ABSTRACT Tunnel seismic prediction is widely used in the field of tunnel seismic advance detection. The illumination of the target and the signal‐to‐noise ratio of the data are two key factors affecting the precision of data interpretation. Current seismic prospecting has shortcomings on sites: (1) The lighting shots are solely towards one side of the tunnel wall, (2) the geophones are placed far away from the tunnel face and (3) the surface waves from the tunnel wall dominate over the reflection waves, lowering the signal‐to‐noise ratio of the data at the tunnel wall. This paper proposes a tunnel symmetrical geometry to tackle the above challenges. The arrangement is to place 12 sources uniformly on each side of the tunnel wall and six geophones on the tunnel wall and face. Results of simulated data and measured data show that the proposed method enables (1) broad illumination of the target body, (2) the enhancement of illumination energy of the target body, and (3) higher data signal‐to‐noise ratio. The proposed symmetrical geometry method provides better interpretation in terms of broader coverage, higher quality and greater distance of investigation.

中文翻译：

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宽照度高信噪比隧道地震超前预测方法

摘要 隧道地震预报广泛应用于隧道地震超前检测领域。目标光照度和数据信噪比是影响数据解释精度的两个关键因素。目前的现场地震勘探存在以下不足：（1）照明弹仅针对隧道壁的一侧，（2）检波器放置在远离隧道掌子面的位置，（3）来自隧道壁的面波占主导地位。反射波，降低隧道壁数据的信噪比。本文提出了一种隧道对称几何结构来解决上述挑战。布置方式是在隧道壁两侧均匀放置12个震源，在隧道壁和工作面均匀放置6个地震检波器。模拟数据和实测数据结果表明，所提出的方法能够实现（1）目标体的广泛照明，（2）增强目标体的照明能量，以及（3）更高的数据信噪比。建议的对称几何方法在更广泛的覆盖范围、更高的质量和更大的调查距离方面提供了更好的解释。