HE Xian-long, ZHAO Li-zhen, SHE Tian-li. A new method for automatic picking shear wave velocity based on energy gradient[J]. 2015, 36(3): 847-853.
DOI:
HE Xian-long, ZHAO Li-zhen, SHE Tian-li. A new method for automatic picking shear wave velocity based on energy gradient[J]. 2015, 36(3): 847-853.DOI: 10.16285/j.rsm.2015.03.031.
A new method for automatic picking shear wave velocity based on energy gradient
A new autoregression curve method based on energy gradient is proposed. It can improve the accuracy of measuring shear wave velocity with single-hole method. Firstly
the time-history curves of shear waves are transformed into a set of spatial energy gradient wave time-history curves. Secondly
short trigger average/long trigger average (STA/LTA) method is used to transform energy gradient wave time-history curves and pick the arrival times of P wave and S wave. Finally
a quadratic autoregression model is proposed to pick the accurate arrival times of P wave and S wave. The model is used to process the energy gradient curves near the arrival time. A comparing experiment is conducted to validate the theory. The shear wave velocities of one field tested with proposed method
cross-correlation function method and manual picking method are analyzed. The results indicate that in comparison with the cross-correlation function method
this method has a better inhibitory effect on noise
and not only can get accurately S shear wave velocity but also can get accurately P shear wave velocity. Meanwhile the proposed method has much higher accuracy and stability in practical test relative to the manual picking analysis. This method enriches the automatic-picking methods of shear wave velocity. On the basis of method proposed in this paper
cross-correlation function method and manual picking method
a shear wave measurement system is designed. It is easy to pick shear wave velocity automatically and produce a test report by this system.