Electrical resistivity change of saturated sand during reliquefaction under hammering loading

Experimental Study on the Electrical Resistivity Characteristics of Uniformly Graded Calcareous Sand

“…Table 4 shows that all the fitting correlation coefficients were greater than 0.96, and a stronger correlation could be obtained by using the power function relationship. For sandy soil, when the porosity n was 0.12-0.50, the coefficient m was between 1.3 and 2.8 [16,26,27]. Compared with sandy soil, the coefficient m of calcareous sand was larger, indicating that the resistivity of the calcareous sand used in this study decreased rapidly with increasing porosity, which may have been related to the pore structure of the calcareous sand itself.…”

“…(5) A sample was inserted into the sample box, the electrodes were connected at both ends of the sample to the digital bridge measurement port, and the resistance value was read. The data reading was completed within seconds, ignoring the impact of the sample's previous electrification on the test results [16]. Simultaneously, the indoor temperature was controlled within the range of 20 ± 2 • C to reduce the impact of the test temperature on the results [17,18].…”

“…When the current passes through the contact point between the calcareous sand and the electrode, a contact resistance is generated at the contact point, mainly caused by the contraction resistance between the electrode and the medium and the oxide film on the surface of the metal electrode. Studies [16,19,20] have shown that, in the process of using the two-electrode method to test the resistivity of soil, the contact resistance between the sample and the electrode affects the results. To eliminate the influence of contact resistance, in this study, the contact resistance between the calcareous sand sample and the electrode was obtained through experiments and then corrected for the subsequent experimental results.…”

“…This was because as the concentration of pore water salt increased, the number of conductive ions gradually met the conductive needs of the pore water Using the above six solutions, saturated calcareous sand samples with relative density D r = 0.6 were prepared, consisting of three size fractions: 1-1.5 mm, 1.5-2 mm, and 2-2.5 mm. To prevent differences in ion adsorption by particles [16], calcareous sand was not reused. The electrical resistivity results of these saturated calcareous sands obtained through testing are shown in Figure 8.…”