The Study Of Digital Processing Technology In Transient Rayleigh Wave Exploration

Rayleigh wave exploration is a new seismic exploration method forlow layer in these years. The method is being applied widely to manyaspects, such as engineering prospecting, rock and soil engineering,evaluating foundation. The main idea is to make use of frequencydispersion curve of Rayleigh wave to reveal geology structure of lowlayer. Rayleigh wave exploration is divided into steady state way andtransient state way according to the different of exploding mode. Atpresent, people adopt transient method mostly.In data processing of Rayleigh wave, the normal data processingmethods are the phase analysis technique and the two-dimension F-Kdomain analysis technique both based on Fourier transform. BecauseFourier transform is based upon pure mathematics and applicationmathematics, which is described for the effective means in study ofsteady signal, also it can be used to describe symptom of signalcomplete in time domain or in frequency domain, can not be used todescribe the nature of the signal both in time-frequency domain, while fornon steady signal this is the most basic and most crucial nature.Therefore, for conventional data processing technique thedisadvantages of different conventional program is as follows:The phase difference analysis method is to calculate the timedifference of Rayleigh wave traveling from one detection point toadjacent detection point. In calculating appearance speed, the phasedifference must be in main value interval, when it is larger than 2πforphase difference, using this method to calculate Rayleigh waveappearance speed is not accurate. This have restricted the distancebetween detection point, that is to say trace space should not be largerthan one or more periods in difference of effective wavelength using incalculate phase difference process. On the other hand, in calculatingprocess the phase difference locate in denominator, therefore, thesmaller phase error of the phase difference can arouse Rayleigh waveappearance speed greater change.The F-K domain analysis technique is more effective than the phasedifference analysis method for it using the data of many seismic traces,and more accurate in calculating of Rayleigh wave appearance speed.However this kind of method have adopted identical frequency steplength in drawing frequency dispersion curve process, adopted halfwavelength theory ( VR = f ?λR = f ?2H , H is exploration depth). In...