The Ac Impedance Characteristics of Soil with Different Water Content

Abstract

As an important and mature technology of researching material properties, ac impedance spectroscopy has successfully applied in many discipline except for soil research. Based on the experiments using TH2828A wide frequency LCR meter (from 50 to 106 Hz), the ac impedance characteristics with different water content of soil had been discussed. The results fully illustrate that the ac impedance is one of the basic property of soil,and the value of ac impedance parameter can be reflected the water content quantitatively. when using the fixed frequency to measure ac impedance of soil, it is most suitable as the frequency equals 104 Hz.The measure method of ac impedance have no effect to physical properties and internal structure of soil.

Moisture–Conductivity Calibration for Electrical Imaging of Horticultural Substrate

“…Meanwhile, there are similar characteristics for the other sets of measured conductivity (or resistivity) spectra. Moreover, the above results (or characteristics) are basically consistent with those in the previous works [17,18].…”

“…Meanwhile, there are similar characteristics for the other sets of measured conductivity (or resistivity) spectra. Moreover, the above results (or characteristics) are basically consistent with those in the previous works [17,18]. Overall, for the substrate at relatively constant ρ d , the increase in θ mainly results in significant and regular increases in |σ meas | and σ meas .…”

“…In these studies, the effect of the water saturation, which can be related to the VWC through the porosity, on the complex conductivity were investigated, and it was shown that the magnitude of complex conductivity, the in-phase conductivity, and even the quadrature conductivity follow power-law relations with the saturation [11][12][13][14][15]. Additionally, in some other works focusing on soil moisture measurements, the related electrical measurements were performed in wider frequency ranges of up to several MHz, and despite the presence of the effects of electrode polarization, the related results show good regular relations at different frequencies between the measured resistivity (or impedance, conductivity) and the water content [16][17][18]. In addition to the VWC, the dry density related to the porosity also has an effect on the soil conductivity; there are also some studies focusing on the effects of factors such as moisture and density on DC conductivity (or resistivity) of soils, where static compaction was used to control the density of the related samples [19,20].…”

“…For materials such as soils and substrates, the water phase is usually the main conductive path, and thus, the conductivity is generally dependent on the water content, salinity, connectivity in the pore network, and conduction on the particle surface [20]. As the water content increases, the pore water connectivity is improved, and thus, the conductivity increases [17,19,20]. The results in this study indicate that the magnitude of complex conductivity and the in-phase conductivity follow good power-law relations with the VWC, and these results are consistent with those in the previous works [11][12][13][14][15].…”

Experimental Study of Effects of Different Factors on Electric Resistivity of Cemented Soil

“…In fact, in recent years, domestic and foreign scholars have used electrical resistivity method on research of soil and cement soil, Guohua Liu [3], analyzed the primary and secondary factors affecting soil resistivity change and the establishment of the resistivity model clay, Xiaoqiang Dong et al [4] quantitatively studied the effect of sulfuric acid pollution on the electrical resistivity of soil -cement and established formula of predicting arbitrary sulfuric acid concentration and curing age cement soil resistivity. The above shows that the resistivity is affected by many factors in the practical application, such as age, pollutants, the frequency of test [5], water content, porosity, in order to distinguish the severity of common factors between primary and secondary order in this paper, using the orthogonal experimental method to study the effects of cement soil resistivity changes among the curing period, sodium sulfate content and alternating current frequency , and qualitatively analysed the influence of these three factors on the variation of cement stabilized soil resistivity. First mixing sodium with water into 2.5, 5, 10, 20g/kg , then made the original soil crushed, dried, sieved, weighed an appropriate quality of dry soil and put it into the pre-made sodium solution , stir, then sealed, standing 7d to make contaminated soils .Put the polluted soil, cement, water in the ratio of 1:0.15:0.345 into small mixer and stirred, then load it into the side length of 70.7 mm specification test mode, vibrated 5min, placed 24 h released and made a number ,sent to the standard curing box to 7, 14, 28, 60, 90, 180, 360d.…”