Abstract:
The general pulse reflection method, time reversal (TR), and reversed time migration (RTM) techniques all can't distinguish the target (flaw) close to the interface due the superposition of the target reflection waves and the interface reflection wave. Although the modified TR (i.e. TR with exchanging elements) can distinguish target (flaw) from the interface, yet can't implement the target location. In the paper, a mixed method of TR and RTM is proposed. The analyses and simulation results show that not only the targets in layered media can be detected but also be located with the method. And for multiple targets, their location distributions can be obtained. It is of potential value foracoustic detection and location of flaws in layered media and targets under the bottom of shallow sea.