Dynamic properties of frozen soils. Part 2. Triaxial compression tests

In the first part of the series of articles, which are offered to the readers of the “Geoinfo” journal, the results of testing frozen soils in a resonant column were presented in detail. As an analysis of published data shows, studies of the dynamic properties of frozen soils is often carried out using the triaxial compression method. Its advantage, compared to testing in a resonant column, is the possibility of assessing the elastic-viscoplastic deformations of frozen soils. Testing by this method using low-frequency high-amplitude vibrations make it possible to evaluate the mechanical behavior of frozen soils (for example, under seismic influence). This article provides a literature review of the results of triaxial compression tests of frozen soils with an emphasis on temperature variations. The results of generalization of the dynamic properties of frozen soils show that at low negative temperatures ( –10 °C or lower) the deformation modulus is usually more than 4000 MPa, at temperatures from minus 3 °C to minus 5 °C it varies on average from 600 to 3000 MPa, at temperatures higher than minus 3 °C it decreases to 715–400 MPa, depending on the composition, properties of the tested soil and on the test conditions. The damping ratios of frozen soils (D) vary in a wide range (from 0.01 to 0.2 and higher), depending on the composition, humidity, temperature of the tested soil and on the test conditions). Most publications note increasing damping ratio values with increasing temperature of the tested frozen soil. This article also presents the results of measuring the pore pressure of soil, which have a temperature of minus 0.2 °C, during its dynamic loading.