Variation characteristics of resistivity of saturated sand samples during liquefaction

In order to investigate the changes of pore structure of saturated sand during its liquefaction, an equipment for testing the electrical resistance of samples based on the dynamic triaxial equipments is independently developed based on the general understanding of the quantitative relationship between the pore structure and the electrical resistivity of sand. The electrical resistivities of samples with different relative densities under varied cyclic amplitudes of loading are tested, adopting the method for calculating the electrical resistivity of a sample with variable heights and invariable volume established. The experimental results show that the fluctuation of the electrical resistivity is not obvious at the initial stage of cyclic loading, and gradually more violent fluctuation when the pore pressure of the sample is relatively high and the dynamic strain fluctuation is relatively large. The amount of resistivity variation at the end of each cycles, which is affected by the relative density of the sand sample and the amplitude of dynamic load, decreases with the increase of vibration number and can be divided into three distinct stages: steady decline, rapid decline and slow decline. It is also inversely proportional to the pore pressure ratio, and continues to decrease after the initial liquefaction. Based on these test results, the specific regularities of pore structure changes in saturated sands during liquefaction are discussed. This study facilitates the understanding and evaluation of the liquefaction behavior of saturated sands from the perspective of pore structure changes.