【作者】 王旭；

【导师】 刘争平；

【作者基本信息】 西南交通大学 ， 建筑与土木工程专业（专业学位）， 2017， 硕士

【摘要】 波场快照能够全面清晰直观地显示出地震波在介质中传波的时空图像,对于认识和研究复杂条件下构造、物性和岩性等多种地质因素与地震波之间的响应特征(波场特性)具有极大帮助,而波场特性是地震勘探领域内解释资料时必不可少的依据。尽管由于物理模拟方法技术的限制,数值模拟目前仍是获取地震波时空传播的波场快照的主要方法,但物理模拟在地震波场的认识和研究中的重要性和不可替代性一直促使地球物理学者发展通过物理模拟获取波场快照的方法。本文从二维地震模型的理论出发,结合地震波第一菲涅尔带半径理论(横向分辨率)以及观测条件限制(激发传感器尺寸),对实验中所用二维模型的厚度进行研究,然后结合超声地震物理实验的基础理论,运用基于虚拟仪器技术搭建的超声物理实验观测系统,以及设计的针对波场快照数据采集的观测方案,对制作的二维均匀介质模型和二维横向非均匀介质模型进行实验,并将测得的实验数据应用编制的数据处理程序进行处理,最后利用处理后的数据绘制二维波场快照,并提取使用本方法测得的近自由表面记录的瑞利面波的频散特征,与相应数值模拟结果进行对比分析,来验证本实验方法的可行性和可信度。最终得到了均匀半空间和横向非均匀半空间模型的二维波场快照。以两种模型的实验观测和处理后数据绘制的波场快照以及近自由表面记录的瑞利面波的频散特征,与对应的二维数值模拟的结果对比,二者具有很好的一致性,验证了超声物理技术模拟波场快照方法的可行性和可信性。研究结果表明,本文提出的物理模拟方法具有直观地揭示二维复杂介质中全波震像的时空响应特征的优势。更多还原

【Abstract】 The wave-field snapshots can clearly and visually show the temporal and spatial images of the seismic waves in the medium,and the response characteristics(wave field characteristics)between the geological factors such as tectonics,physical properties and lithology under complex conditions is of a great help,and wave field characteristics in the field of seismic exploration is essential to explain the basis of information.Although the numerical simulation is still the main method to obtain the time-space wave propagation of seismic wave due to the limitation of the physical simulation method,the importance and irreplaceability of the physical simulation in the understanding and research of the seismic wave field have been to promote the development of geophysicists A method of obtaining a wavefront snapshot by physical simulation.Based on the theory of two-dimensional seismic model,the thickness of the two-dimensional model used in the experiment is studied by combining the first Fresnel zone radius theory(transverse resolution)and the observation condition(excitation sensor size).Then based on the basic theory of seismic physics experiment,the ultrasonic physical experiment observation system based on virtual instrument technology is used to construct the two-dimensional homogeneous media model and the two-dimensional transverse heterogeneous media model by using the designed observation scheme for wave field snapshot data acquisition.And the measured experimental data were processed by the prepared data processing program.Finally,the two-dimensional wavefield snapshot was drawn with the processed data and the frequency of the Rayleigh surface wave recorded by the near-free surface was measured by the method.And the corresponding numerical simulation results were compared and analyzed to verify the feasibility and credibility of the experimental method.Finally,a two-dimensional wavefield snapshot of the uniform half-space and transverse non-uniform half-space model is obtained.The wave-field snapshots and the near-free surface recorded Rayleigh wave characteristics are compared with the results of the corresponding two-dimensional numerical simulation,and the two are well consistent with the experimental observation and processing of the two models,which verifies the feasibility and credibility of the ultrasonic wave method.The results show that the proposed physical simulation method has the advantage of visually revealing the spatiotemporal response characteristics of the whole-wave image in two-dimensional complex media.更多还原