Studies On Landmine Detection Experimental System Based On Acoustic To Seismic Coupling

The war remnant landmines have been a severe threat or even a cause of poverty to the people's lives and life of correlated countries and regions. It's always an important object of humanitarian landmine detection activities to clear buried landmines effectively and fleetly. The widespread used metal detector can not detect nonmetal landmines effectively and can't meet the humanitarian landmine detection requirement. It's urgent to find new landmine detection technologies. Since the 1980s, foreign scientists began to focus on the acoustic to seismic coupling landmine detection technology which showed a nice landmine detection prospect in the lab, especially for the nonmetal landmine, but little domestic-related news has been reported.The objective of this paper is to do some preliminary studies about the technology and develop a landmine detection experimental system. After reading relative publications and integrating the experiment phenomenon, the principle of acoustic to seismic coupling and the propagation characteristic of seismic wave are summarized. The landmine and its upper soil are equated to a lumped quality spring damping model and the resonance mechanism between seismic wave and landmine-soil system are also analyzed. Besides, considering laboratory situation, an acoustic to seismic coupling landmine detection experimental system based on the geophone array has been developed. The system employs high power loudspeaker to emit single and changeable sine-wave tone to couple into the ground and the ground vibration signal can be acquired by geophone array. The signal will be processed by LabView and Matlab software on upper computer and its frequency-spectrum amplitude curve is obtained.Based on experiments, ground vibration frequency-spectrum amplitude curves are obtained respectively both when the depths of buried landmines are 9cm, 11cm and 13cm and when no landmines are buried. The curves'humps are explained by introducing the constructive interference principle, the propagation characteristic of coupled seismic wave and the resonance effect between the seismic wave and the landmine. At last, a comparison between the ground vibration data with and without buried landmine is made and it can be found that the buried landmines enhance the ground vibration at a frequency band between 400Hz to 700Hz, which can be considered as the optimal landmine detection motivation frequency band on the lab condition.