F-K变换在隧道反射地震预报波场分离中的数值模拟研究

发布时间：2018-03-06 05:27

本文选题：隧道地震超前预报　切入点：波场分离　出处：《大地测量与地球动力学》2014年04期 　论文类型：期刊论文

【摘要】：基于二维有限元数值方法,模拟复杂条件下隧道内的地震全波波场,分析隧道地震超前预报中反射记录的多方向和多波反射波特征,证实分离前方有效反射波和其他方向的干扰反射波,以及有效反射波的P波、S波分离在预报准确性中的重要性。基于多个数值模型,研究了F-K变换进行波场分离的有效性和影响因素。研究表明,在隧道前方反射层倾向与隧道轴线交角变化较大范围内(90°~45°),F-K变换都可以有效分离多方向和多波反射事件,提取主要来自掌子面前方的有效反射波剖面。来自隧道顶、底的缓倾界面的具有双曲时距曲线特征的干扰波和S波的高视速度会对P波的波场分离产生较大干扰;而由于S波的低速和强能量特征,其波场分离受具有双曲时距曲线特征的干扰波的视速度影响较小,且不受P波的影响。
[Abstract]:Based on the two-dimensional finite element numerical method, the seismic full wave field in the tunnel under complex conditions is simulated, and the multi-direction and multi-wave reflected wave characteristics of the reflection record in the tunnel earthquake prediction are analyzed. The importance of separating the front effective reflection wave from the interference reflection wave in other directions, as well as the P-wave S wave separation of the effective reflection wave in the prediction accuracy is confirmed. Based on several numerical models, The effectiveness of F-K transform in wave field separation and its influencing factors are studied. The results show that the F-K transform can effectively separate multi-directional and multi-wave reflection events in a wide range of angles between the reflected layer inclination in front of the tunnel and the tunnel axis, and the F-K transform can effectively separate multi-directional and multi-wave reflection events. The high apparent velocity of the hyperbolic time-distance curve and the hyperbolic time-distance curve of the slow dip interface from the top and bottom of the tunnel will greatly interfere with the separation of P waves. However, due to the low speed and strong energy characteristics of S wave, the wave field separation is less affected by the apparent velocity of the interference wave with hyperbolic time-distance curve, and is not affected by P wave.
【作者单位】：四川农业大学土木工程学院;西南交通大学土木工程学院;
【基金】：国家自然科学基金项目(40874051)
【分类号】：U452.1;P631.4

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