The acoustic study of soil liquefaction effects in-situ

Abstract

This study is aimed to describe effects of saturation with water on soil stiffness and bonds strength. Linear and nonlinear soil acoustic characteristics as dependent on saturation have been studied in-situ. At the end of experiment, the soil became unstable that allowed tracking the saturation process as a whole. The experiment was prepared as follows. Two weeks before the experiment fulfilment, the trench was dug and a hose with holes was embedded. The hose was connected to the water supply network through the water meter. During saturation, the soil acoustic responses were being continuously recorded. The soil linear stiffness has been measured by remote technique based on the analysis of the dispersion of Rayleigh wave polarization. The measurements were carried out by pairs of vertically and horizontally oriented geophones. Then, the bulk stiffness and the Poisson's ratio profiles were reconstructed. Special attention was given to the assessment of its nonlinear parameters. Effects of hysteresis nonlinearity in dependence “force versus displacement” were observed and discussed as well. The force and displacement were measured by two accelerometers mounted on the baseplate and the reaction mass of vibrational source. [The work was partially supported by RFBR, research projects No.14−02−00695, 15−05−08196, 15−45−02450, and 14−05−31249.]