Study On Monitoring Soil Water Through Electrical Resistivity Tomography

Electrical resistivity tomography is a kind of more extensive exploration method which is based on the differences of the resistivity of rock,ore.It has the characteristics of High resolution and low economic cost,high efficiency,rich information,easy to explain.Electrical resistivity tomography has showed great development prospects,but It is applied more in the field of geological prospecting,It needs to study in the applicability of more complex,more fine soil characteristics and processes.There are many ways of Monitoring soil moisture content,and Electrical resistivity tomography is a way of no injury detection,electrical characteristics of the soil can be comprehensive detection especially in 2d or even 3d profile detection,it is simple and effective at the same time.It has good practical significance to get change and change process in soil hydrological processes through research the relationship between the soil resistivity and water content.Many factors affect soil resistivity changes,including the type of soil,porosity,particle size,etc.,but the influence factors of temperature and moisture content is very important.ERT is destructive,it can generate soil resistivity change of two-dimensional or three-dimensional space and time,it is apparent resistivity through the resistivity imaging method,we need to run data inversion in order to obtain the true resistivity distribution.This project intends to carry out the resistivity imaging method in the researches of the hydrological process observation,we hope that the results of the study can improve the high density resistivity imaging method,realize technology exchange between exploration learning,soil science and hydrology.This paper studies the measurement and inversion technique by electrical resistivity tomography,and study the relationship between resistivity and water content through numerical simulation,and study the relationship of moisture content and stored soil water by TDR and ERT measured.The study find that the three layers of the residential area in soil layers,relationship of soil resistivity and volumetric water content has a better match the experience Archie formula in each layer,we also find that the fit of the clay layer is the highest,30 cm above the fit of the magnetism is better also,the fit of the bottom is poorer.For relationship of moisture content and stored soil water by TDR and ERT measured,we find that the performance of the middle and upper are higher,the performance of the lower is poorer.This experiment is to use shallow soil layered approach to study on the relationship between the soil resistivity and water content,resistivity of electrical resistivity tomography monitoring instrument gets the true resistivity through inversion,Measurement data uses inversion,interpolation,fitting,temperature correction way to fit relationship of the resistivity and water content,we acquire relationship of the soil resistivity and water content by empirical formula of Archie.Time span is large,there are lots of environment and other various interference factors,monitoring process also may encounter various difficulties and problems.Research should strengthen the accuracy of measurement technology,reduce the measuring error,try to eliminate the interference of various adverse effects in future,we can better predict the relationship of the water content and soil resistivity.