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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 research on the positive and negative inversion theory of Rayleigh wave and the application of the fundamental dispersion characteristics are all based on horizontal layered media. However, most of the actual strata are inhomogeneous complex media, such as urban subway tunnels, underground parking spaces and other urban underground space. In recent years, there are many application examples of MASW technology at home and abroad. However, the application of this technology in complex media is not satisfactory, and a large number of theoretical and experimental studies are lacking. In this paper, by comparing the characteristic changes of Rayleigh wave surface energy distribution in horizontal layered media and complex media, based on this, the concept of maximum modular dispersion (proposed by Van Fanhua) and the extraction method are applied to the simulation data of complex media Actual data. Experimental results show that the maximum mode dispersion curve characteristics of two kinds of data in complex medium are comparable. The maximum modal dispersion curve of complex medium contains the information of each order mode. The maximum mode dispersion is the result of multi-order Rayleigh wave superposition, which can more accurately reflect the actual formation structure. The experimental results in the actual detection of complex media has a certain degree of reality and guiding significance.