Experimental Study of Warm Permafrost Mechanical Property Under Cyclic Load

In order to study the dynamic response of the warm permafrost subgrade under traffic loads, the low temperature dynamic triaxial test was conducted on remolded soil which extracted from Yakeshi highway in Inner Mongolia Autonomous Region and gained the hysteretic loop curves, while the deviatoric stress changes from 0 to 50 kPa. The cyclic loading frequency is 6 Hz and the test temperature is  −  1.5 ℃. The result shows that each deviatoric stress–strain hysteresis loop can be divided into two parts, and data points can be described by sine function separately for each part. The phase angle of sine function is changing with the number of loading cycles and the sample always keeps stable. The warm permafrost hysteresis loop area linearly reduces and the dynamic modulus exhibits a pattern of initial increase, followed by a decrease, and then a subsequent increase.