(1. State Key Laboratory of Frozen Soil Engineering，Cold and Arid Regions Environmental and Engineering Research
Institute，Chinese Academy of Sciences，Lanzhou，Gansu 730000，China；2. School of Civil Engineering
and Mechanics，Lanzhou University，Lanzhou，Gansu 730000，China)
Abstract：Dynamic uniaxial compressive tests on Qinghai artificial frozen silt are carried out with different dynamic stress amplitudes at the steady temperature of －0.95 ℃. The relationships between accumulated strain and vibration times for frozen silt at different dynamic stress amplitudes under two kinds of frequencies are obtained. The results show that accumulated strain increases with the increasing vibration times. The relation curves of accumulated strain and vibration times can be classified into three types，i.e. failure type，stable type and critical type. When vibration times is same，the higher the dynamic stress amplitude is，the larger the accumulated strain is. The strain rate decreases with time at the beginning and the logarithm of strain rate is linearly related to the logarithm of time. With the increase in vibration time，the strain rate of failure type curve reaches a minimum value and then increases，while the strain rate of stable type curve fluctuates in certain range. The higher the vibration frequency and dynamic stress amplitude are，the larger the strain rate is. The higher the vibration frequency is，the lower the critical dynamic stress is.
2011, Vol. 30 
