Abstract:

In order to study the mechanical behaviour of frozen soil under the roadbed of the Qinghai-Tibet Railway and explore a new method to estimate the uniaxial compressive strength quickly and correctly, the stress-strain-electrical resistivity experiments for the clay in Beilu River are done under different temperatures during the whole process of uniaxial compression. The complete testing data for the stress -strain curve and the associated electrical resistivity -strain curve are obtained. The experimental results indicate that the uniaxial compressive strength increases with decrement of the temperature T, and they follow the linear relationship. The initial electrical resistivity rises while the temperature decreases; however, initial electrical resistivity increases sharply with increment of T when ℃. The relationship between uniaxial compressive strength and the initial electrical resistivity can be described as linear Semi-logarithmic equation , whose correlation coefficient is very high, so can be quickly and correctly estimated by which can be measured more conveniently. The stress-strain curve can be separated into compression stage, elastic stage, plastic flow stage, break-up stage corresponding to decreasing fast stage, decreasing to minimum stage, steady increasing stage, unsteady increasing stage in resistivity-strain curve. This associated relationship indicates that the strength and displacement problem can be effectively solved by the electrical resistivity method.

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