Experimental Study On Seismic Characteristics Of Explosives

The formation mechanism of the seismic wave by the explosive source is verycomplicated, which include many physical processes. The wave field can be divided intotwo areas, the near field and the far field, based on the characteristic of the seismic wavefield. In the near field, the variation of the energy and frequency spectrum is large. After itpropagates beyond a certain distance, the feature of the wave becomes stable after thefiltering by the earth, this area can be considered as the far field. The stimulated conditionof explosive seismic source will influence directly the property of the near field seismicwave, and then affect the wave in the far field. The quality of the seismic wave in far fieldis the key factor which will influence the quality of the seismic exploration. In this thesis, itis focused on the experimental study and theory analysis on the relationship between thestimulating conditions and the energy and frequency spectrum of the generated seismicwave. From the research work, some results has been got.1） Through the comparison studies on the features of the near-field seismic wavegenerated by explosive source under the different coupling media, such as air, water,sand and soil, it can be found that the water is the best coupling media for generatingthe best seismic wave, in which the energy and main frequency can be improved by5-10%.2） Adjusting the coupling factor is also a good way to change the quality of the seismicwave. When the coupling factor is around1.33the quality of seismic wave is betterunder the condition that the air is the coupling media.3） Adopting the electric fuse system, the precise control of the delay time for thedistributed explosive sources is realized. The delay distributed explosive sources canimprove the quality of the seismic wave and decrease the ground surface shocksimultaneously. The main frequency can be increased by10-20%, and the ground shockcan be decreased by50%.4） Changing the weight and the ratio of length to diameter of the explosive source canalso affect the property of the seismic field. The large ratio of length to diameter andsmall weight explosive source can generate higher frequency seismic wave.The research work in this thesis deepened the understanding about the influence on theproperty of the energy and frequency spectrum of the seismic wave by the stimulatecondition, explored the way for controlling the quality of seismic wave. The work will be the foundation for the further studies on the theory of high precision exploration and designof seismic wave stimulation.