Exploring the Influence of Seismic Source and Improvement Methods on Tunnel Seismic Prediction

Tunnel seismic advanced prediction method is essential for detecting abnormal bodies ahead of the tunnel face and minimizing risks during tunnel construction. Selecting the seismic source plays a crucial role in influencing the precision and effectiveness of data acquisition. At present, tunnel seismic data is usually collected using explosive and sledgehammer sources. Nevertheless, the various sources are located in different positions within the tunnel excavation zone, resulting in distinct characteristics observed on the surface and reflected waves in the acquired tunnel seismic data. The explosive source has minimal surface wave interference, but it is expensive. However, the sledgehammer source is economical yet plagued by inadequate energy and substantial surface wave disruption. Regrettably, there is a lack of research on seismic sources in tunnels, which impairs the precise interpretation of forecasting conclusions from these sources. This paper seeks to investigate how various sources impact tunnel seismic prediction and suggests a new method that integrates data acquisition and processing from these sources. The explosive source is used once, while the sledgehammer source is used 24 times. Cross-correlation calculations are conducted to enhance the resolution of sledgehammer source data, reducing surface wave interference, based on seismic data obtained from the explosive source. Extensive numerical simulations and tunnel experiments support the validity of this method, highlighting its potential to lower data acquisition expenses and enhance tunnel seismic prediction accuracy.