Keywords:Frozen soil, uniaxial compressive strength, temperature, resistivity, tangent modulus
Resistivity and conductive alertness is an inherent attribute of frozen soil, and a new method to estimate the frozen soil uniaxial compressive strength quickly is developed based on the resistivity and conductive alertness. The mechanical behavior of the Qinghai-Tibet Railway subgrade filling under load is investigated, indoor frozen soil uniaxial compression tests are conducted with the silt clay of Qinghai-Tibet Railway subgrade filling at different temperatures, resistivity is monitored during the whole test process. In this way, the stress-strain-resistivity curve is obtained, and the influence of temperature on the resistivity and conductive alertness is discussed. Results show that the frozen soil shows the similar properties as a varistor under compressive condition; with the increasing of the compressive stress, the resistivity can be divided into three variation intervals: a reduction zone, a balance zone, and a sharp increasing zone. When the dry density and water content is 1.71g/cm3 and 17.8% respectively, the original resistivity, maximum resistivity, and the largest tangent modulus of the frozen soil increase simultaneously with the temperature decreasing. The relationship between uniaxial compressive strength(qu) and original resistivity of the frozen soil satisfies with the equation, a new method of frozen soil strength quickly estimation is proposed and owned wide prospects of engineering application in the future.