【作者】 赵淑萍； 马巍； 郑剑峰； 常小晓；

【Author】 ZHAO Shu-ping,MA Wei,ZHEN Jian-feng,CHANG Xiao-xiao (State Key Laboratory of Frozen Soil Engineering,Cold and Arid Regions Environmental and Engineering Research Institute,Chinese Academy of Sciences,Lanzhou 730000,China)

【机构】 中国科学院寒区旱区环境与工程研究所冻土工程国家重点实验室；

【摘要】 根据不同振幅动荷载的三组蠕变试验结果,比较了冻结粉土在不同动荷载作用下的蠕变变形和动蠕变强度特征,发现,当动荷载振动幅值不同时,动蠕变曲线变化规律以及动蠕变强度特征变化规律都相似,但数值上有较大差别;在相同静荷载基础上叠加不同振幅动荷载时,在整个蠕变过程中,振幅越大,变形越大。而对于卸载到零的动荷载试验来说,初始蠕变阶段和稳定蠕变阶段的变形较小,但由于蠕变速率很大,变形迅速增加,很快进入渐进流阶段,随后变形变得很大;冻土的动蠕变强度随时间有规律地衰减;动荷载的振幅越大,破坏时间越短,土体越容易发生破坏。更多还原

【Abstract】 The dynamic creep strain and creep strength are studied based on creep tests.Three groups of tests are performed (testⅠ,testⅡand testⅢ).As to testⅠand testⅡ,the static loadings of both are same and the dynamic loading of testⅡis twice as much as that of testⅠ.As to testⅢ,the minimum value of dynamic loading is near zero,and the amplitude of dynamic loading is larger more than that of testⅠand testⅡ.To all three kinds of tests,there are similar change trends of creep strain and creep strength,but with different values.The creep strain of testⅡis larger than that of testⅠ,during whole creep course.The creep strain of testⅢis less than testⅠand testⅡduring initial creep stage and steady creep stage,however,due to its higher creep strain rate during the steady creep stage and consequently a considerable strain increment,after a much shorter steady stage,it moved into the tertiary stage quickly where the strain became larger than that of testⅠand testⅡ.The dynamic creep strength of frozen silt decreases when time increases. The time to failure will be shorter and frozen soil is easier to be destroyed when the amplitude value of dynamic loading is larger.更多还原