RESEARCH ON THE SWCC OF UNSATURATED NATURAL RESIDUAL SOIL

By means of the vibration test system as well as the ultrasonic testing device and dynamic signal analysis system, the experiment on rock mass with weak intercalation fatigue damage are performed under cyclic loading. The acoustic parameters during defect rock fatigue damage are real-time measured and analyzed in detail. Results show that the ultrasonic wave velocity varies particularly sensitive to the fatigue cycle and reduces with an inversed S-shaped line. The waveform changes from an approximate semicircle to malformation, and the waveform correlation coefficient is descending as a whole with the cyclic times increasing. The ultrasonic wave amplitude has an intense fluctuation in the middle of the fatigue damage. And the rules of frequency-domain characteristics is not obvious, only when sample is nearly damaged, the maximum value of frequency domain and frequency decline sharply, which lead to a hard effective analysis and recognition of the frequency-domain characteristics. Finally, a damage variable is defined based on the transverse ultrasonic wave velocity and the Logistic inverse function equation and the nonlinear quartic polynomial are used to describe the growth law of rock mass with weak intercalation fatigue damage. The results may offer theoretical references for slope fatigue stability evaluation and reinforcement engineering under different kinds of vibration environment.