摘要
研究目的:针对现阶段隧道地震反射波法超前地质预报多以二维预报为主、准确率不高的问题,提出一种有效的三维地震反射波超前地质预报观测方式,在此基础上进行数据处理与成像的成套技术研究,通过数值模拟和物理实验对其进行可行性与可靠性验证,使其能有效地应用于隧道超前地质预报生产项目中。研究结论:(1)从弹性波基本理论出发,采用锤击震源,提出了基于横波的三维地震波超前地质预报观测系统,其相较于传统采用纵波预报的方法,分辨率更高,对水体更敏感;(2)实现了基于Kirchhoff积分的偏移成像方法,其利用能量叠加准则进行三维速度扫描,并采用快速行进法进行走时计算,不受观测系统的限制,计算效率高,不需要很精确的速度模型也能得到较精确的偏移成像结果;(3)实现了隧道三维地震波场有限差分数值模拟,并且建立不同倾角岩性分界面、不同厚度断层及不同直径溶洞等典型不良地质模型,分析并总结其三维成像特征;(4)通过物理模型以及应用案例验证,本文所述方法具有可行性与可靠性,可在隧道超前地质预报中推广应用。
Research purposes: Because that most of the advanced geological prediction of tunnel seismic reflection method is based on 2D prediction and the accuracy is not high, an effective observation method of advanced geological prediction of three-dimensional seismic reflection is proposed. On this basis, a complete set of technology research on data processing and imaging is carried out, and its feasibility and reliability are verified through numerical simulation and physical experiments, which is effectively applied to the production of advanced geological prediction of railway tunnel.Research conclusions:(1) Based on the basic theory of elastic wave, a three-dimensional seismic wave advance geological prediction observation system based on shear wave is proposed. Compared with the traditional P-wave prediction method, it has higher resolution and is more sensitive to water body.(2) The migration imaging method based on Kirchhoff integral is realized, which uses the energy superposition criterion for three-dimensional velocity scanning, and uses the fast marching method for travel time calculation, which is not limited by the observation system, has high calculation efficiency, and do not need a very accurate velocity model.(3) The finite difference numerical simulation of three-dimensional seismic wave field of tunnel is realized, and the typical adverse geological models such as lithologic interface with different dip angles, faults with different thickness and karst caves with different diameters are established, and their three-dimensional imaging characteristics are analyzed and summarized.(4) Through the physical model and application experiment, the method presented in this paper is feasible and reliable, and can be popularized and applied in tunnel advanced geological prediction.
作者
蔡盛
CAI Sheng(China Railway Siyuan Survey and Design Group Co.Ltd,Wuhan,Hubei 430063,China)
出处
《铁道工程学报》
EI
北大核心
2022年第10期30-36,共7页
Journal of Railway Engineering Society
基金
中铁第四勘察设计院集团有限公司科研项目(2019K026)
湖北省重点研发计划项目(2021BAA050)。
