Dynamic Properties of Frozen Silt Under Cyclic Loading

Cyclic triaxial tests were conducted to evaluate the dynamic properties of laboratory prepared samples of frozen silt under simulated earthquake loading conditions. Dynamic Young's modulus and damping ratio were evaluated for Hanover and Alaska silt at two water contents over axial strain amplitudes from approx 2x10^-³% to 8x10^-²%, temperatures from 30.2°F to 14°F (-1°C to -10°C), frequencies from 0.05 cps to 10.0 cps, and confining pressures from 0 psi to 200 psi (0kN/m² to 1400kN/m²). Values of dynamic Young's modulus obtained over the range of test parameters were from 1x10⁵ psi to 35x10⁵ psi (7x10⁵ kN/m² to 245x10⁵ kN/m²) for Hanover silt and 1x10⁵ psi to 22x10⁵ psi (7x10⁵ kN/m² to 154x10⁵ kN/m²) for Alaska silt; values of damping ratio ranges from.02 to.36 for Hanover silt and from.02 to.32 for Alaska silt. The test results indicate that dynamic Young's modulus of frozen silt decreases with increasing axial strain amplitude and temperature, increases with increasing frequency, and is unaffected by confining pressure. The damping ratio increases with increasing axial strain amplitude and temperature and decreases with increasing frequency, water content, and confining pressure.