Abstract: The use of numerical simulation methods directly in surface exploration will result in numerous issues, including slow calculation speed, poor boundary absorption effect, and significant dispersion. As a result, a forward simulation method for detecting tunnel in advance is proposed. The firstorder velocitystress elastic wave equation is calculated using a highorder staggeredgrid finite difference method to obtain wavefield information at any time; the appropriate mesh accuracy and difference order are chosen to satisfy the stability conditions, and the perfectly matched layer of a new attenuation function is used to absorb boundary to deal with the reflection problem caused by artificial boundary. Further, the staggered grid and flux corrected transport method is adopted to restrain the dispersion. Finally, in heterogeneous media, an inclined layered tunnel model and a cavity tunnel model are established to simulate the processes and obtain clear wavefields and data, proving the feasibility of the forward modeling method.

Key words: tunnel advance detection, seismic wavefield simulation, numerical calculation, perfectly matched layer absorption boundary