DYNAMIC TESTS OF FROZEN SAND SOILS

Abstract

The study of the laws of contact interaction of hard and deformable impactors with frozen soils is of great scientific and applied value. In solving such problems, numerical methods are widely used. For numerically modeling the behavior of frozen soil under dynamic loading, it is necessary to use models of soil media that adequately describe their behavior at various negative temperatures, humidities and strain rates. To identify the parameters of these models, experimental studies are required for determining dynamic properties of soils at low temperatures. The paper presents the results of experimental studies of dynamic deformation of samples of frozen sand with humidities of 10% and 18%. Compression experiments were conducted using a stand implementing the Kolsky method. Deformation curves of frozen sand at a temperature of -18 °С were obtained under uniaxial stress conditions at various strain rates in the range of 400-2500 s-1. Diagrams of strength of frozen sand under uniaxial compression as a function of strain rate are constructed. The diagrams are linear for samples of different humidity in the studied range of strain rates. Maximum stresses in frozen water-saturated sand are higher than those in frozen sand of 10% humidity. With increasing strain rate, compressive strength of water-saturated sand grows faster than that of sand with a moisture content of 10%: at a strain rate of about 500 s-1, the stresses in frozen water-saturated sand, at which the samples fail, are 1.5 times higher than those in the frozen sand with a moisture content of 10%, and at a strain rate of 2500 s-1 they are 3 times as high.