Detection Of Shallow Subsurface Contamination Based On Ground Conductivity Meter

Ground conductivity meter,as a non-invasive and efficient geophysical exploration technology,has been widely used and researched in environmental pollution investigation in recent years,but it faces challenges such as unstable measurement data and low signal quality.This paper conducts research on highresolution pollution detection methods using ground conductivity meter in shallow subsurface,and proposes a data optimization method based on high-density electrical resistivity,achieving high-resolution pollution detection.The research results provide theoretical support for the application of ground conductivity meter in shallow subsurface pollution detection,and provide technical support for fine soil pollution investigation.The main work and achievements of this paper are as follows:(1)Conducting research on the high-resolution detection method of ground conductivity meter for shallow subsurface pollution based on high-density electrical resistivity.Select appropriate electrode spacing and measurement array according to the expected measurement depth,and establish a corresponding ground model.Simulate the model using high-density electrical resistivity,obtain accurate apparent conductivity data,and then calibrate the measurement data of the ground conductivity meter through the established fitting equation to achieve high-resolution detection.(2)Conducting numerical simulation research on the different distribution characteristics,conductivity characteristics,and instrument height above ground level of pollutants,and reveal the effects of different characteristic pollutants and instrument height on the high-resolution detection method.The applicability of the method is analyzed for the distribution characteristics of block,layer,upright,and fault,and the results show that after optimization,the inversion result can more accurately characterize the lower boundary of the anomaly body,and the optimization result is closer to the true model when the anomaly body is shallower,causing a relative increase in the resistivity value of the surrounding rocks of the anomaly body,making the position of the anomaly body more prominent,and the optimization effect of the layer-like distributed anomaly body is the least obvious.Through the study of the applicability of low-resistance anomaly bodies and highresistance anomaly bodies,it shows that there are significant optimization effects for anomaly bodies with different electrical characteristics,and the position distribution of the anomaly body is closer to the true distribution of the model.The statistical information of the inversion results shows that the optimization effect of the method on low-resistance anomaly bodies is higher than that of high-resistance anomaly bodies.The instrument height above the ground level is also an important factor affecting the data quality and optimization effect.The results show that the lower the instrument height above the ground level,the more effective information can be obtained,and the optimization effect is better,which is consistent with the analysis results of instrument depth sensitivity.(3)Based on field exploration examples,the effectiveness and applicability of the high-resolution detection method in engineering examples were studied.Select the high-density electrical method survey line results with high correlation as the calibration basis,fit the electromagnetic induction method results at the same position,and apply the obtained fitting equation to optimize the detection results of the entire site.The pollution site was successfully divided according to the degree of pollution,and the pollution range and soil volume were calculated,providing guiding opinions for subsequent detailed pollution investigation and pollution control.