High-Resolution Imaging And Interpretation Of High-Density Resistivity Method

High-density resistivity method is a commonly used geophysical exploration method.Compared with the traditional resistivity methods,the high-density resistivity method enables automatic switching of electrode device type,electrode spacing and measuring point during measurement,thus improving detection accuracy and efficiency.In practical applications,the detection data of the high-density resistivity method is usually inverted by the smooth-constrained least-square method.However,according to the inversion results,although the resistance distribution in the detection area can be obtained,it is difficult to accurately determine the specific position of the boundary between the different resistivity regions,which in turn affects the accuracy of the detection data interpretation results.To solve the above problem,a high-resolution imaging and interpretation method based on the analysis of reflection coefficients is proposed in this paper.This method can achieve the amplification of the data feature at the boundary of the abnormal area by carrying out effective secondary processing and analysis of the inversion section data,so as to identify the specific position of the boundary of the abnormal area in the inversion section,improve the accuracy of the data interpretation results,and provide more reliable theoretical guidance for the actual project.Therefore,the study of the high-resolution imaging and interpretation methods of high-density resistivity method is of practical significance.At present,there is little research on the high-resolution imaging and interpretation by the secondary processing of the inversion data of the high-density resistivity method.(1)This paper is mainly analyzed by numerical simulation.First,the inverse results obtained by the smooth-constrained least-square method are interpolated and meshed using Kriging interpolation method,and then the complete boundary of the abnormal area is determined by analyzing the reflection coefficients of each set of horizontal and longitudinal grid data through the abnormal response area in the inverse section after smooth processing,and the high-resolution image of the boundary position is drawn according to the analysis results.At the same time,the boundary coefficient method is used to analyze the error of each boundary identification result,and the high-resolution imaging and interpretation of high-density resistivity method are realized.(2)By comparing the effect of the method in various models,the factors affecting the accuracy of the method are analyzed.At the same time,by using the comprehensive comparative analysis of multiple sets of horizontal and vertical grid data and their reflection coefficients,the effect of different factors on the accuracy of boundary identification results is reduced or eliminated,so that the results of the analysis are more realistic.(3)The engineering application of the high-resolution imaging and interpretation method of high-density resistivity method was carried out by using a mileage segment of Dalian Metro Line 5 project.Comparing the inversion section image of the detection data with the high-resolution image of the boundary position of the abnormal area based on the analysis results of the method proposed in this paper,it can be known that the specific location of the boundary of the abnormal area can be effectively determined by the method proposed in this paper.At the same time,by comparing the site excavation results with the analysis results,it can be known that the recognition results of this method are basically consistent with the actual situation.Therefore,the method proposed in this paper can accurately identify the specific location of the boundary of the abnormal area in the inversion section of the high-density resistivity detection data,so as to achieve the high-resolution imaging and interpretation of high-density resistivity method.