关键词: 冻土, 单轴压缩, 切线模量, 应力-应变-电阻率, 机敏性, 温度, 青藏铁路

Abstract:

Using the frozen soil uniaxial compressive apparatus combined with electrical resistivity observation for whole process, a series of uniaxial compressive tests under different environmental temperatures are performed for the clay in Beilu River with an initial water content of 17.8 % and dry density of 1.71 g/cm3 under a loading strain rate of 1 mm/min, in which the complete testing data for the stress -strain curve and the associated electrical resistivity-strain curve are obtained. The experimental results indicate that , , are increased with decrement of the temperature T and they are changed synchronically. The frozen soil performs highly pressure-sensitivity, with the increasing of stress, the procedure of electrical resistivity includes three stages: decreasing stage, balance stage and sharply increasing stage. There is the linear relationship between the largest tangent modulus and temperature. , , show sensitivity to temperature, the value of , , is minimum when the temperature is -15℃. The ductibility of frozen soil is enhanced and its brittleness is reduced; at the same time , , are increased with the decreasing of the temperature, when ℃.The frozen soil has opposite characters when ℃.

Key words: frozen soil, uniaxial compressive strength, tangent modulus, stress-strain- electrical resistivity, alert performance, temperature, Qinghai-Tibet Railway