匀的复杂介质,如城市地铁隧道、地下停车场等城市地下空间。近几年多道面波分析(MASW)技术在国内外已经有了许多应用实例,但该技术在复杂介质中的应用效果并不理想,同时还缺少大量的理论和实验研究。本文通过对比水平层状介质和复杂介质中瑞雷面波能量分布的特征变化,在此基础上,将最大模频散(凡友华提出)的概念和提取方法应用到复杂介质的模拟数据和实际数据中。实验研究表明:复杂介质的两种数据的最大模频散曲线特征具有可对比性。复杂介质的最大模频散曲线包含了各阶模信息,最大模频散是多阶瑞雷波综合叠加的结果,能更精确地反映实际地层结构。本次实验成果在实际的复杂介质探测中具有一定的现实和指导意义。

At present,the forward and inversion theory of Rayleigh wave and the applied research on fundamental mode dispersion characteristics are based on the horizontal layered media,but the actual media are the lateral heterogeneous complex media such as the urban underground spaces for urban subway tunnel and underground parking.In recent years the multichannel analysis of surface wave technology（MASW） has be used in engineering practice at home and abroad,but the effect of application is not ideal in complex media and it lacks of the numerous theoretical and experimental research.The variations of Rayleigh wave energy distribution characteristics in horizontal layered media and in complex media are compared,and the maximum mode dispersion concept（Fan Youhua presented）and the extracting method are applied to the simulated data and the actual data from complex media.The results show that the maximum mode dispersion curves of the two kinds of data are of contradistinctive features,which contain the multimodal information.The characteristics of the curves are the comprehensive results of multimodal Rayleigh wave,which could more accurately reflect the real stratum structure.The experimental results are of certain practical and guiding significance in the actual detection of complex media.