Strength properties of ice-rich frozen silty sands under uniaxial compression for a wide range of strain rates and moisture contents

Abstract

With the increase in engineering construction in ice-rich permafrost regions, the strength characteristics of ice-rich frozen soils have attracted the attention of researchers and engineers. However, few laboratory data address the uniaxial compressive strength of frozen soils for a wide range of strain rates and moisture contents. In the present study, a series of uniaxial compressive tests were conducted on ice-rich frozen silty sands using temperature conditions of −0.5, −1.0, −2.0, and −5.0°C, moisture contents of 16.7–480.0%, and strain rates of 1.07×10−5 to 1.13×10−2s−1. The results show that brittle failure occurs easily in the ice-rich frozen silty sands, except for those with a moisture content of approximately 31.0%. When the moisture content is low, the strength increases nonlinearly with increasing strain rate. However, when the moisture content is high, a peak strength appears on the strength–strain rate curve. For strain rates less than 5.33×10−4s−1, as the moisture content increases, the strength first decreases from a maximum value at optimum dry density to a minimum value that is less than the ice strength. The strength then increases to the ice strength. For strain rates greater than 2.00×10−3s−1, as the moisture content increases, the strength first decreases to a minimum value, then increases to a maximum value, and finally decreases toward that the ice strength; the minimum strengths are not always less than the ice strength, and the maximum strengths are not also always greater than the strengths at the optimum dry densities.