THE THREE-DIMENSIONAL IMAGING TECHNOLOGY AND ITS IMPROVEMENT FOR GEOLOGICAL STRUCTURE BASED ON TRT SYSTEM

Abstract

The TRT technology is used to achieve recognition of the disaster body with the help of seismic wave reflection principle; it can locate disaster body using a confocal ellipsoid changing with time composed by seismic focus and the receiving focus. By comparing the abnormal image area formed by TRT technology with the tunnel disaster area caused by the earthquake, the TRT anomaly area is divided into four types, which is cluster abnormal area, single abnormal area, faulted abnormal area and interbedded abnormal area. Aiming at TRT technology's own problems which is that the calculation of direct wave velocity is not enough accurate and the setting of background wave velocity is unreasonable, a corresponding improvement method is proposed. On one hand, to get the actual direct wave velocity between seismic focus and the receiving focus, through calculating the minimum actual spreading track of the direct wave in the tunnel. On the other hand, to obtain 1-a confidence interval of actual direct wave velocity in the condition of Gaussian distribution, based on the distribution of direct wave velocity. To entry the upper and lower limits of the confidence interval as the background velocity into the TRT system, and gain two sets TRT's image, which gets rid of the singleness and blindness in setting the background wave velocity, and makes a certain confidence interval consideration for the improved geological hazard forecasting. The result of the present example shows that the effect of improved geological hazard forecasting is much better than the forecasting effect of setting the background wave velocity, in a certain degree, that avoids the possibility of omission in disaster prediction.