地层中存在裂缝情况下的瑞利导波频散特征  

DISPERSION CURVES OF RAYLEIGH WAVE IN FISSURED STRATA

作　　者：杨天春[1] 杨立新 郑京杰 

机构地区：[1]湖南科技大学土木工程学院,湖南湘潭411201 [2]湖南省交通建设质量监督站,湖南长沙410001

出　　处：《物探与化探》2007年第4期361-364,共4页Geophysical and Geochemical Exploration

基　　金：国家自然科学基金(50378034)资助;湖南省教育厅资助科研项目(06B030)

摘　　要：弹性波穿过裂缝时的情况比较复杂,目前还没有比较好的理论来描述这一问题。作者根据前人的研究经验,采用液体层来替代地层的裂缝结构,由此研究地层中存在裂缝情况下的瑞利导波频散特性。根据模拟计算结果发现,当地层中存在裂缝时,其瑞利导波频散曲线的基阶模式会出现截止或截断现象。这时,在实际应用过程中,在某些频率段接收到的信号为瑞利导波的高阶模式或泄漏波模式,接收信号中存在模式间的跳跃,实际频散曲线就会出现"之"字形现象。The traversing of elastic waves through fissures is very complex, and there is not an appropriate theory to describe this problem. Based on previous workers＇experience, the authors studied dispersive characteristics of Rayleigh waves by using liquid as a substitute for the fissure. Simulation results show that, when there exists a fissure in the foundation, the first mode curve has a cut-off frequency or assumes an interceptive phenomenon. Consequently, the dispersion curves obtained in the investigation consist of multimode guided waves, and there are leaky mode waves at times. The zigzag dispersion curves will occur because of jumping among modes.

关 键 词：瑞利波 频散 导波模式 “之”字形频散 裂缝 

分 类 号：P631.4[天文地球—地质矿产勘探]