Effect of moisture content on mechanical and damage behavior of frozen loess under triaxial condition along with different confining pressures

Abstract

Combining to the triaxial compression or loading-unloading cyclic tests of frozen loess with moisture content of 12.31% and foregoing testing results with moisture content of 16.68% and 23.70% to further investigate the effect of moisture content on strength, stiffness and damage behaviors of frozen loess. The mechanical and damage parameters, i.e. triaxial shear strength, secant modulus E50, unloading modulus, dissipated energy (elastoplastic coupling degree) and damage degree, are investigated in detail. The effect of moisture content on mechanical properties under different confining pressures is analyzed firstly. The moisture content has a significant influence on the stress–strain-volume change curve,which dominates the evolution trend of mechanical properties. Triaxial loading/unloading cyclic tests under different confining pressures are capable of determining the damage parameters as well as their degradation laws during triaxial tests. The test results indicate that the moisture content of frozen soils is an important factor for damage parameters during the deformation process. The influences of confining pressure on both the mechanical and damage behaviors of frozen loess are sensitive to the moisture content of frozen loess, which indicates that the effects of moisture content and confining pressure are coupled. The difference of consolidation degrees and pressure melting caused by the confining pressure for the frozen loess with different moisture contents is response for the coupled effect of the moisture content and confining pressure.