Influence of freeze-thaw cycles on resilient modulus of different plasticity index subgrade soil

Three different plasticity index subgrade soil are selected from seasonal frozen soil region. Static triaxial test is executed on the samples exposed to 0 to 7 times closed-system freeze-thaw cycles under different confining pressures. Resilient modulus is obtained from the line segment of deviator stress-strain curve. The results show that the resilient modulus of the same kind of soil increases with confining pressure; under the same freeze-thaw cycles, Resilient modulus with the same confining pressure decreases with the number of freeze-thaw cycles; Under the same confining pressure and the same freeze-thaw cycles, resilient modulus increases with the plasticity index. The exponential function is adopted for multiple nonlinear fitting. The relationship between resilient modulus and confining pressure, plasticity index, freeze-thaw cycles is obtained and shows a good correlation.