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基于隧道地震波场二维数值模拟是研究隧道超前探测过程中地震波传播规律的基础,目前关于这方面的研究均建立在隧道侧壁观测系统的基础上,并且把隧道空间作为与周围地层具有同样弹性参数的均匀介质考虑,因此不能实现全波场模拟,与实际存在差异。基于实际隧道空间,建立了更加接近实际的隧道地质模型,实现了隧道空间的二维全波场模拟。通过二维全波场模拟及实例结果对比分析表明:①采用空间四阶时间二阶交错网格有限差分法能有效实现基于隧道空气介质的二维全波场模拟;②当地质界面倾角为90°时,掌子面附近激发的共激发点观测系统比侧壁的共接收点观测系统更有利于反射波的获取;③随着地质界面倾角的减小,界面同侧激发和接收的反射波能量增强;④对于局部地质体和大倾角地质界面,掌子面附近激发横波能量强于纵波,有利于横波成像。
Based on the two-dimensional numerical simulation of tunnel seismic wave fields, it is the basis of studying the propagation law of seismic waves during the advanced detection of tunnels. At present, the research on this area is based on the tunnel side-wall observation system and takes the tunnel space as the same elasticity as the surrounding strata Parameter uniform medium considerations, it can not be achieved full-wave field simulation, and the actual differences. Based on the actual tunnel space, a more realistic tunnel geological model is established and a two-dimensional full-wavefield simulation of the tunnel space is realized. Through two-dimensional full-wave field simulation and comparative analysis of case results, it is shown that: (1) the second-order staggered-grid finite difference method can effectively simulate two-dimensional full-wave field based on tunnel air medium; (2) °, the co-excitation point observation system excited near the face of the face is more conducive to the acquisition of the reflected wave than the common receiving point observation system of the side wall; ③ With the decrease of the dip of the geological interface, the reflected waves Energy enhancement; ④ For local geology and geologic interface with large dip angle, the shear wave energy near the face of the palm is stronger than that of the longitudinal wave, which is in favor of transverse wave imaging.